# CoAP Component

An easy-to-use CoAP client and server implementation.

## Syntax

```text
nsoftware.IPWorksIoT.CoAP
```

## Remarks

The CoAP component provides a lightweight, fully-featured CoAP client and server implementation with DTLS support.

### Using the Component in Client Mode

While in client mode (i.e., the [Listening](#listening-property-coap-component) property is disabled; its default setting), the component can be used to send requests to a CoAP server. It can also be used to register as an observer for various server-side resources, causing the server to send notifications anytime said resources change.

By default, the component operates in NoSec mode as defined by RFC 7252. Certificate mode DTLS can be enabled by setting [SSLEnabled](#sslenabled-property-coap-component) to *True*. [UseRawPublicKey](#UseRawPublicKey) can be used to enable Raw Public Key mode.

When DTLS is enabled, relevant handshake details will be reported by the [SSLStatus](#sslstatus-event-coap-component) event. Initially, the server will present its certificate to the client. The certificate is validated by the system and the status is provided within the [SSLServerAuthentication](#sslserverauthentication-event-coap-component) event. If the *Accept* parameter of the [SSLServerAuthentication](#sslserverauthentication-event-coap-component) event is false, the *Status* parameter will tell you why. You can then set the *Accept* parameter to true to manually force acceptance of the server certificate.

In some cases, the server requires the client to present a certificate as well. In this case, a valid certificate will need to be specified via the [SSLCert](#sslcert-property-coap-component) property. This process may look like the following:

```csharp
coapclient.OnSSLServerAuthentication += (o, e) => {
  if (e.Accept) return;
  Console.Write("Server provided the following certificate:\nIssuer: " + e.CertIssuer + "\nSubject: " + e.CertSubject + "\n");
  Console.Write("The following problems have been determined for this certificate: " + e.Status + "\n");
  Console.Write("Would you like to accept anyways? [y/n] ");
  if (Console.Read() == 'y') e.Accept = true;
};

coapclient.SSLEnabled = true;
coapclient.RemoteHost = "remote_ip";
coapclient.RemotePort = 1234;
coapclient.Timeout = 30;

// if client authentication is applicable
coapclient.SSLCert = new Certificate("/path/to/cert.pfx", CertStoreTypes.cstPFXFile, "cert_password", "cert_subject");
```

 To send a request, populate the [RequestData](#requestdata-property-coap-component), [RequestContentFormat](#requestcontentformat-property-coap-component), [RequestETag](#requestetag-property-coap-component), and [RequestOptions](#requestoptions-property-coap-component) properties (if necessary, and as applicable), then call one of the following methods:

- [Get](#get-method-coap-component)
- [Post](#post-method-coap-component)
- [Put](#put-method-coap-component)
- [Delete](#delete-method-coap-component)
- [SendCustomRequest](#sendcustomrequest-method-coap-component)

The methods above require a URI as a parameter. The format of the *URI* parameter is *coap://hostname:port/resource*. The port is optional, and if not specified will default to 5683. For instance *coap://myserver/test* and *coap://myserver:5683/test* are equivalent.

Once a response is received, the [ResponseCode](#responsecode-property-coap-component), [ResponseData](#responsedata-property-coap-component), [ResponseContentFormat](#responsecontentformat-property-coap-component), [ResponseETag](#responseetag-property-coap-component), and [ResponseOptions](#responseoptions-property-coap-component) properties will be populated, and the [RequestComplete](#requestcomplete-event-coap-component) event will fire. (If the request times out, the properties are not populated, but the event still fires.)

```csharp
coap.OnRequestComplete += (s, e) => {
  Console.WriteLine("Request complete!");
  Console.WriteLine(coap.ResponseCode);
};

// Make a GET request to download a picture.
coap.Get("coap://mycoapserver/pictures/animals/cats4.dat?format=png");
// Imaginary function which accepts PNG image data and displays the picture to the user.
showPicture(coap.ResponseDataB);
```

To observe a resource, call the [StartObserving](#startobserving-method-coap-component) method. Assuming the server accepts the observer registration request, it will begin sending notifications for the resource anytime it changes. Each change notification will cause the [ResponseCode](#responsecode-property-coap-component), [ResponseData](#responsedata-property-coap-component), [ResponseContentFormat](#responsecontentformat-property-coap-component), [ResponseETag](#responseetag-property-coap-component), and [ResponseOptions](#responseoptions-property-coap-component) properties to be populated, and the [Notification](#notification-event-coap-component) event to fire.

To stop observing a resource, either call [StopObserving](#stopobserving-method-coap-component) with the same *URI* value used to call [StartObserving](#startobserving-method-coap-component), or set the [Notification](#notification-event-coap-component) event's *StopObserving* parameter to *True*.

```csharp
coap.OnNotification += (s, e) => {
  // Notifications can arrive out of order; only print to the log if this is the latest one we've received.
  if (e.IsLatest) {
    Console.WriteLine("Received notification for the resource at: " + e.URI);
    Console.WriteLine("New Value: " + coap.ResponseData);
  }
}

// Start observing a temperature sensor's data. Assume temperature values are sent back in text format.
coap.StartObserving("coap://mycoapserver/home/living_room/sensors/temperature?unit=fahrenheit");

// Assume the server accepts the request and starts sending notifications every so often.
// ...
// Later, stop observing the resource.
coap.StopObserving("coap://mycoapserver/home/living_room/sensors/temperature?unit=fahrenheit");
```

### Using the Component in Server Mode

To operate in server mode, set the [LocalPort](#localport-property-coap-component) to the port the component should listen on (typically *5683*, the standard CoAP port), then enable the [Listening](#listening-property-coap-component) property. Each time a request arrives, the [RequestData](#requestdata-property-coap-component), [RequestContentFormat](#requestcontentformat-property-coap-component), [RequestETag](#requestetag-property-coap-component), and [RequestOptions](#requestoptions-property-coap-component) properties will be populated, and the [Request](#request-event-coap-component) event will fire.

By default, the component operates in NoSec mode as defined by RFC 7252. Certificate mode DTLS can be enabled by setting [SSLEnabled](#sslenabled-property-coap-component) to *True*. [UseRawPublicKey](#UseRawPublicKey) can be used to enable Raw Public Key mode.

When DTLS is enabled, a valid certificate must be selected before the server can start listening for incoming connections. The certificate can be specified via the [SSLCert](#sslcert-property-coap-component) property. Note the certificate must contain a private key.

After doing so, calling [StartListening](#startlistening-method-coap-component) will cause the component to start listening for incoming connections. The component will listen on the interface defined by [LocalHost](#localhost-property-coap-component) and [LocalPort](#localport-property-coap-component), if specified. Otherwise, these values will be set by the component. If applicable, these values must be set before calling [StartListening](#startlistening-method-coap-component). For example:

```csharp
//coapserver.LocalHost = "some_ip_address";
//coapserver.LocalPort = 1234;
coapserver.SSLCert = new Certificate("/path/to/cert.pfx", CertStoreTypes.cstPFXFile, "cert_password", "cert_subject");

coapserver.StartListening();

Console.WriteLine("Listening on: " + coapserver.LocalHost + ":" + coapserver.LocalPort);
while (coapserver.Listening) {
  coapserver.DoEvents();
}
```

A response can be sent by populating the [ResponseCode](#responsecode-property-coap-component), [ResponseData](#responsedata-property-coap-component), [ResponseContentFormat](#responsecontentformat-property-coap-component), [ResponseETag](#responseetag-property-coap-component), and [ResponseOptions](#responseoptions-property-coap-component) properties as desired before the event finishes. Alternatively, the [Request](#request-event-coap-component) event's *SendResponse* parameter can be set to *False* in order to send a response back later. In this case, the *RequestId* value from the event should be used to call the [SendResponse](#sendresponse-method-coap-component) method later.

```csharp
coap.OnRequest += (s, e) => {
  // For the purpose of this snippet, assume we only service GET requests, which have a method code of 1.
  if (e.Method == 1) {
    Console.WriteLine("GET request received for URI path: " + e.URIPath + " and URI query params: " + e.URIQuery);
    coap.ResponseCode = "2.05"; // "Content".
    // Imaginary methods that look up the data and content format of the resource based on the URI path and URI query parameters.
    coap.ResponseData = lookupResourceData(e.URIPath, e.URIQuery);
    coap.ResponseContentFormat = lookupResourceContentFormat(e.URIPath, e.URIQuery);
  } else {
    coap.ResponseCode = "4.05"; // "Method Not Allowed".
    coap.ResponseData = "Only GET requests are allowed."; // Include a diagnostic payload.
    coap.ResponseContentFormat = "";
  }
  // Alternatively, this event could simply save the e.RequestId value somewhere, then some other code could fill in the Response*
  // properties and call the SendResponse() method later.
};

coap.OnResponseComplete += (s, e) => {
  Console.WriteLine("Response sent for request with Id " + e.RequestId);
};
```

In server mode, the component can also support resource observation. When a client attempts to register itself as an observer of a resource, the [Register](#register-event-coap-component) event will fire; setting this event's *Accept* parameter to *True* will cause the component to accept the registration.

To notify clients that a resource has changed, populate the [ResponseCode](#responsecode-property-coap-component), [ResponseData](#responsedata-property-coap-component), [ResponseContentFormat](#responsecontentformat-property-coap-component), [ResponseETag](#responseetag-property-coap-component), and [ResponseOptions](#responseoptions-property-coap-component) properties as desired, and then call the [SendNotification](#sendnotification-method-coap-component) method, passing it the URI of a resource that has registered observers.

When a client has unregistered from further change notifications, the [Unregistered](#unregistered-event-coap-component) event will fire.

```csharp
coap.OnRegister += (s, e) => {
  Console.WriteLine("Client " + e.RemoteHost + ":" + e.RemotePort + " has registered for notifications for the URI " + e.URI);
  // Imaginary method that helps ensure the application keeps track of observed URIs. The component itself maintains the
  // list of observers for each URI, so the application just needs to know that there are observers in the first place.
  observerRegisteredForURI(e.URI);
  e.Accept = true;
};
coap.OnUnregistered += (s, e) => {
  Console.WriteLine("Client " + e.RemoteHost + ":" + e.RemotePort + " has unregistered from notifications for the URI " + e.URI);
  // As above, imaginary method that helps ensure the application keeps track of observed URIs.
  observerUnregisteredForURI(e.URI);
};

// Somewhere else in the application, this sort of code might get called after a resource changes to inform any observers of
// the change. We use another imaginary method here to check if the changed resource is observed, and to get its information.
if (isResourceObserved()) {
  coap.ResponseCode = "2.05"; // "Content".
  coap.ResponseDataB = getResourceContent();
  coap.ResponseContentFormat = getResourceContentFormat();
  coap.SendNotification(getResourceURI());
}
```

## Property List

*The following is the full list of the properties of the component with short descriptions. Click on the links for further details.*

|  |  |
| --- | --- |
| [Listening](#listening-property-coap-component) | Whether the component should operate in server mode by listening for incoming requests. |
| [LocalHost](#localhost-property-coap-component) | The name of the local host or user-assigned IP interface through which connections are initiated or accepted. |
| [LocalPort](#localport-property-coap-component) | This property includes the User Datagram Protocol (UDP) port in the local host where UDP binds. |
| [PendingRequests](#pendingrequests-property-coap-component) | Collection of pending requests. |
| [RequestContentFormat](#requestcontentformat-property-coap-component) | The request content format. |
| [RequestData](#requestdata-property-coap-component) | The request data. |
| [RequestETag](#requestetag-property-coap-component) | The request ETag. |
| [RequestOptions](#requestoptions-property-coap-component) | Collection of request options. |
| [ResponseCode](#responsecode-property-coap-component) | The response code. |
| [ResponseContentFormat](#responsecontentformat-property-coap-component) | The response content format. |
| [ResponseData](#responsedata-property-coap-component) | The response data. |
| [ResponseETag](#responseetag-property-coap-component) | The response ETag. |
| [ResponseOptions](#responseoptions-property-coap-component) | Collection of response options. |
| [SSLAcceptServerCert](#sslacceptservercert-property-coap-component) | Instructs the component to unconditionally accept the server certificate that matches the supplied certificate. |
| [SSLAuthenticateClients](#sslauthenticateclients-property-coap-component) | If set to True, the server asks the client(s) for a certificate. |
| [SSLCert](#sslcert-property-coap-component) | The certificate to be used during Secure Sockets Layer (SSL) negotiation. |
| [SSLEnabled](#sslenabled-property-coap-component) | This property indicates whether Transport Layer Security/Secure Sockets Layer (TLS/SSL) is enabled. |
| [SSLServerCert](#sslservercert-property-coap-component) | The server certificate for the last established connection. |
| [Timeout](#timeout-property-coap-component) | A timeout for the component. |
| [UseConfirmableMessages](#useconfirmablemessages-property-coap-component) | Whether to use confirmable message. |

## Method List

*The following is the full list of the methods of the component with short descriptions. Click on the links for further details.*

|  |  |
| --- | --- |
| [CancelRequest](#cancelrequest-method-coap-component) | Cancels a pending request. |
| [Config](#config-method-coap-component) | Sets or retrieves a configuration setting. |
| [Delete](#delete-method-coap-component) | Sends a DELETE request to the server. |
| [DoEvents](#doevents-method-coap-component) | This method processes events from the internal message queue. |
| [Get](#get-method-coap-component) | Sends a GET request to the server. |
| [Post](#post-method-coap-component) | Sends a POST request to the server. |
| [Put](#put-method-coap-component) | Sends a PUT request to the server. |
| [Reset](#reset-method-coap-component) | This method will reset the component. |
| [SendCustomRequest](#sendcustomrequest-method-coap-component) | Sends a custom request to the server. |
| [SendNotification](#sendnotification-method-coap-component) | Sends a notification to all clients observing a given resource. |
| [SendResponse](#sendresponse-method-coap-component) | Sends a response for a given pending request to the corresponding client. |
| [StartListening](#startlistening-method-coap-component) | This method starts listening for incoming connections. |
| [StartObserving](#startobserving-method-coap-component) | Registers the component as an observer for a given resource. |
| [StopListening](#stoplistening-method-coap-component) | This method stops listening for new connections. |
| [StopObserving](#stopobserving-method-coap-component) | Unregisters the component as an observer for a given resource. |

## Event List

*The following is the full list of the events fired by the component with short descriptions. Click on the links for further details.*

|  |  |
| --- | --- |
| [Error](#error-event-coap-component) | Fired when information is available about errors during data delivery. |
| [Log](#log-event-coap-component) | Fires once for each log message. |
| [Notification](#notification-event-coap-component) | Fires when a notification is received from the server. |
| [Register](#register-event-coap-component) | Fires when a client wishes to register for notifications. |
| [Request](#request-event-coap-component) | Fires when a request is received from a client. |
| [RequestComplete](#requestcomplete-event-coap-component) | Fires when a request completes. |
| [ResponseComplete](#responsecomplete-event-coap-component) | Fires when a response has been sent to a client. |
| [SSLClientAuthentication](#sslclientauthentication-event-coap-component) | This event is fired when the client presents its credentials to the server. |
| [SSLServerAuthentication](#sslserverauthentication-event-coap-component) | Fired after the server presents its certificate to the client. |
| [SSLStatus](#sslstatus-event-coap-component) | Fired when secure connection progress messages are available. |
| [Unregistered](#unregistered-event-coap-component) | Fires when a client has unregistered from notifications. |

## Config Settings

*The following is a list of config settings for the component with short descriptions. Click on the links for further details.*

|  |  |
| --- | --- |
| [MessageId](#MessageId) | Sets the MessageId for a request. |
| [UseEmptyToken](#UseEmptyToken) | Uses an empty value for the request token. |
| [UseRawPublicKey](#UseRawPublicKey) | Whether to enable Raw Public Key mode. |
| [CACertFilePaths](#CACertFilePaths) | The paths to CA certificate files when using Mono on Unix/Linux. |
| [LogSSLPackets](#LogSSLPackets) | Controls whether SSL packets are logged when using the internal security API. |
| [ReuseSSLSession](#ReuseSSLSession) | Determines if the SSL session is reused. |
| [SSLCACerts](#SSLCACerts) | A newline separated list of CA certificates to be included when performing an SSL handshake. |
| [SSLCheckCRL](#SSLCheckCRL) | Whether to check the Certificate Revocation List for the server certificate. |
| [SSLCheckOCSP](#SSLCheckOCSP) | Whether to use OCSP to check the status of the server certificate. |
| [SSLCipherStrength](#SSLCipherStrength) | The minimum cipher strength used for bulk encryption. |
| [SSLClientCACerts](#SSLClientCACerts) | A newline separated list of CA certificates to use during SSL client certificate validation. |
| [SSLEnabledCipherSuites](#SSLEnabledCipherSuites) | The cipher suite to be used in an SSL negotiation. |
| [SSLEnabledProtocols](#SSLEnabledProtocols) | Used to enable/disable the supported security protocols. |
| [SSLEnableRenegotiation](#SSLEnableRenegotiation) | Whether the renegotiation_info SSL extension is supported. |
| [SSLIncludeCertChain](#SSLIncludeCertChain) | Whether the entire certificate chain is included in the SSLServerAuthentication event. |
| [SSLKeyLogFile](#SSLKeyLogFile) | The location of a file where per-session secrets are written for debugging purposes. |
| [SSLNegotiatedCipher](#SSLNegotiatedCipher) | Returns the negotiated cipher suite. |
| [SSLNegotiatedCipherStrength](#SSLNegotiatedCipherStrength) | Returns the negotiated cipher suite strength. |
| [SSLNegotiatedCipherSuite](#SSLNegotiatedCipherSuite) | Returns the negotiated cipher suite. |
| [SSLNegotiatedKeyExchange](#SSLNegotiatedKeyExchange) | Returns the negotiated key exchange algorithm. |
| [SSLNegotiatedKeyExchangeStrength](#SSLNegotiatedKeyExchangeStrength) | Returns the negotiated key exchange algorithm strength. |
| [SSLNegotiatedVersion](#SSLNegotiatedVersion) | Returns the negotiated protocol version. |
| [SSLSecurityFlags](#SSLSecurityFlags) | Flags that control certificate verification. |
| [SSLServerCACerts](#SSLServerCACerts) | A newline separated list of CA certificates to use during SSL server certificate validation. |
| [TLS12SignatureAlgorithms](#TLS12SignatureAlgorithms) | Defines the allowed TLS 1.2 signature algorithms when SSLProvider is set to Internal. |
| [TLS12SupportedGroups](#TLS12SupportedGroups) | The supported groups for ECC. |
| [TLS13KeyShareGroups](#TLS13KeyShareGroups) | The groups for which to pregenerate key shares. |
| [TLS13SignatureAlgorithms](#TLS13SignatureAlgorithms) | The allowed certificate signature algorithms. |
| [TLS13SupportedGroups](#TLS13SupportedGroups) | The supported groups for (EC)DHE key exchange. |
| [CaptureIPPacketInfo](#CaptureIPPacketInfo) | Used to capture the packet information. |
| [DelayHostResolution](#DelayHostResolution) | Whether the hostname is resolved when RemoteHost is set. |
| [DestinationAddress](#DestinationAddress) | Used to get the destination address from the packet information. |
| [DontFragment](#DontFragment) | Used to set the Don't Fragment flag of outgoing packets. |
| [LocalHost](#LocalHost) | The name of the local host through which connections are initiated or accepted. |
| [LocalPort](#LocalPort) | The port in the local host where the component binds. |
| [MaxPacketSize](#MaxPacketSize) | The maximum length of the packets that can be received. |
| [QOSDSCPValue](#QOSDSCPValue) | Used to specify an arbitrary QOS/DSCP setting (optional). |
| [QOSTrafficType](#QOSTrafficType) | Used to specify QOS/DSCP settings (optional). |
| [ShareLocalPort](#ShareLocalPort) | If set to True, allows more than one instance of the component to be active on the same local port. |
| [UseConnection](#UseConnection) | Determines whether to use a connected socket. |
| [UseIPv6](#UseIPv6) | Whether or not to use IPv6. |
| [AbsoluteTimeout](#AbsoluteTimeout) | Determines whether timeouts are inactivity timeouts or absolute timeouts. |
| [FirewallData](#FirewallData) | Used to send extra data to the firewall. |
| [InBufferSize](#InBufferSize) | The size in bytes of the incoming queue of the socket. |
| [OutBufferSize](#OutBufferSize) | The size in bytes of the outgoing queue of the socket. |
| [BuildInfo](#BuildInfo) | Information about the product's build. |
| [GUIAvailable](#GUIAvailable) | Whether or not a message loop is available for processing events. |
| [LicenseInfo](#LicenseInfo) | Information about the current license. |
| [MaskSensitiveData](#MaskSensitiveData) | Whether sensitive data is masked in log messages. |
| [UseFIPSCompliantAPI](#UseFIPSCompliantAPI) | Tells the component whether or not to use FIPS certified APIs. |
| [UseInternalSecurityAPI](#UseInternalSecurityAPI) | Whether or not to use the system security libraries or an internal implementation. |

# Listening Property ([CoAP](#coap-component) Component)

Whether the component should operate in server mode by listening for incoming requests.

## Syntax

```text
public bool Listening { get; }
```

## Default Value

False

## Remarks

This property indicates whether the component operates in server mode or client mode.

When this property is *false* (default), the component operate in client mode, allowing applications to send requests using the [Get](#get-method-coap-component), [Post](#post-method-coap-component), [SendCustomRequest](#sendcustomrequest-method-coap-component), etc. methods.

When this property is *true*, the component listens on [LocalPort](#localport-property-coap-component) for incoming CoAP requests, firing the [Request](#request-event-coap-component) event anytime one arrives. Applications can service these requests directly during [Request](#request-event-coap-component) events, or send separate responses later using the [SendResponse](#sendresponse-method-coap-component) method.

Applications that wish to use the component in server mode should set the [LocalPort](#localport-property-coap-component) property to the desired listening port (such as *5683*, the standard CoAP port) *before* calling [StartListening](#startlistening-method-coap-component). Otherwise the system will choose a port at random.

Use the [StartListening](#startlistening-method-coap-component) and [StopListening](#stoplistening-method-coap-component) methods to control whether the component is listening.

This property is read-only and not available at design time.

# LocalHost Property ([CoAP](#coap-component) Component)

The name of the local host or user-assigned IP interface through which connections are initiated or accepted.

## Syntax

```text
public string LocalHost { get; set; }
```

## Default Value

""

## Remarks

This property contains the name of the local host as obtained by the *gethostname()* system call, or if the user has assigned an IP address, the value of that address.

In multihomed hosts (machines with more than one IP interface) setting LocalHost to the IP address of an interface will make the component initiate connections (or accept in the case of server components) only through that interface. It is recommended to provide an IP address rather than a hostname when setting this property to ensure the desired interface is used.

If the component is connected, the LocalHost property shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multihomed hosts (machines with more than one IP interface).

NOTE: LocalHost is not persistent. You must always set it in code, and never in the property window.

# LocalPort Property ([CoAP](#coap-component) Component)

This property includes the User Datagram Protocol (UDP) port in the local host where UDP binds.

## Syntax

```text
public int LocalPort { get; set; }
```

## Default Value

0

## Remarks

The LocalPort property must be set before UDP is activated (Active is set to True). This instructs the component to bind to a specific port (or communication endpoint) in the local machine.

Setting it to *0* (default) enables the Transmission Control Protocol (TCP)/IP stack to choose a port at random. The chosen port will be shown by the LocalPort property after the connection is established.

LocalPort cannot be changed once the component is Active. Any attempt to set the LocalPort property when the component is Active will generate an error.

The LocalPort property is useful when trying to connect to services that require a trusted port on the client side.

# PendingRequests Property ([CoAP](#coap-component) Component)

Collection of pending requests.

## Syntax

```text
public CoAPRequestMap PendingRequests { get; }
```

## Remarks

This collection property holds a list of [CoAPRequest](#coaprequest-type) items.

When the component is operating in client mode (i.e., the [Listening](#listening-property-coap-component) property is disabled), each item represents an outgoing request for which a response has not yet been received.

When the component is operating in server mode (i.e., the [Listening](#listening-property-coap-component) property is enabled), each item represents an incoming request for which a response has not yet been sent.

This property is read-only and not available at design time.

 Please refer to the [CoAPRequest](#coaprequest-type) type for a complete list of fields.

# RequestContentFormat Property ([CoAP](#coap-component) Component)

The request content format.

## Syntax

```text
public int RequestContentFormat { get; set; }
```

## Default Value

-1

## Remarks

When the component is operating in client mode (i.e., the [Listening](#listening-property-coap-component) property is disabled), this property specifies the content format that should be included in outgoing requests.

When the component is operating in server mode (i.e., the [Listening](#listening-property-coap-component) property is enabled), this property is populated with the content format included in incoming requests (if any) anytime the [Request](#request-event-coap-component) event fires.

In either case, the valid set of values for this property is *-1*, or a value in the range *0* to *65535*. *-1* prevents a Content-Format option from being included when sending a request, or indicates that one was not included in a received response.

The following table provides a (non-exhaustive) list of some of the more common content formats; refer to the IANA's [CoAP Content-Formats](https://www.iana.org/assignments/core-parameters/core-parameters.xhtml#content-formats) registry for a full list.

|  |  |  |
| --- | --- | --- |
| -1 (default) | Content-Format option not included. |  |
| Value | Media Type | Encoding |
| 0 | text/plain; charset=utf-8 |  |
| 40 | application/link-format |  |
| 41 | application/xml |  |
| 42 | application/octet-stream |  |
| 47 | application/exi |  |
| 50 | application/json |  |
| 51 | application/json-patch+json |  |
| 52 | application/merge-patch+json |  |
| 60 | application/cbor |  |
| 61 | application/cwt |  |
| 62 | application/multipart-core |  |
| 63 | application/cbor-seq |  |
| 11050 | application/json | deflate |
| 11060 | application/cbor | deflate |

This property is not available at design time.

# RequestData Property ([CoAP](#coap-component) Component)

The request data.

## Syntax

```text
public string RequestData { get; set; }
public byte[] RequestDataB { get; set; }
```

## Default Value

""

## Remarks

When the component is operating in client mode (i.e., the [Listening](#listening-property-coap-component) property is disabled), this property specifies the data that should be included in requests sent using [Post](#post-method-coap-component), [Put](#put-method-coap-component), or [SendCustomRequest](#sendcustomrequest-method-coap-component).

When the component is operating in server mode (i.e., the [Listening](#listening-property-coap-component) property is enabled), this property is populated with the data included in incoming requests (if any) anytime the [Request](#request-event-coap-component) event fires.

This property is not available at design time.

# RequestETag Property ([CoAP](#coap-component) Component)

The request ETag.

## Syntax

```text
public string RequestETag { get; set; }
public byte[] RequestETagB { get; set; }
```

## Default Value

""

## Remarks

When the component is operating in client mode (i.e., the [Listening](#listening-property-coap-component) property is disabled), this property specifies the ETag that should be included in outgoing requests. Leave it empty to prevent an Etag option from being included.

When the component is operating in server mode (i.e., the [Listening](#listening-property-coap-component) property is enabled), this property is populated with the ETag included in incoming requests (if any) anytime the [Request](#request-event-coap-component) event fires. It will be empty if an Etag option was not included.

This property is not available at design time.

# RequestOptions Property ([CoAP](#coap-component) Component)

Collection of request options.

## Syntax

```text
public CoAPOptionList RequestOptions { get; }
```

## Remarks

This collection property holds a list of [CoAPOption](#coapoption-type) items.

When the component is operating in client mode (i.e., the [Listening](#listening-property-coap-component) property is disabled), each item represents an option that will be included in the next outgoing request.

When the component is operating in server mode (i.e., the [Listening](#listening-property-coap-component) property is enabled), each item represents an option included in the most-recently-received request.

This property is not available at design time.

 Please refer to the [CoAPOption](#coapoption-type) type for a complete list of fields.

# ResponseCode Property ([CoAP](#coap-component) Component)

The response code.

## Syntax

```text
public string ResponseCode { get; set; }
```

## Default Value

""

## Remarks

When the component is operating in client mode (i.e., the [Listening](#listening-property-coap-component) property is disabled), this property is populated with the response code included in incoming responses anytime the [RequestComplete](#requestcomplete-event-coap-component) event fires.

When the component is operating in server mode (i.e., the [Listening](#listening-property-coap-component) property is enabled), this property specifies the response code that should be included in outgoing responses (regardless of whether they are sent immediately after [Request](#request-event-coap-component) fires, or later using [SendResponse](#sendresponse-method-coap-component) or [SendNotification](#sendnotification-method-coap-component)).

In either case, the valid set of values for this property are strings of the format *c.dd*, where *c* is a class value in the range *2* to *7*, and *dd* is a detail value in the range *00* to *31*.

The following table provides a (non-exhaustive) list of some of the more common response codes; refer to the IANA's [CoAP Response Codes](https://www.iana.org/assignments/core-parameters/core-parameters.xhtml#response-codes) registry for a full list.

| Code | Description |
| --- | --- |
| 2.01 | Created |
| 2.02 | Deleted |
| 2.03 | Valid |
| 2.04 | Changed |
| 2.05 | Content |
| 2.31 | Continue |
| 4.00 | Bad Request |
| 4.01 | Unauthorized |
| 4.02 | Bad Option |
| 4.03 | Forbidden |
| 4.04 | Not Found |
| 4.12 | Precondition Failed |
| 5.00 | Internal Server Error |
| 5.01 | Not Implemented |
| 5.02 | Bad Gateway |
| 5.03 | Service Unavailable |
| 5.04 | Gateway Timeout |

This property is not available at design time.

# ResponseContentFormat Property ([CoAP](#coap-component) Component)

The response content format.

## Syntax

```text
public int ResponseContentFormat { get; set; }
```

## Default Value

-1

## Remarks

When the component is operating in client mode (i.e., the [Listening](#listening-property-coap-component) property is disabled), this property is populated with the content format included in incoming responses anytime the [RequestComplete](#requestcomplete-event-coap-component) event fires.

When the component is operating in server mode (i.e., the [Listening](#listening-property-coap-component) property is enabled), this property specifies the content format that should be included in outgoing responses (regardless of whether they are sent immediately after [Request](#request-event-coap-component) fires, or later using [SendResponse](#sendresponse-method-coap-component) or [SendNotification](#sendnotification-method-coap-component)).

In either case, the valid set of values for this property is *-1*, or a value in the range *0* to *65535*. *-1* prevents a Content-Format option from being included when sending a response, or indicates that one was not included in a received response.

The following table provides a (non-exhaustive) list of some of the more common content formats; refer to the IANA's [CoAP Content-Formats](https://www.iana.org/assignments/core-parameters/core-parameters.xhtml#content-formats) registry for a full list.

|  |  |  |
| --- | --- | --- |
| -1 (default) | Content-Format option not included. |  |
| Value | Media Type | Encoding |
| 0 | text/plain; charset=utf-8 |  |
| 40 | application/link-format |  |
| 41 | application/xml |  |
| 42 | application/octet-stream |  |
| 47 | application/exi |  |
| 50 | application/json |  |
| 51 | application/json-patch+json |  |
| 52 | application/merge-patch+json |  |
| 60 | application/cbor |  |
| 61 | application/cwt |  |
| 62 | application/multipart-core |  |
| 63 | application/cbor-seq |  |
| 11050 | application/json | deflate |
| 11060 | application/cbor | deflate |

This property is not available at design time.

# ResponseData Property ([CoAP](#coap-component) Component)

The response data.

## Syntax

```text
public string ResponseData { get; set; }
public byte[] ResponseDataB { get; set; }
```

## Default Value

""

## Remarks

When the component is operating in client mode (i.e., the [Listening](#listening-property-coap-component) property is disabled), this property is populated with the data included in incoming responses (if any) anytime the [RequestComplete](#requestcomplete-event-coap-component) event fires.

When the component is operating in server mode (i.e., the [Listening](#listening-property-coap-component) property is enabled), this property specifies the data that should be included in outgoing responses (regardless of whether they are sent immediately after [Request](#request-event-coap-component) fires, or later using [SendResponse](#sendresponse-method-coap-component) or [SendNotification](#sendnotification-method-coap-component)).

This property is not available at design time.

# ResponseETag Property ([CoAP](#coap-component) Component)

The response ETag.

## Syntax

```text
public string ResponseETag { get; set; }
public byte[] ResponseETagB { get; set; }
```

## Default Value

""

## Remarks

When the component is operating in client mode (i.e., the [Listening](#listening-property-coap-component) property is disabled), this property is populated with the ETag included in incoming responses (if any) anytime the [RequestComplete](#requestcomplete-event-coap-component) event fires. It will be empty if an Etag option was not included.

When the component is operating in server mode (i.e., the [Listening](#listening-property-coap-component) property is enabled), this property specifies the ETag that should be included in outgoing responses (regardless of whether they are sent immediately after [Request](#request-event-coap-component) fires, or later using [SendResponse](#sendresponse-method-coap-component) or [SendNotification](#sendnotification-method-coap-component)). Leave it empty to prevent an Etag option from being included.

This property is not available at design time.

# ResponseOptions Property ([CoAP](#coap-component) Component)

Collection of response options.

## Syntax

```text
public CoAPOptionList ResponseOptions { get; }
```

## Remarks

This collection property holds a list of [CoAPOption](#coapoption-type) items.

When the component is operating in client mode (i.e., the [Listening](#listening-property-coap-component) property is disabled), each item represents an option included in the most-recently-received response.

When the component is operating in server mode (i.e., the [Listening](#listening-property-coap-component) property is enabled), each item represents an option that will be included in the next outgoing response.

This property is not available at design time.

 Please refer to the [CoAPOption](#coapoption-type) type for a complete list of fields.

# SSLAcceptServerCert Property ([CoAP](#coap-component) Component)

Instructs the component to unconditionally accept the server certificate that matches the supplied certificate.

## Syntax

```text
public Certificate SSLAcceptServerCert { get; set; }
```

## Remarks

If it finds any issues with the certificate presented by the server, the component will normally terminate the connection with an error.

You may override this behavior by supplying a value for SSLAcceptServerCert. If the certificate supplied in SSLAcceptServerCert is the same as the certificate presented by the server, then the server certificate is accepted unconditionally, and the connection will continue normally.

NOTE: This functionality is provided only for cases in which you otherwise know that you are communicating with the right server. If used improperly, this property may create a security breach. Use it at your own risk.

 Please refer to the [Certificate](#certificate-type) type for a complete list of fields.

# SSLAuthenticateClients Property ([CoAP](#coap-component) Component)

If set to True, the server asks the client(s) for a certificate.

## Syntax

```text
public bool SSLAuthenticateClients { get; set; }
```

## Default Value

False

## Remarks

This property is used in conjunction with the [SSLClientAuthentication](#sslclientauthentication-event-coap-component) event. Please refer to the documentation of the [SSLClientAuthentication](#sslclientauthentication-event-coap-component) event for details.

# SSLCert Property ([CoAP](#coap-component) Component)

The certificate to be used during Secure Sockets Layer (SSL) negotiation.

## Syntax

```text
public Certificate SSLCert { get; set; }
```

## Remarks

This property includes the digital certificate that the component will use during SSL negotiation. Set this property to a valid certificate before starting SSL negotiation. To set a certificate, you may set the [Encoded](#Certificate_f_Encoded) field to the encoded certificate. To select a certificate, use the store and subject fields.

 Please refer to the [Certificate](#certificate-type) type for a complete list of fields.

# SSLEnabled Property ([CoAP](#coap-component) Component)

This property indicates whether Transport Layer Security/Secure Sockets Layer (TLS/SSL) is enabled.

## Syntax

```text
public bool SSLEnabled { get; set; }
```

## Default Value

False

## Remarks

This property specifies whether TLS/SSL is enabled in the component. When False (default), the component operates in plaintext mode. When True, TLS/SSL is enabled.

TLS/SSL may also be enabled by setting SSLStartMode. Setting SSLStartMode will automatically update this property value.

This property is not available at design time.

# SSLServerCert Property ([CoAP](#coap-component) Component)

The server certificate for the last established connection.

## Syntax

```text
public Certificate SSLServerCert { get; }
```

## Remarks

This property contains the server certificate for the last established connection.

SSLServerCert is reset every time a new connection is attempted. &

This property is read-only.

 Please refer to the [Certificate](#certificate-type) type for a complete list of fields.

# Timeout Property ([CoAP](#coap-component) Component)

A timeout for the component.

## Syntax

```text
public int Timeout { get; set; }
```

## Default Value

60

## Remarks

This property specifies the number of seconds that the component should wait, synchronously, for a response to be received. A value of *0* means that the component will send the request data (when operating in client mode) or the response data (when operating in server mode) asynchronously, and then wait indefinitely, firing the applicable event once complete.

The component will use [DoEvents](#doevents-method-coap-component) to enter an efficient wait loop during any potential waiting period, ensuring that all system events are processed immediately as they arrive. This ensures that the host application does not "freeze" and remains responsive.

If Timeout expires, and the response has not yet been received, the component throws an exception.

# UseConfirmableMessages Property ([CoAP](#coap-component) Component)

Whether to use confirmable message.

## Syntax

```text
public bool UseConfirmableMessages { get; set; }
```

## Default Value

True

## Remarks

This property specifies whether the component should send requests (if operating in client mode; i.e., when the [Listening](#listening-property-coap-component) property is disabled) or responses (if operating in server mode; i.e., when the [Listening](#listening-property-coap-component) property is enabled) using confirmable messages instead of unconfirmable messages.

Using confirmable messages increases reliability, since the component will automatically retransmit a message until it receives a confirmation from the remote host that the message was received. Note that the retransmission period is not infinite; eventually the component will assume that the message is undeliverable and time out the retransmission process.

Using non-confirmable messages reduces the amount of network traffic, but at the cost of reliability, since the component has no way to know whether a given message was received by the remote host, or lost in transit.

# CancelRequest Method ([CoAP](#coap-component) Component)

Cancels a pending request.

## Syntax

```text
public void CancelRequest(string requestId);

Async Version
public async Task CancelRequest(string requestId);
public async Task CancelRequest(string requestId, CancellationToken cancellationToken);
```

## Remarks

This method cancels the request in the [PendingRequests](#pendingrequests-property-coap-component) collection identified by *RequestId*.

When the component is operating in client mode, the requests in the [PendingRequests](#pendingrequests-property-coap-component) collection represent outgoing requests for which responses have not yet been received. Canceling one will cause the [RequestComplete](#requestcomplete-event-coap-component) event to fire with an appropriate *ErrorCode* and *ErrorDescription*.

When the component is operating in server mode, the requests in the [PendingRequests](#pendingrequests-property-coap-component) collection represent incoming requests for which responses have not yet been sent. Canceling one will cause the [ResponseComplete](#responsecomplete-event-coap-component) event to fire with an appropriate *ErrorCode* and *ErrorDescription*.

# Config Method ([CoAP](#coap-component) Component)

Sets or retrieves a configuration setting.

## Syntax

```text
public string Config(string configurationString);

Async Version
public async Task<string> Config(string configurationString);
public async Task<string> Config(string configurationString, CancellationToken cancellationToken);
```

## Remarks

Config is a generic method available in every component. It is used to set and retrieve [configuration settings](#config-settings-coap-component) for the component.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these *internal properties* is provided through the Config method.

To set a configuration setting named *PROPERTY*, you must call *Config("PROPERTY=VALUE")*, where *VALUE* is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a [configuration setting](#config-settings-coap-component), you must call *Config("PROPERTY")*. The value will be returned as a string.

# Delete Method ([CoAP](#coap-component) Component)

Sends a DELETE request to the server.

## Syntax

```text
public string Delete(string URI);

Async Version
public async Task<string> Delete(string URI);
public async Task<string> Delete(string URI, CancellationToken cancellationToken);
```

## Remarks

This method sends the server a DELETE request for the resource identified by *URI*. If the [RequestETag](#requestetag-property-coap-component) property is non-empty, its value will be used to include an Etag option in the request. Any additional options present in the [RequestOptions](#requestoptions-property-coap-component) collection will be included as well.

The format of the *URI* parameter is *coap://hostname:port/resource*. The port is optional, and if not specified will default to 5683. For instance *coap://myserver/test* and *coap://myserver:5683/test* are equivalent.

If the [UseConfirmableMessages](#useconfirmablemessages-property-coap-component) property is enabled when this method is called, the component will automatically retransmit the request message (if necessary) until it receives confirmation from the server that it was received. Note that the retransmission period is not infinite; eventually the component will assume that the message is undeliverable and time out the request.

If the [Timeout](#timeout-property-coap-component) property is greater than *0*, this method will block until either a response is received, the specified timeout interval elapses, or (if [UseConfirmableMessages](#useconfirmablemessages-property-coap-component) is enabled) the retransmission period elapses; whichever occurs first. It will then return empty string.

If the [Timeout](#timeout-property-coap-component) property is *0*, a record of the request will be added to the [PendingRequests](#pendingrequests-property-coap-component) collection, and this method will finish immediately, returning an Id for the request. Passing this Id to the [CancelRequest](#cancelrequest-method-coap-component) method will cancel the request (assuming it is still pending at that time).

Once a response is received, or the request times out, the component will do the following:

- Populate the **Response*** properties (unless the request timed out).
- Remove the request record from the [PendingRequests](#pendingrequests-property-coap-component) collection, if necessary.
- Fire the [RequestComplete](#requestcomplete-event-coap-component) event.

Note: This method can only be called when the component is operating in client mode (i.e., when the [Listening](#listening-property-coap-component) property is disabled).

# DoEvents Method ([CoAP](#coap-component) Component)

This method processes events from the internal message queue.

## Syntax

```text
public void DoEvents();

Async Version
public async Task DoEvents();
public async Task DoEvents(CancellationToken cancellationToken);
```

## Remarks

When DoEvents is called, the component processes any available events. If no events are available, it waits for a preset period of time, and then returns.

# Get Method ([CoAP](#coap-component) Component)

Sends a GET request to the server.

## Syntax

```text
public string Get(string URI);

Async Version
public async Task<string> Get(string URI);
public async Task<string> Get(string URI, CancellationToken cancellationToken);
```

## Remarks

This method sends the server a GET request for the resource identified by *URI*. If the [RequestETag](#requestetag-property-coap-component) property is non-empty, its value will be used to include an Etag option in the request. Any additional options present in the [RequestOptions](#requestoptions-property-coap-component) collection will be included as well.

The format of the *URI* parameter is *coap://hostname:port/resource*. The port is optional, and if not specified will default to 5683. For instance *coap://myserver/test* and *coap://myserver:5683/test* are equivalent.

If the [UseConfirmableMessages](#useconfirmablemessages-property-coap-component) property is enabled when this method is called, the component will automatically retransmit the request message (if necessary) until it receives confirmation from the server that it was received. Note that the retransmission period is not infinite; eventually the component will assume that the message is undeliverable and time out the request.

If the [Timeout](#timeout-property-coap-component) property is greater than *0*, this method will block until either a response is received, the specified timeout interval elapses, or (if [UseConfirmableMessages](#useconfirmablemessages-property-coap-component) is enabled) the retransmission period elapses; whichever occurs first. It will then return empty string.

If the [Timeout](#timeout-property-coap-component) property is *0*, a record of the request will be added to the [PendingRequests](#pendingrequests-property-coap-component) collection, and this method will finish immediately, returning an Id for the request. Passing this Id to the [CancelRequest](#cancelrequest-method-coap-component) method will cancel the request (assuming it is still pending at that time).

Once a response is received, or the request times out, the component will do the following:

- Populate the **Response*** properties (unless the request timed out).
- Remove the request record from the [PendingRequests](#pendingrequests-property-coap-component) collection, if necessary.
- Fire the [RequestComplete](#requestcomplete-event-coap-component) event.

Note: This method can only be called when the component is operating in client mode (i.e., when the [Listening](#listening-property-coap-component) property is disabled).

# Post Method ([CoAP](#coap-component) Component)

Sends a POST request to the server.

## Syntax

```text
public string Post(string URI);

Async Version
public async Task<string> Post(string URI);
public async Task<string> Post(string URI, CancellationToken cancellationToken);
```

## Remarks

This method sends the server a POST request for the resource identified by *URI*. The [RequestData](#requestdata-property-coap-component) property specifies the data that will be sent in the request. If the [RequestContentFormat](#requestcontentformat-property-coap-component) and/or [RequestETag](#requestetag-property-coap-component) properties are non-empty, their values will be used to include Content-Format and Etag options in the request (respectively). Any additional options present in the [RequestOptions](#requestoptions-property-coap-component) collection will be included as well.

The format of the *URI* parameter is *coap://hostname:port/resource*. The port is optional, and if not specified will default to 5683. For instance *coap://myserver/test* and *coap://myserver:5683/test* are equivalent.

If the [UseConfirmableMessages](#useconfirmablemessages-property-coap-component) property is enabled when this method is called, the component will automatically retransmit the request message (if necessary) until it receives confirmation from the server that it was received. Note that the retransmission period is not infinite; eventually the component will assume that the message is undeliverable and time out the request.

If the [Timeout](#timeout-property-coap-component) property is greater than *0*, this method will block until either a response is received, the specified timeout interval elapses, or (if [UseConfirmableMessages](#useconfirmablemessages-property-coap-component) is enabled) the retransmission period elapses; whichever occurs first. It will then return empty string.

If the [Timeout](#timeout-property-coap-component) property is *0*, a record of the request will be added to the [PendingRequests](#pendingrequests-property-coap-component) collection, and this method will finish immediately, returning an Id for the request. Passing this Id to the [CancelRequest](#cancelrequest-method-coap-component) method will cancel the request (assuming it is still pending at that time).

Once a response is received, or the request times out, the component will do the following:

- Populate the **Response*** properties (unless the request timed out).
- Remove the request record from the [PendingRequests](#pendingrequests-property-coap-component) collection, if necessary.
- Fire the [RequestComplete](#requestcomplete-event-coap-component) event.

Note: This method can only be called when the component is operating in client mode (i.e., when the [Listening](#listening-property-coap-component) property is disabled).

# Put Method ([CoAP](#coap-component) Component)

Sends a PUT request to the server.

## Syntax

```text
public string Put(string URI);

Async Version
public async Task<string> Put(string URI);
public async Task<string> Put(string URI, CancellationToken cancellationToken);
```

## Remarks

This method sends the server a PUT request for the resource identified by *URI*. The [RequestData](#requestdata-property-coap-component) property specifies the data that will be sent in the request. If the [RequestContentFormat](#requestcontentformat-property-coap-component) and/or [RequestETag](#requestetag-property-coap-component) properties are non-empty, their values will be used to include Content-Format and Etag options in the request (respectively). Any additional options present in the [RequestOptions](#requestoptions-property-coap-component) collection will be included as well.

The format of the *URI* parameter is *coap://hostname:port/resource*. The port is optional, and if not specified will default to 5683. For instance *coap://myserver/test* and *coap://myserver:5683/test* are equivalent.

If the [UseConfirmableMessages](#useconfirmablemessages-property-coap-component) property is enabled when this method is called, the component will automatically retransmit the request message (if necessary) until it receives confirmation from the server that it was received. Note that the retransmission period is not infinite; eventually the component will assume that the message is undeliverable and time out the request.

If the [Timeout](#timeout-property-coap-component) property is greater than *0*, this method will block until either a response is received, the specified timeout interval elapses, or (if [UseConfirmableMessages](#useconfirmablemessages-property-coap-component) is enabled) the retransmission period elapses; whichever occurs first. It will then return empty string.

If the [Timeout](#timeout-property-coap-component) property is *0*, a record of the request will be added to the [PendingRequests](#pendingrequests-property-coap-component) collection, and this method will finish immediately, returning an Id for the request. Passing this Id to the [CancelRequest](#cancelrequest-method-coap-component) method will cancel the request (assuming it is still pending at that time).

Once a response is received, or the request times out, the component will do the following:

- Populate the **Response*** properties (unless the request timed out).
- Remove the request record from the [PendingRequests](#pendingrequests-property-coap-component) collection, if necessary.
- Fire the [RequestComplete](#requestcomplete-event-coap-component) event.

Note: This method can only be called when the component is operating in client mode (i.e., when the [Listening](#listening-property-coap-component) property is disabled).

# Reset Method ([CoAP](#coap-component) Component)

This method will reset the component.

## Syntax

```text
public void Reset();

Async Version
public async Task Reset();
public async Task Reset(CancellationToken cancellationToken);
```

## Remarks

This method will reset the component's properties to their default values.

# SendCustomRequest Method ([CoAP](#coap-component) Component)

Sends a custom request to the server.

## Syntax

```text
public string SendCustomRequest(string URI, int method);

Async Version
public async Task<string> SendCustomRequest(string URI, int method);
public async Task<string> SendCustomRequest(string URI, int method, CancellationToken cancellationToken);
```

## Remarks

This method sends the server a custom request for the resource identified by *URI*. The *Method* parameter specifies the request's method code. The following table provides a (non-exhaustive) list of some of the more common method codes; refer to the IANA's [CoAP Method Codes](https://www.iana.org/assignments/core-parameters/core-parameters.xhtml#method-codes) registry for a full list.

| Method Code | Name |
| --- | --- |
| 1 | GET |
| 2 | POST |
| 3 | PUT |
| 4 | DELETE |
| 5 | FETCH |
| 6 | PATCH |

The [RequestData](#requestdata-property-coap-component) property specifies the data that will be sent in the request. If the [RequestContentFormat](#requestcontentformat-property-coap-component) and/or [RequestETag](#requestetag-property-coap-component) properties are non-empty, their values will be used to include Content-Format and Etag options in the request (respectively). Any additional options present in the [RequestOptions](#requestoptions-property-coap-component) collection will be included as well.

The format of the *URI* parameter is *coap://hostname:port/resource*. The port is optional, and if not specified will default to 5683. For instance *coap://myserver/test* and *coap://myserver:5683/test* are equivalent.

If the [UseConfirmableMessages](#useconfirmablemessages-property-coap-component) property is enabled when this method is called, the component will automatically retransmit the request message (if necessary) until it receives confirmation from the server that it was received. Note that the retransmission period is not infinite; eventually the component will assume that the message is undeliverable and time out the request.

If the [Timeout](#timeout-property-coap-component) property is greater than *0*, this method will block until either a response is received, the specified timeout interval elapses, or (if [UseConfirmableMessages](#useconfirmablemessages-property-coap-component) is enabled) the retransmission period elapses; whichever occurs first. It will then return empty string.

If the [Timeout](#timeout-property-coap-component) property is *0*, a record of the request will be added to the [PendingRequests](#pendingrequests-property-coap-component) collection, and this method will finish immediately, returning an Id for the request. Passing this Id to the [CancelRequest](#cancelrequest-method-coap-component) method will cancel the request (assuming it is still pending at that time).

Once a response is received, or the request times out, the component will do the following:

- Populate the **Response*** properties (unless the request timed out).
- Remove the request record from the [PendingRequests](#pendingrequests-property-coap-component) collection, if necessary.
- Fire the [RequestComplete](#requestcomplete-event-coap-component) event.

Note: This method can only be called when the component is operating in client mode (i.e., when the [Listening](#listening-property-coap-component) property is disabled).

# SendNotification Method ([CoAP](#coap-component) Component)

Sends a notification to all clients observing a given resource.

## Syntax

```text
public void SendNotification(string URI);

Async Version
public async Task SendNotification(string URI);
public async Task SendNotification(string URI, CancellationToken cancellationToken);
```

## Remarks

This method sends a notification to all clients observing the resource identified by *URI*, notifying them of its latest state. Clients should be notified whenever a resource's content changes (or periodically, if it changes very often) by sending a 2.xx response code; typically *2.03* "Valid" or *2.05* "Content". Clients should *also* be notified if a resource can no longer be observed (e.g., when it is deleted) by sending a notification with a non-2.xx response code (e.g., *4.04* "Not Found"). The component will automatically unregister all observers when a non-2.xx notification is sent.

The [ResponseData](#responsedata-property-coap-component) property specifies the data that will be sent in the response, and the [ResponseCode](#responsecode-property-coap-component) property specifies the response code. If the [ResponseContentFormat](#responsecontentformat-property-coap-component) and/or [ResponseETag](#responseetag-property-coap-component) properties are non-empty, their values will be used to include Content-Format and Etag options in the response (respectively). Any additional options present in the [ResponseOptions](#responseoptions-property-coap-component) collection will be included as well.

If the [UseConfirmableMessages](#useconfirmablemessages-property-coap-component) property is enabled when this method is called, the component will automatically retransmit the response message (if necessary) until it receives confirmation from the client that it was received. Note that the retransmission period is not infinite; eventually the component will assume that the message is undeliverable and time out the response.

Note: This method can only be called when the component is operating in server mode (i.e., when the [Listening](#listening-property-coap-component) property is enabled).

# SendResponse Method ([CoAP](#coap-component) Component)

Sends a response for a given pending request to the corresponding client.

## Syntax

```text
public void SendResponse(string requestId);

Async Version
public async Task SendResponse(string requestId);
public async Task SendResponse(string requestId, CancellationToken cancellationToken);
```

## Remarks

This method sends a response for the request in the [PendingRequests](#pendingrequests-property-coap-component) collection identified by *RequestId*. The [ResponseData](#responsedata-property-coap-component) property specifies the data that will be sent in the response, and the [ResponseCode](#responsecode-property-coap-component) property specifies the response code. If the [ResponseContentFormat](#responsecontentformat-property-coap-component) and/or [ResponseETag](#responseetag-property-coap-component) properties are non-empty, their values will be used to include Content-Format and Etag options in the response (respectively). Any additional options present in the [ResponseOptions](#responseoptions-property-coap-component) collection will be included as well.

If the [UseConfirmableMessages](#useconfirmablemessages-property-coap-component) property is enabled when this method is called, the component will automatically retransmit the response message (if necessary) until it receives confirmation from the client that it was received. Note that the retransmission period is not infinite; eventually the component will assume that the message is undeliverable and time out the response. The [ResponseComplete](#responsecomplete-event-coap-component) event will fire once the message receipt is confirmed (or once the retransmission period elapses).

If the [UseConfirmableMessages](#useconfirmablemessages-property-coap-component) property is disabled, the [ResponseComplete](#responsecomplete-event-coap-component) event will fire immediately instead, since there is no way to know whether the client received the response.

Note: This method can only be called when the component is operating in server mode (i.e., when the [Listening](#listening-property-coap-component) property is enabled).

# StartListening Method ([CoAP](#coap-component) Component)

This method starts listening for incoming connections.

## Syntax

```text
public void StartListening();

Async Version
public async Task StartListening();
public async Task StartListening(CancellationToken cancellationToken);
```

## Remarks

This method begins listening for incoming connections on the port specified by [LocalPort](#localport-property-coap-component). Once listening, events will fire as new clients connect and data are transferred.

To stop listening for new connections, call [StopListening](#stoplistening-method-coap-component). To stop listening for new connections and to disconnect all existing clients, call Shutdown.

This method begins listening for incoming connections on the port specified by [LocalPort](#localport-property-coap-component). Once listening, events will fire as new clients connect and data are transferred.

To stop listening for new connections, call [StopListening](#stoplistening-method-coap-component). To stop listening for new connections and to disconnect all existing clients, call Shutdown.

# StartObserving Method ([CoAP](#coap-component) Component)

Registers the component as an observer for a given resource.

## Syntax

```text
public string StartObserving(string URI);

Async Version
public async Task<string> StartObserving(string URI);
public async Task<string> StartObserving(string URI, CancellationToken cancellationToken);
```

## Remarks

This method registers the component as an observer for the resource identified by *URI*. If the server accepts the registration, then it will periodically notify the component about any changes to the specified resource. These "change notifications" are exposed via the [Notification](#notification-event-coap-component) event.

This method operates in the exact same manner as the [Get](#get-method-coap-component) method, with the exception of the two things listed below. Refer to the [Get](#get-method-coap-component) method's documentation for more information.

1. When constructing the request, the component automatically includes an Observe option. The presence of this option is what indicates to the server that the component wishes to register itself as an observer for the specified resource.
2. When the server receives the request, its response causes the [Notification](#notification-event-coap-component) event to fire instead of the [RequestComplete](#requestcomplete-event-coap-component) event. (Unless it decides to reject the registration, in which case it will handle the request just like a normal GET request, and the [RequestComplete](#requestcomplete-event-coap-component) event will fire when its response is received, just like it would if [Get](#get-method-coap-component) had been called.)

Once the component has successfully registered itself as an observer, the server will continue to deliver change notifications for the specified resource until the component unregisters, or the resource can no longer be observed (e.g., if it is deleted). To unregister, either call the [StopObserving](#stopobserving-method-coap-component) method with the same *URI* value, or set the [Notification](#notification-event-coap-component) event's *StopObserving* parameter to *True*.

Note: This method can only be called when the component is operating in client mode (i.e., when the [Listening](#listening-property-coap-component) property is disabled).

# StopListening Method ([CoAP](#coap-component) Component)

This method stops listening for new connections.

## Syntax

```text
public void StopListening();

Async Version
public async Task StopListening();
public async Task StopListening(CancellationToken cancellationToken);
```

## Remarks

This method stops listening for new connections. After being called, any new connection attempts will be rejected. Calling this method does not disconnect existing connections.

To stop listening and to disconnect all existing clients, call Shutdown instead.

This method stops listening for new connections. After being called, any new connection attempts will be rejected. Calling this method does not disconnect existing connections.

To stop listening and to disconnect all existing clients, call Shutdown instead.

# StopObserving Method ([CoAP](#coap-component) Component)

Unregisters the component as an observer for a given resource.

## Syntax

```text
public void StopObserving(string URI);

Async Version
public async Task StopObserving(string URI);
public async Task StopObserving(string URI, CancellationToken cancellationToken);
```

## Remarks

This method unregisters the component as an observer for the resource identified by *URI*. This method operates in the exact same manner as the [Get](#get-method-coap-component) method, with the exception of the two things below; refer to the [Get](#get-method-coap-component) method's documentation for more information:

1. When constructing the request, the component automatically includes an Observe option with a value of *1*. The presence of this option indicates to the server that the component wishes to unregister from further change notifications.
2. This method, unlike [Get](#get-method-coap-component), does not return a request Id.

Note: This method can only be called when the component is operating in client mode (i.e., when the [Listening](#listening-property-coap-component) property is disabled).

# Error Event ([CoAP](#coap-component) Component)

Fired when information is available about errors during data delivery.

## Syntax

```text
public event OnErrorHandler OnError;

public delegate void OnErrorHandler(object sender, CoAPErrorEventArgs e);

public class CoAPErrorEventArgs : EventArgs {
  public int ErrorCode { get; }
  public string Description { get; }
}
```

## Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the component throws an exception.

The *ErrorCode* parameter contains an error code, and the *Description* parameter contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the [Error Codes](#trappable-errors-coap-component) section.

# Log Event ([CoAP](#coap-component) Component)

Fires once for each log message.

## Syntax

```text
public event OnLogHandler OnLog;

public delegate void OnLogHandler(object sender, CoAPLogEventArgs e);

public class CoAPLogEventArgs : EventArgs {
  public int LogLevel { get; }
  public string Message { get; }
}
```

## Remarks

This event fires once for each log message generated by the component. The verbosity is controlled by the [LogLevel](#LogLevel) setting.

*LogLevel* indicates the level of the *Message*. Possible values are:

|  |  |
| --- | --- |
| 0 (None) | No events are logged. |
| 1 (Info - default) | Informational events are logged. |
| 2 (Verbose) | Detailed data is logged. |
| 3 (Debug) | Debug data is logged. |

# Notification Event ([CoAP](#coap-component) Component)

Fires when a notification is received from the server.

## Syntax

```text
public event OnNotificationHandler OnNotification;

public delegate void OnNotificationHandler(object sender, CoAPNotificationEventArgs e);

public class CoAPNotificationEventArgs : EventArgs {
  public string URI { get; }
  public bool IsLatest { get; }
  public bool StopObserving { get; set; }
}
```

## Remarks

This event fires when the component receives a notification from that server that some observed resource has changed. Query the [ResponseCode](#responsecode-property-coap-component), [ResponseData](#responsedata-property-coap-component), [ResponseContentFormat](#responsecontentformat-property-coap-component), [ResponseETag](#responseetag-property-coap-component), and [ResponseOptions](#responseoptions-property-coap-component) properties to obtain the new resource information.

Note that, in some cases, the server may no longer be able to deliver notifications for a resource (e.g., if it is deleted). In such cases, the [ResponseCode](#responsecode-property-coap-component) property will be populated with a non-2.xx code (e.g., *4.04* "Not Found") to indicate why the resource can no longer be observed. No further notifications will be delivered for the resource after such a notification arrives.

The *URI* parameter identifies the resource that has changed.

The *IsLatest* parameter reflects whether this notification actually has the most recent resource information available, since it is possible for notifications to arrive out of order under certain circumstances.

The *StopObserving* parameter specifies whether the component should stop observing the resource identified by *URI*. This parameter is *False* by default, set it to *True* to have the component unregister itself from further notifications. (Note: in the event of a non-2.xx notification, this parameter will be *True* by default instead, and changing it to *False* will have no effect.)

Note: This event is only used when the component is operating in client mode (i.e., when the [Listening](#listening-property-coap-component) property is disabled).

# Register Event ([CoAP](#coap-component) Component)

Fires when a client wishes to register for notifications.

## Syntax

```text
public event OnRegisterHandler OnRegister;

public delegate void OnRegisterHandler(object sender, CoAPRegisterEventArgs e);

public class CoAPRegisterEventArgs : EventArgs {
  public string RemoteHost { get; }
  public int RemotePort { get; }
  public string URI { get; }
  public string URIHost { get; }
  public int URIPort { get; }
  public string URIPath { get; }
  public string URIQuery { get; }
  public string Token { get; }  public byte[] TokenB { get; }
  public bool Accept { get; set; }
}
```

## Remarks

This event fires anytime a client wishes to register itself as an observer for the resource identified by *URI*. Refer to the [StartObserving](#startobserving-method-coap-component) and [SendNotification](#sendnotification-method-coap-component) methods, as well as the [Notification](#notification-event-coap-component) event, for more information about observing resources and resource change notifications.

Any options included in the request can be obtained by querying the [RequestOptions](#requestoptions-property-coap-component) collection.

To correctly handle this event, populate the [ResponseCode](#responsecode-property-coap-component), [ResponseData](#responsedata-property-coap-component), [ResponseContentFormat](#responsecontentformat-property-coap-component), [ResponseETag](#responseetag-property-coap-component), and [ResponseOptions](#responseoptions-property-coap-component) properties as desired before this event finishes. (This must be done regardless of the *Accept* parameter's final value; see below for more information on why).

The *RemoteHost* parameter reflects the client's IP address or hostname.

The *RemotePort* parameter reflects the client's port.

The *URI* parameter reflects the exact resource URI that the client wishes to observe (the CoAP specification states that the full URI must be used to track observers). This value must be passed exactly as-is to the [SendNotification](#sendnotification-method-coap-component) method to notify observers of changes to the resource.

The *URIHost*, *URIPort*, *URIPath*, and *URIQuery* parameters are provided for additional convenience

The *Token* parameter reflects the token included in the registration request.

The *Accept* parameter specifies whether the component should accept the registration. By default, it is *False*, and the request will be treated like a normal GET request. Setting it to *True* will cause the component to add the client to its internal list of registered observers for the specified *URI*.

Note: This event is only used when the component is operating in server mode (i.e., when the [Listening](#listening-property-coap-component) property is enabled).

# Request Event ([CoAP](#coap-component) Component)

Fires when a request is received from a client.

## Syntax

```text
public event OnRequestHandler OnRequest;

public delegate void OnRequestHandler(object sender, CoAPRequestEventArgs e);

public class CoAPRequestEventArgs : EventArgs {
  public string RemoteHost { get; }
  public int RemotePort { get; }
  public int Method { get; }
  public string URIHost { get; }
  public int URIPort { get; }
  public string URIPath { get; }
  public string URIQuery { get; }
  public string Token { get; }  public byte[] TokenB { get; }
  public string RequestId { get; }
  public bool SendResponse { get; set; }
}
```

## Remarks

This event fires anytime a request is received from a client. Information about the request is exposed both via this event's parameters and the following properties: [RequestData](#requestdata-property-coap-component), [RequestContentFormat](#requestcontentformat-property-coap-component), [RequestETag](#requestetag-property-coap-component), and [RequestOptions](#requestoptions-property-coap-component).

A response can either be sent back to the client immediately when the event finishes, or later using the [SendResponse](#sendresponse-method-coap-component) method. Refer to the *RequestId* and *SendResponse* parameters' documentation, below, for more information. If a response is to be sent back immediately, populate the [ResponseCode](#responsecode-property-coap-component), [ResponseData](#responsedata-property-coap-component), [ResponseContentFormat](#responsecontentformat-property-coap-component), [ResponseETag](#responseetag-property-coap-component), and [ResponseOptions](#responseoptions-property-coap-component) properties as desired before this event finishes.

The *RemoteHost* parameter reflects the client's IP address or hostname.

The *RemotePort* parameter reflects the client's port.

The *Method* parameter reflects the request method code. The following table provides a (non-exhaustive) list of some of the more common method codes; refer to the IANA's [CoAP Method Codes](https://www.iana.org/assignments/core-parameters/core-parameters.xhtml#method-codes) registry for a full list.

| Method Code | Name |
| --- | --- |
| 1 | GET |
| 2 | POST |
| 3 | PUT |
| 4 | DELETE |
| 5 | FETCH |
| 6 | PATCH |

The *URIHost*, *URIPort*, *URIPath*, and *URIQuery* parameters, when taken together, identify the resource that the client is making a request against. This event exposes the URI in pieces for convenience.

The *Token* parameter reflects the token included in the request.

The *RequestId* parameter reflects the component-generated Id for the request. If the final value of the *SendResponse* parameter is *False*, this Id can be passed to the [SendResponse](#sendresponse-method-coap-component) method later to send a response. (Alternatively, it can be passed to the [CancelRequest](#cancelrequest-method-coap-component) later to ignore the request.)

The *SendResponse* parameter specifies whether the component should send a response back to the client immediately; it is *True* by default. Set it to *False* to send the response later instead.

Note: This event is only used when the component is operating in server mode (i.e., when the [Listening](#listening-property-coap-component) property is enabled).

# RequestComplete Event ([CoAP](#coap-component) Component)

Fires when a request completes.

## Syntax

```text
public event OnRequestCompleteHandler OnRequestComplete;

public delegate void OnRequestCompleteHandler(object sender, CoAPRequestCompleteEventArgs e);

public class CoAPRequestCompleteEventArgs : EventArgs {
  public int Method { get; }
  public string URI { get; }
  public string RequestId { get; }
  public int ErrorCode { get; }
  public string ErrorDescription { get; }
}
```

## Remarks

This event fires when a request completes. Usually, a request is considered complete when a response has been received. However, requests can also be considered "complete" if either of the following occurs:

- If the [UseConfirmableMessages](#useconfirmablemessages-property-coap-component) property is enabled, and the component did not receive confirmation that the request was received before the retransmission period elapsed.
- If [Timeout](#timeout-property-coap-component) property is greater than *0*, and the component did not receive a response before the timeout period elapsed.

Assuming a response *was* received (i.e., the *ErrorCode* parameter is either *0* or *709*; see below), then the response code, payload, and options can be obtained by querying the [ResponseCode](#responsecode-property-coap-component), [ResponseData](#responsedata-property-coap-component), [ResponseContentFormat](#responsecontentformat-property-coap-component), [ResponseETag](#responseetag-property-coap-component), and [ResponseOptions](#responseoptions-property-coap-component) properties.

The *Method* parameter reflects the request method code. The following table provides a (non-exhaustive) list of some of the more common method codes; refer to the IANA's [CoAP Method Codes](https://www.iana.org/assignments/core-parameters/core-parameters.xhtml#method-codes) registry for a full list.

| Method Code | Name |
| --- | --- |
| 1 | GET |
| 2 | POST |
| 3 | PUT |
| 4 | DELETE |
| 5 | FETCH |
| 6 | PATCH |

The *URI* parameter reflects the requested resource's URI.

The *ErrorCode* parameter indicates whether the request encountered an error. If no error was encountered, it will be *0*; if the server returned a non-2.xx response code, it will be *709*; if some other error occurred (e.g., the request timed out), it will be another non-zero value.

The *ErrorDescription* parameter provides a description of the error that occurred (or, if *ErrorCode* is *709*, a string version of the response code returned by the server). It will be empty if no error was encountered.

Note: This event is only used when the component is operating in client mode (i.e., when the [Listening](#listening-property-coap-component) property is disabled).

# ResponseComplete Event ([CoAP](#coap-component) Component)

Fires when a response has been sent to a client.

## Syntax

```text
public event OnResponseCompleteHandler OnResponseComplete;

public delegate void OnResponseCompleteHandler(object sender, CoAPResponseCompleteEventArgs e);

public class CoAPResponseCompleteEventArgs : EventArgs {
  public string RequestId { get; }
  public int ErrorCode { get; }
  public string ErrorDescription { get; }
}
```

## Remarks

This event fires anytime a response has been sent to a client. If the [UseConfirmableMessages](#useconfirmablemessages-property-coap-component) property is enabled, then the response is considered complete once the client has confirmed that it received the response (or once the retransmission period elapses). If the [UseConfirmableMessages](#useconfirmablemessages-property-coap-component) property is disabled, the response is considered complete immediately (since there is no way to know if the client received it).

The *RequestId* parameter reflects the component-generated Id of the request for which the response was sent.

The *ErrorCode* parameter indicates whether the response encountered an error (e.g., transmission timed out). If no error was encountered, it will be *0*.

The *ErrorDescription* parameter provides a description of the error that occurred. It will be empty if no error was encountered.

Note: This event is only used when the component is operating in server mode (i.e., when the [Listening](#listening-property-coap-component) property is enabled).

# SSLClientAuthentication Event ([CoAP](#coap-component) Component)

This event is fired when the client presents its credentials to the server.

## Syntax

```text
public event OnSSLClientAuthenticationHandler OnSSLClientAuthentication;

public delegate void OnSSLClientAuthenticationHandler(object sender, CoAPSSLClientAuthenticationEventArgs e);

public class CoAPSSLClientAuthenticationEventArgs : EventArgs {
  public string ConnectionId { get; }
  public string CertEncoded { get; }  public byte[] CertEncodedB { get; }
  public string CertSubject { get; }
  public string CertIssuer { get; }
  public string Status { get; }
  public bool Accept { get; set; }
}
```

## Remarks

This event enables the server to decide whether or not to continue. The *Accept* parameter is a recommendation on whether to continue or to close the connection. This is just a suggestion: application software must use its own logic to determine whether or not to continue.

When *Accept* is False, *Status* shows why the verification failed (otherwise, *Status* contains the string "OK").

# SSLServerAuthentication Event ([CoAP](#coap-component) Component)

Fired after the server presents its certificate to the client.

## Syntax

```text
public event OnSSLServerAuthenticationHandler OnSSLServerAuthentication;

public delegate void OnSSLServerAuthenticationHandler(object sender, CoAPSSLServerAuthenticationEventArgs e);

public class CoAPSSLServerAuthenticationEventArgs : EventArgs {
  public string CertEncoded { get; }  public byte[] CertEncodedB { get; }
  public string CertSubject { get; }
  public string CertIssuer { get; }
  public string Status { get; }
  public bool Accept { get; set; }
}
```

## Remarks

During this event, the client can decide whether or not to continue with the connection process. The *Accept* parameter is a recommendation on whether to continue or close the connection. This is just a suggestion: application software must use its own logic to determine whether or not to continue.

 When *Accept* is False, *Status* shows why the verification failed (otherwise, *Status* contains the string *OK*). If it is decided to continue, you can override and accept the certificate by setting the *Accept* parameter to True.

# SSLStatus Event ([CoAP](#coap-component) Component)

Fired when secure connection progress messages are available.

## Syntax

```text
public event OnSSLStatusHandler OnSSLStatus;

public delegate void OnSSLStatusHandler(object sender, CoAPSSLStatusEventArgs e);

public class CoAPSSLStatusEventArgs : EventArgs {
  public string Message { get; }
}
```

## Remarks

The event is fired for informational and logging purposes only. This event tracks the progress of the connection.

# Unregistered Event ([CoAP](#coap-component) Component)

Fires when a client has unregistered from notifications.

## Syntax

```text
public event OnUnregisteredHandler OnUnregistered;

public delegate void OnUnregisteredHandler(object sender, CoAPUnregisteredEventArgs e);

public class CoAPUnregisteredEventArgs : EventArgs {
  public string RemoteHost { get; }
  public int RemotePort { get; }
  public string URI { get; }
  public string URIHost { get; }
  public int URIPort { get; }
  public string URIPath { get; }
  public string URIQuery { get; }
}
```

## Remarks

This event fires anytime a client has unregistered itself from further notifications for the resource identified by *URI*. Refer to the [StartObserving](#startobserving-method-coap-component) and [SendNotification](#sendnotification-method-coap-component) methods, as well as the [Notification](#notification-event-coap-component) and [Register](#register-event-coap-component) events, for more information about observing resources and resource change notifications.

The *RemoteHost* parameter reflects the client's IP address or hostname.

The *RemotePort* parameter reflects the client's port.

The *URI* parameter identifies the resource that the client has stopped observing.

The *URIHost*, *URIPort*, *URIPath*, and *URIQuery* parameters are provided for additional convenience

Note: This event is only used when the component is operating in server mode (i.e., when the [Listening](#listening-property-coap-component) property is enabled).

# Certificate Type

This is the digital certificate being used.

## Remarks

This type describes the current digital certificate. The certificate may be a public or private key. The fields are used to identify or select certificates.

The following fields are available:

- [EffectiveDate](#Certificate_f_EffectiveDate)

- [ExpirationDate](#Certificate_f_ExpirationDate)

- [ExtendedKeyUsage](#Certificate_f_ExtendedKeyUsage)

- [Fingerprint](#Certificate_f_Fingerprint)

- [FingerprintSHA1](#Certificate_f_FingerprintSHA1)

- [FingerprintSHA256](#Certificate_f_FingerprintSHA256)

- [Issuer](#Certificate_f_Issuer)

- [PrivateKey](#Certificate_f_PrivateKey)

- [PrivateKeyAvailable](#Certificate_f_PrivateKeyAvailable)

- [PrivateKeyContainer](#Certificate_f_PrivateKeyContainer)

- [PublicKey](#Certificate_f_PublicKey)

- [PublicKeyAlgorithm](#Certificate_f_PublicKeyAlgorithm)

- [PublicKeyLength](#Certificate_f_PublicKeyLength)

- [SerialNumber](#Certificate_f_SerialNumber)

- [SignatureAlgorithm](#Certificate_f_SignatureAlgorithm)

- [Store](#Certificate_f_Store)

- [StorePassword](#Certificate_f_StorePassword)

- [StoreType](#Certificate_f_StoreType)

- [SubjectAltNames](#Certificate_f_SubjectAltNames)

- [ThumbprintMD5](#Certificate_f_ThumbprintMD5)

- [ThumbprintSHA1](#Certificate_f_ThumbprintSHA1)

- [ThumbprintSHA256](#Certificate_f_ThumbprintSHA256)

- [Usage](#Certificate_f_Usage)

- [UsageFlags](#Certificate_f_UsageFlags)

- [Version](#Certificate_f_Version)

- [Subject](#Certificate_f_Subject)

- [Encoded](#Certificate_f_Encoded)

## Fields

 **EffectiveDate** *string (read-only)*
Default: ""

The date on which this certificate becomes valid. Before this date, it is not valid. The date is localized to the system's time zone. The following example illustrates the format of an encoded date:

23-Jan-2000 15:00:00.

 **ExpirationDate** *string (read-only)*
Default: ""

The date on which the certificate expires. After this date, the certificate will no longer be valid. The date is localized to the system's time zone. The following example illustrates the format of an encoded date:

23-Jan-2001 15:00:00.

 **ExtendedKeyUsage** *string (read-only)*
Default: ""

A comma-delimited list of extended key usage identifiers. These are the same as ASN.1 object identifiers (OIDs).

 **Fingerprint** *string (read-only)*
Default: ""

The hex-encoded, 16-byte MD5 fingerprint of the certificate. This property is primarily used for keys which do not have a corresponding X.509 public certificate, such as PEM keys that only contain a private key. It is commonly used for SSH keys.

The following example illustrates the format: *bc:2a:72:af:fe:58:17:43:7a:5f:ba:5a:7c:90:f7:02*

 **FingerprintSHA1** *string (read-only)*
Default: ""

The hex-encoded, 20-byte SHA-1 fingerprint of the certificate. This property is primarily used for keys which do not have a corresponding X.509 public certificate, such as PEM keys that only contain a private key. It is commonly used for SSH keys.

The following example illustrates the format: *30:7b:fa:38:65:83:ff:da:b4:4e:07:3f:17:b8:a4:ed:80:be:ff:84*

 **FingerprintSHA256** *string (read-only)*
Default: ""

The hex-encoded, 32-byte SHA-256 fingerprint of the certificate. This property is primarily used for keys which do not have a corresponding X.509 public certificate, such as PEM keys that only contain a private key. It is commonly used for SSH keys.

The following example illustrates the format: *6a:80:5c:33:a9:43:ea:b0:96:12:8a:64:96:30:ef:4a:8a:96:86:ce:f4:c7:be:10:24:8e:2b:60:9e:f3:59:53*

 **Issuer** *string (read-only)*
Default: ""

The issuer of the certificate. This field contains a string representation of the name of the issuing authority for the certificate.

 **PrivateKey** *string (read-only)*
Default: ""

The private key of the certificate (if available). The key is provided as PEM/Base64-encoded data.

NOTE: The [PrivateKey](#Certificate_f_PrivateKey) may be available but not exportable. In this case, [PrivateKey](#Certificate_f_PrivateKey) returns an empty string.

 **PrivateKeyAvailable** *bool (read-only)*
Default: False

Whether a [PrivateKey](#Certificate_f_PrivateKey) is available for the selected certificate. If [PrivateKeyAvailable](#Certificate_f_PrivateKeyAvailable) is True, the certificate may be used for authentication purposes (e.g., server authentication).

 **PrivateKeyContainer** *string (read-only)*
Default: ""

The name of the [PrivateKey](#Certificate_f_PrivateKey) container for the certificate (if available). This functionality is available only on Windows platforms.

 **PublicKey** *string (read-only)*
Default: ""

The public key of the certificate. The key is provided as PEM/Base64-encoded data.

 **PublicKeyAlgorithm** *string (read-only)*
Default: ""

The textual description of the certificate's public key algorithm. The property contains either the name of the algorithm (e.g., "RSA" or "RSA_DH") or an object identifier (OID) string representing the algorithm.

 **PublicKeyLength** *int (read-only)*
Default: 0

The length of the certificate's public key (in bits). Common values are 512, 1024, and 2048.

 **SerialNumber** *string (read-only)*
Default: ""

The serial number of the certificate encoded as a string. The number is encoded as a series of hexadecimal digits, with each pair representing a byte of the serial number.

 **SignatureAlgorithm** *string (read-only)*
Default: ""

The text description of the certificate's signature algorithm. The property contains either the name of the algorithm (e.g., "RSA" or "RSA_MD5RSA") or an object identifier (OID) string representing the algorithm.

 **Store** *string*
Default: "MY"

The name of the certificate store for the client certificate.

The [StoreType](#Certificate_f_StoreType) field denotes the type of the certificate store specified by [Store](#Certificate_f_Store). If the store is password-protected, specify the password in [StorePassword](#Certificate_f_StorePassword).

[Store](#Certificate_f_Store) is used in conjunction with the [Subject](#Certificate_f_Subject) field to specify client certificates. If [Store](#Certificate_f_Store) has a value, and [Subject](#Certificate_f_Subject) or [Encoded](#Certificate_f_Encoded) is set, a search for a certificate is initiated. Please see the [Subject](#Certificate_f_Subject) field for details.

 Designations of certificate stores are platform dependent.

The following designations are the most common User and Machine certificate stores in Windows:

|  |  |
| --- | --- |
| MY | A certificate store holding personal certificates with their associated private keys. |
| CA | Certifying authority certificates. |
| ROOT | Root certificates. |

When the certificate store type is *cstPFXFile*, this property must be set to the name of the file. When the type is *cstPFXBlob*, the property must be set to the binary contents of a PFX file (i.e., PKCS#12 certificate store).

 **StoreB** *byte []*
Default: "MY"

The name of the certificate store for the client certificate.

The [StoreType](#Certificate_f_StoreType) field denotes the type of the certificate store specified by [Store](#Certificate_f_Store). If the store is password-protected, specify the password in [StorePassword](#Certificate_f_StorePassword).

[Store](#Certificate_f_Store) is used in conjunction with the [Subject](#Certificate_f_Subject) field to specify client certificates. If [Store](#Certificate_f_Store) has a value, and [Subject](#Certificate_f_Subject) or [Encoded](#Certificate_f_Encoded) is set, a search for a certificate is initiated. Please see the [Subject](#Certificate_f_Subject) field for details.

 Designations of certificate stores are platform dependent.

The following designations are the most common User and Machine certificate stores in Windows:

|  |  |
| --- | --- |
| MY | A certificate store holding personal certificates with their associated private keys. |
| CA | Certifying authority certificates. |
| ROOT | Root certificates. |

When the certificate store type is *cstPFXFile*, this property must be set to the name of the file. When the type is *cstPFXBlob*, the property must be set to the binary contents of a PFX file (i.e., PKCS#12 certificate store).

 **StorePassword** *string*
Default: ""

If the type of certificate store requires a password, this field is used to specify the password needed to open the certificate store.

 **StoreType** *CertStoreTypes*
Default: 0

The type of certificate store for this certificate.

 The component supports both public and private keys in a variety of formats. When the *cstAuto* value is used, the component will automatically determine the type. This field can take one of the following values:

```csharp
sftp.SSHCert = new Certificate(CertStoreTypes.cstPKCS11,
                               @"C:\Program Files\OpenSC Project\OpenSC\pkcs11\opensc-pkcs11.dll",
                               "123456", // PIN
                               "CN=cert_subject");
sftp.SSHUser = "test";
sftp.SSHLogon("myhost", 22);
```

```csharp
certmgr.CertStoreType = CertStoreTypes.cstPKCS11;
certmgr.OnCertList += (s, e) => {
  secKeyBlob = e.CertEncoded;
};
certmgr.CertStore = @"C:\Program Files\OpenSC Project\OpenSC\pkcs11\opensc-pkcs11.dll";
certmgr.CertStorePassword = "123456"; // PIN
certmgr.ListStoreCertificates();

sftp.SSHCert = new Certificate(CertStoreTypes.cstPKCS11, secKeyBlob, "123456", "*");
sftp.SSHUser = "test";
sftp.SSHLogon("myhost", 22);
```

|  |  |
| --- | --- |
| 0 (cstUser - default) | For Windows, this specifies that the certificate store is a certificate store owned by the current user. NOTE: This store type is not available in Java. |
| 1 (cstMachine) | For Windows, this specifies that the certificate store is a machine store. NOTE: This store type is not available in Java. |
| 2 (cstPFXFile) | The certificate store is the name of a PFX (PKCS#12) file containing certificates. |
| 3 (cstPFXBlob) | The certificate store is a string (binary or Base64-encoded) representing a certificate store in PFX (PKCS#12) format. |
| 4 (cstJKSFile) | The certificate store is the name of a Java Key Store (JKS) file containing certificates. NOTE: This store type is only available in Java. |
| 5 (cstJKSBlob) | The certificate store is a string (binary or Base64-encoded) representing a certificate store in Java Key Store (JKS) format. NOTE: This store type is only available in Java. |
| 6 (cstPEMKeyFile) | The certificate store is the name of a PEM-encoded file that contains a private key and an optional certificate. |
| 7 (cstPEMKeyBlob) | The certificate store is a string (binary or Base64-encoded) that contains a private key and an optional certificate. |
| 8 (cstPublicKeyFile) | The certificate store is the name of a file that contains a PEM- or DER-encoded public key certificate. |
| 9 (cstPublicKeyBlob) | The certificate store is a string (binary or Base64-encoded) that contains a PEM- or DER-encoded public key certificate. |
| 10 (cstSSHPublicKeyBlob) | The certificate store is a string (binary or Base64-encoded) that contains an SSH-style public key. |
| 11 (cstP7BFile) | The certificate store is the name of a PKCS#7 file containing certificates. |
| 12 (cstP7BBlob) | The certificate store is a string (binary) representing a certificate store in PKCS#7 format. |
| 13 (cstSSHPublicKeyFile) | The certificate store is the name of a file that contains an SSH-style public key. |
| 14 (cstPPKFile) | The certificate store is the name of a file that contains a PPK (PuTTY Private Key). |
| 15 (cstPPKBlob) | The certificate store is a string (binary) that contains a PPK (PuTTY Private Key). |
| 16 (cstXMLFile) | The certificate store is the name of a file that contains a certificate in XML format. |
| 17 (cstXMLBlob) | The certificate store is a string that contains a certificate in XML format. |
| 18 (cstJWKFile) | The certificate store is the name of a file that contains a JWK (JSON Web Key). |
| 19 (cstJWKBlob) | The certificate store is a string that contains a JWK (JSON Web Key). |
| 21 (cstBCFKSFile) | The certificate store is the name of a file that contains a BCFKS (Bouncy Castle FIPS Key Store). NOTE: This store type is only available in Java and .NET. |
| 22 (cstBCFKSBlob) | The certificate store is a string (binary or Base64-encoded) representing a certificate store in BCFKS (Bouncy Castle FIPS Key Store) format. NOTE: This store type is only available in Java and .NET. |
| 23 (cstPKCS11) | The certificate is present on a physical security key accessible via a PKCS#11 interface. To use a security key, create a new [Certificate](#certificate-type) object and pass cstPKCS11 as the [StoreType](#Certificate_f_StoreType), the full path of the PKCS#11 DLL as the [Store](#Certificate_f_Store), and the PIN as the [StorePassword](#Certificate_f_StorePassword). Code Example. SSH Authentication with Security Key (without CertMgr): Alternatively, collect the necessary data using the [CertMgr](CertMgr.md#CertMgr) component by calling the [ListStoreCertificates](CertMgr.md#CertMgr_m_ListStoreCertificates) method after setting the corresponding properties accordingly. The certificate information returned in the [CertList](CertMgr.md#CertMgr_e_CertList) event's CertEncoded parameter may be saved for later use. When using a certificate obtained with this approach, pass the previously saved security key information as the [Store](#Certificate_f_Store) and set [StorePassword](#Certificate_f_StorePassword) to the PIN. Code Example. SSH Authentication with Security Key (with CertMgr): |
| 99 (cstAuto) | The store type is automatically detected from the input data. This setting may be used with both public and private keys and can detect any of the supported formats automatically. |

 **SubjectAltNames** *string (read-only)*
Default: ""

Comma-separated lists of alternative subject names for the certificate.

 **ThumbprintMD5** *string (read-only)*
Default: ""

The MD5 hash of the certificate. It is primarily used for X.509 certificates. If the hash does not already exist, it is automatically computed.

 **ThumbprintSHA1** *string (read-only)*
Default: ""

The SHA-1 hash of the certificate. It is primarily used for X.509 certificates. If the hash does not already exist, it is automatically computed.

 **ThumbprintSHA256** *string (read-only)*
Default: ""

The SHA-256 hash of the certificate. It is primarily used for X.509 certificates. If the hash does not already exist, it is automatically computed.

 **Usage** *string (read-only)*
Default: ""

The text description of [UsageFlags](#Certificate_f_UsageFlags).

This value will be one or more of the following strings and will be separated by commas:

- Digital Signature
- Non-Repudiation
- Key Encipherment
- Data Encipherment
- Key Agreement
- Certificate Signing
- CRL Signing
- Encipher Only

If the provider is OpenSSL, the value is a comma-separated list of X.509 certificate extension names.

 **UsageFlags** *int (read-only)*
Default: 0

The flags that show intended use for the certificate. The value of [UsageFlags](#Certificate_f_UsageFlags) is a combination of the following flags:

|  |  |
| --- | --- |
| 0x80 | Digital Signature |
| 0x40 | Non-Repudiation |
| 0x20 | Key Encipherment |
| 0x10 | Data Encipherment |
| 0x08 | Key Agreement |
| 0x04 | Certificate Signing |
| 0x02 | CRL Signing |
| 0x01 | Encipher Only |

Please see the [Usage](#Certificate_f_Usage) field for a text representation of [UsageFlags](#Certificate_f_UsageFlags).

This functionality currently is not available when the provider is OpenSSL.

 **Version** *string (read-only)*
Default: ""

The certificate's version number. The possible values are the strings "V1", "V2", and "V3".

 **Subject** *string*
Default: ""

The subject of the certificate used for client authentication.

This field will be populated with the full subject of the loaded certificate. When loading a certificate, the subject is used to locate the certificate in the store.

If an exact match is not found, the store is searched for subjects containing the value of the property.

If a match is still not found, the property is set to an empty string, and no certificate is selected.

The special value "*" picks a random certificate in the certificate store.

The certificate subject is a comma-separated list of distinguished name fields and values. For instance, "CN=www.server.com, OU=test, C=US, E=example@email.com". Common fields and their meanings are as follows:

| Field | Meaning |
| --- | --- |
| CN | Common Name. This is commonly a hostname like www.server.com. |
| O | Organization |
| OU | Organizational Unit |
| L | Locality |
| S | State |
| C | Country |
| E | Email Address |

If a field value contains a comma, it must be quoted.

 **Encoded** *string*
Default: ""

The certificate (PEM/Base64 encoded). This field is used to assign a specific certificate. The [Store](#Certificate_f_Store) and [Subject](#Certificate_f_Subject) fields also may be used to specify a certificate.

When [Encoded](#Certificate_f_Encoded) is set, a search is initiated in the current [Store](#Certificate_f_Store) for the private key of the certificate. If the key is found, [Subject](#Certificate_f_Subject) is updated to reflect the full subject of the selected certificate; otherwise, [Subject](#Certificate_f_Subject) is set to an empty string.

 **EncodedB** *byte []*
Default: ""

The certificate (PEM/Base64 encoded). This field is used to assign a specific certificate. The [Store](#Certificate_f_Store) and [Subject](#Certificate_f_Subject) fields also may be used to specify a certificate.

When [Encoded](#Certificate_f_Encoded) is set, a search is initiated in the current [Store](#Certificate_f_Store) for the private key of the certificate. If the key is found, [Subject](#Certificate_f_Subject) is updated to reflect the full subject of the selected certificate; otherwise, [Subject](#Certificate_f_Subject) is set to an empty string.

## Constructors

```text
public Certificate();
```

 Creates a instance whose properties can be set.

```text
public Certificate(string certificateFile);
```

 Opens * CertificateFile * and reads out the contents as an X.509 public key.

```text
public Certificate(byte[] encoded);
```

 Parses * Encoded * as an X.509 public key.

```text
public Certificate(CertStoreTypes storeType, string store, string storePassword, string subject);
```

 * StoreType * identifies the type of certificate store to use. See for descriptions of the different certificate stores. * Store * is a file containing the certificate store. * StorePassword * is the password used to protect the store.

 After the store has been successfully opened, the component will attempt to find the certificate identified by * Subject * . This can be either a complete or a substring match of the X.509 certificate's subject Distinguished Name (DN). The * Subject * parameter can also take an MD5, SHA-1, or SHA-256 thumbprint of the certificate to load in a "Thumbprint=value" format.

```text
public Certificate(CertStoreTypes storeType, string store, string storePassword, string subject, string configurationString);
```

 * StoreType * identifies the type of certificate store to use. See for descriptions of the different certificate stores. * Store * is a file containing the certificate store. * StorePassword * is the password used to protect the store.

 * ConfigurationString * is a newline-separated list of name-value pairs that may be used to modify the default behavior. Possible values include "PersistPFXKey", which shows whether or not the PFX key is persisted after performing operations with the private key. This correlates to the PKCS12_NO_PERSIST_KEY CryptoAPI option. The default value is True (the key is persisted). "Thumbprint" - an MD5, SHA-1, or SHA-256 thumbprint of the certificate to load. When specified, this value is used to select the certificate in the store. This is applicable to the * cstUser * , * cstMachine * , * cstPublicKeyFile * , and * cstPFXFile * store types. "UseInternalSecurityAPI" shows whether the platform (default) or the internal security API is used when performing certificate-related operations.

 After the store has been successfully opened, the component will attempt to find the certificate identified by * Subject * . This can be either a complete or a substring match of the X.509 certificate's subject Distinguished Name (DN). The * Subject * parameter can also take an MD5, SHA-1, or SHA-256 thumbprint of the certificate to load in a "Thumbprint=value" format.

```text
public Certificate(CertStoreTypes storeType, string store, string storePassword, byte[] encoded);
```

 * StoreType * identifies the type of certificate store to use. See for descriptions of the different certificate stores. * Store * is a file containing the certificate store. * StorePassword * is the password used to protect the store.

 After the store has been successfully opened, the component will load * Encoded * as an X.509 certificate and search the opened store for a corresponding private key.

```text
public Certificate(CertStoreTypes storeType, byte[] store, string storePassword, string subject);
```

 * StoreType * identifies the type of certificate store to use. See for descriptions of the different certificate stores. * Store * is a byte array containing the certificate data. * StorePassword * is the password used to protect the store.

 After the store has been successfully opened, the component will attempt to find the certificate identified by * Subject * . This can be either a complete or a substring match of the X.509 certificate's subject Distinguished Name (DN). The * Subject * parameter can also take an MD5, SHA-1, or SHA-256 thumbprint of the certificate to load in a "Thumbprint=value" format.

```text
public Certificate(CertStoreTypes storeType, byte[] store, string storePassword, string subject, string configurationString);
```

 * StoreType * identifies the type of certificate store to use. See for descriptions of the different certificate stores. * Store * is a byte array containing the certificate data. * StorePassword * is the password used to protect the store.

 After the store has been successfully opened, the component will attempt to find the certificate identified by * Subject * . This can be either a complete or a substring match of the X.509 certificate's subject Distinguished Name (DN). The * Subject * parameter can also take an MD5, SHA-1, or SHA-256 thumbprint of the certificate to load in a "Thumbprint=value" format.

```text
public Certificate(CertStoreTypes storeType, byte[] store, string storePassword, byte[] encoded);
```

 * StoreType * identifies the type of certificate store to use. See for descriptions of the different certificate stores. * Store * is a byte array containing the certificate data. * StorePassword * is the password used to protect the store.

 After the store has been successfully opened, the component will load * Encoded * as an X.509 certificate and search the opened store for a corresponding private key.

# CoAPOption Type

A CoAP option.

## Remarks

This type represents a CoAP option.

The following fields are available:

- [Critical](#CoAPOption_f_Critical)

- [NoCacheKey](#CoAPOption_f_NoCacheKey)

- [Number](#CoAPOption_f_Number)

- [Unsafe](#CoAPOption_f_Unsafe)

- [Value](#CoAPOption_f_Value)

- [ValueType](#CoAPOption_f_ValueType)

## Fields

 **Critical** *bool (read-only)*
Default: False

Whether the option is critical.

This field reflects whether the option is critical or elective. Receivers that do not recognize a critical option must return a *4.02* "Bad Option" response code back to the sender. Unrecognized elective options can be safely ignored.

 **NoCacheKey** *bool (read-only)*
Default: False

Whether the option is to be excluded from the cache-key.

This field reflects whether the option should be excluded from any cache-key calculations. This information is generally only needed for caching and proxying.

 **Number** *int*
Default: 0

The option's number.

The field reflects the option's number, which must be a value in the range *0* to *65535* (inclusive). Setting this field to a recognized option number (see table below) will automatically set the [ValueType](#CoAPOption_f_ValueType) field to the correct value (it should be set manually otherwise).

The following table provides a (non-exhaustive) list of some of the more common option numbers; refer to the IANA's [CoAP Option Numbers](https://www.iana.org/assignments/core-parameters/core-parameters.xhtml#option-numbers) registry for a full list.

| Number | Option |
| --- | --- |
| 1 | If-Match |
| 3 | Uri-Host |
| 4 | ETag |
| 5 | If-None-Match |
| 6 | Observe |
| 7 | Uri-Port |
| 8 | Location-Path |
| 11 | Uri-Path |
| 12 | Content-Format |
| 14 | Max-Age |
| 15 | Uri-Query |
| 17 | Accept |
| 20 | Location-Query |
| 23 | Block2 |
| 27 | Block1 |
| 35 | Proxy-Uri |
| 39 | Proxy-Scheme |
| 60 | Size1 |

 **Unsafe** *bool (read-only)*
Default: False

Whether the option is unsafe to forward.

This field reflects whether the option is unsafe to forward. This information is generally only needed for proxying.

 **Value** *string*
Default: ""

The option's value.

This field specifies the option's value. The [ValueType](#CoAPOption_f_ValueType) field specifies the data type of the value.

 **ValueType** *CoAPOptionValueTypes*
Default: 0

The option's value data type.

This field specifies the data type of the option's [Value](#CoAPOption_f_Value). If [Number](#CoAPOption_f_Number) is set to a recognized value (refer to the table in its documentation), this field will automatically be set to the correct value. The table below shows the possible value types, their descriptions, and how to format the data assigned to [Value](#CoAPOption_f_Value).

| Type | Description | Value Format |
| --- | --- | --- |
| ovtString (0) (default) | String | String |
| ovtUInt (1) | Unsigned integer | 0 to 4294967295 |
| ovtBinary (2) | Binary data | Hex-encoded byte string |

## Constructors

```text
public CoAPOption();
```

```text
public CoAPOption(int number, string value);
```

# CoAPRequest Type

A pending CoAP request.

## Remarks

This type represents a pending CoAP request.

The following fields are available:

- [Method](#CoAPRequest_f_Method)

- [RemoteHost](#CoAPRequest_f_RemoteHost)

- [RemotePort](#CoAPRequest_f_RemotePort)

- [RequestId](#CoAPRequest_f_RequestId)

- [Token](#CoAPRequest_f_Token)

- [URI](#CoAPRequest_f_URI)

## Fields

 **Method** *int (read-only)*
Default: 0

The request's method.

This field reflects the request's method code, which must be a value in the range *0* to *31*. The following table provides a (non-exhaustive) list of some of the more common method codes; refer to the IANA's [CoAP Method Codes](https://www.iana.org/assignments/core-parameters/core-parameters.xhtml#method-codes) registry for a full list.

| Method Code | Name |
| --- | --- |
| 1 | GET |
| 2 | POST |
| 3 | PUT |
| 4 | DELETE |
| 5 | FETCH |
| 6 | PATCH |

 **RemoteHost** *string (read-only)*
Default: ""

The remote host associated with the request.

This field reflects the remote host associated with the request. When the component is operating in client mode (i.e., the Listening property is disabled), this is the remote host to which the request was sent; when the component is operating in server mode (i.e., the Listening property is enabled), this is the remote host from which the request was received.

 **RemotePort** *int (read-only)*
Default: 0

The remote port associated with the request.

This field reflects the remote port associated with the request. Refer to the [RemoteHost](#CoAPRequest_f_RemoteHost) field's documentation for more information.

 **RequestId** *string (read-only)*
Default: ""

The request's Id.

This field reflects the request's component-generated Id.

 **Token** *string (read-only)*
Default: ""

The request's token.

This field reflects the request's token.

 **TokenB** *byte [] (read-only)*
Default: ""

The request's token.

This field reflects the request's token.

 **URI** *string (read-only)*
Default: ""

The request URI.

This field reflects the request's URI.

# Config Settings ([CoAP](#coap-component) Component)

 The component accepts one or more of the following *configuration settings*. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these *internal properties* is provided through the [Config](#config-method-coap-component) method.

### CoAP Config Settings

**MessageId**: Sets the MessageId for a request.The component will generate a MessageId automatically. This can be queried before sending a message or set to a value of your choice.

**UseEmptyToken**: Uses an empty value for the request token.Set this to *true* to use an empty token value for requests. Set to *false* by default.

**UseRawPublicKey**: Whether to enable Raw Public Key mode.When DTLS is enabled via [SSLEnabled](#sslenabled-property-coap-component), the component supports Certificate mode DTLS as defined by RFC 7252. Set this to *true* to use Raw Public Key mode instead.

### SSL Config Settings

**CACertFilePaths**: The paths to CA certificate files when using Mono on Unix/Linux.This configuration setting specifies the paths on disk to certificate authority (CA) certificate files when using Mono on Unix/Linux. It is not applicable in any other circumstances.

The value is formatted as a list of paths separated by semicolons. The component will check for the existence of each file in the order specified. When a file is found, the CA certificates within the file will be loaded and used to determine the validity of server or client certificates.

The default value is as follows:

*/etc/ssl/ca-bundle.pem;/etc/pki/tls/certs/ca-bundle.crt;/etc/ssl/certs/ca-certificates.crt;/etc/pki/tls/cacert.pem*

**LogSSLPackets**: Controls whether SSL packets are logged when using the internal security API.When SSLProvider is set to *Internal*, this configuration setting controls whether Secure Sockets Layer (SSL) packets should be logged. By default, this configuration setting is *False*, as it is useful only for debugging purposes.

When enabled, SSL packet logs are output using the [SSLStatus](#sslstatus-event-coap-component) event, which will fire each time an SSL packet is sent or received.

Enabling this configuration setting has no effect if SSLProvider is set to *Platform*.

**ReuseSSLSession**: Determines if the SSL session is reused.

If set to True, the component will reuse the context if and only if the following criteria are met:

- The target host name is the same.
- The system cache entry has not expired (default timeout is 10 hours).
- The application process that calls the function is the same.
- The logon session is the same.
- The instance of the component is the same.

**SSLCACerts**: A newline separated list of CA certificates to be included when performing an SSL handshake.When SSLProvider is set to *Internal*, this configuration setting specifies one or more CA certificates to be included with the [SSLCert](#sslcert-property-coap-component) property. Some servers or clients require the entire chain, including CA certificates, to be presented when performing SSL authentication. The value of this configuration setting is a newline-separated (CR/LF) list of certificates. For instance:

```text
-----BEGIN CERTIFICATE-----
MIIEKzCCAxOgAwIBAgIRANTET4LIkxdH6P+CFIiHvTowDQYJKoZIhvcNAQELBQAw
... Intermediate Cert ...
eWHV5OW1K53o/atv59sOiW5K3crjFhsBOd5Q+cJJnU+SWinPKtANXMht+EDvYY2w
F0I1XhM+pKj7FjDr+XNj
-----END CERTIFICATE-----
\r \n
-----BEGIN CERTIFICATE-----
MIIEFjCCAv6gAwIBAgIQetu1SMxpnENAnnOz1P+PtTANBgkqhkiG9w0BAQUFADBp
... Root Cert ...
d8q23djXZbVYiIfE9ebr4g3152BlVCHZ2GyPdjhIuLeH21VbT/dyEHHA
-----END CERTIFICATE-----
```

**SSLCheckCRL**: Whether to check the Certificate Revocation List for the server certificate.This configuration setting specifies whether the component will check the Certificate Revocation List (CRL) specified by the server certificate. If set to 1 or 2, the component will first obtain the list of CRL URLs from the server certificate's CRL distribution points extension. The component will then make HTTP requests to each CRL endpoint to check the validity of the server's certificate. If the certificate has been revoked or any other issues are found during validation the component throws an exception.

When set to 0 (default), the CRL check will not be performed by the component. When set to 1, it will attempt to perform the CRL check, but it will continue without an error if the server's certificate does not support CRL. When set to 2, it will perform the CRL check and will throw an error if CRL is not supported.

This configuration setting is supported only in the Java, C#, and C++ editions. In the C++ edition, it is supported only on Windows operating systems.

**SSLCheckOCSP**: Whether to use OCSP to check the status of the server certificate.This configuration setting specifies whether the component will use OCSP to check the validity of the server certificate. If set to 1 or 2, the component will first obtain the Online Certificate Status Protocol (OCSP) URL from the server certificate's OCSP extension. The component will then locate the issuing certificate and make an HTTP request to the OCSP endpoint to check the validity of the server's certificate. If the certificate has been revoked or any other issues are found during validation, the component throws an exception.

When set to 0 (default), the component will not perform an OCSP check. When set to 1, it will attempt to perform the OCSP check, but it will continue without an error if the server's certificate does not support OCSP. When set to 2, it will perform the OCSP check and will throw an error if OCSP is not supported.

This configuration setting is supported only in the Java, C#, and C++ editions. In the C++ edition, it is supported only on Windows operating systems.

**SSLCipherStrength**: The minimum cipher strength used for bulk encryption. This minimum cipher strength is largely dependent on the security modules installed on the system. If the cipher strength specified is not supported, an error will be returned when connections are initiated.

NOTE: This configuration setting contains the minimum cipher strength requested from the security library. The actual cipher strength used for the connection is shown by the [SSLStatus](#sslstatus-event-coap-component) event.

Use this configuration setting with caution. Requesting a lower cipher strength than necessary could potentially cause serious security vulnerabilities in your application.

When the provider is OpenSSL, [SSLCipherStrength](#SSLCipherStrength) is currently not supported. This functionality is instead made available through the [OpenSSLCipherList](#OpenSSLCipherList) configuration setting.

**SSLClientCACerts**: A newline separated list of CA certificates to use during SSL client certificate validation.This configuration setting is only applicable to server components (e.g., TCPServer) see [SSLServerCACerts](#SSLServerCACerts) for client components (e.g., TCPClient). This setting can be used to optionally specify one or more CA certificates to be used when verifying the client certificate that is presented by the client during the SSL handshake when [SSLAuthenticateClients](#sslauthenticateclients-property-coap-component) is enabled. When verifying the client's certificate, the certificates trusted by the system will be used as part of the verification process. If the client's CA certificates are not installed to the trusted system store, they may be specified here so they are included when performing the verification process. This configuration setting should be set only if the client's CA certificates are not already trusted on the system and cannot be installed to the trusted system store.

The value of this configuration setting is a newline-separated (CR/LF) list of certificates. For instance:

```text
-----BEGIN CERTIFICATE-----
MIIEKzCCAxOgAwIBAgIRANTET4LIkxdH6P+CFIiHvTowDQYJKoZIhvcNAQELBQAw
... Intermediate Cert ...
eWHV5OW1K53o/atv59sOiW5K3crjFhsBOd5Q+cJJnU+SWinPKtANXMht+EDvYY2w
F0I1XhM+pKj7FjDr+XNj
-----END CERTIFICATE-----
\r \n
-----BEGIN CERTIFICATE-----
MIIEFjCCAv6gAwIBAgIQetu1SMxpnENAnnOz1P+PtTANBgkqhkiG9w0BAQUFADBp
... Root Cert ...
d8q23djXZbVYiIfE9ebr4g3152BlVCHZ2GyPdjhIuLeH21VbT/dyEHHA
-----END CERTIFICATE-----
```

**SSLEnabledCipherSuites**: The cipher suite to be used in an SSL negotiation.This configuration setting enables the cipher suites to be used in SSL negotiation.

By default, the enabled cipher suites will include all available ciphers ("*").

The special value "*" means that the component will pick all of the supported cipher suites. If [SSLEnabledCipherSuites](#SSLEnabledCipherSuites) is set to any other value, only the specified cipher suites will be considered.

Multiple cipher suites are separated by semicolons.

Example values when SSLProvider is set to *Platform* include the following:

```text
obj.config("SSLEnabledCipherSuites=*");
obj.config("SSLEnabledCipherSuites=CALG_AES_256");
obj.config("SSLEnabledCipherSuites=CALG_AES_256;CALG_3DES");
```

 Possible values when SSLProvider is set to *Platform* include the following:

- CALG_3DES
- CALG_3DES_112
- CALG_AES
- CALG_AES_128
- CALG_AES_192
- CALG_AES_256
- CALG_AGREEDKEY_ANY
- CALG_CYLINK_MEK
- CALG_DES
- CALG_DESX
- CALG_DH_EPHEM
- CALG_DH_SF
- CALG_DSS_SIGN
- CALG_ECDH
- CALG_ECDH_EPHEM
- CALG_ECDSA
- CALG_ECMQV
- CALG_HASH_REPLACE_OWF
- CALG_HUGHES_MD5
- CALG_HMAC
- CALG_KEA_KEYX
- CALG_MAC
- CALG_MD2
- CALG_MD4
- CALG_MD5
- CALG_NO_SIGN
- CALG_OID_INFO_CNG_ONLY
- CALG_OID_INFO_PARAMETERS
- CALG_PCT1_MASTER
- CALG_RC2
- CALG_RC4
- CALG_RC5
- CALG_RSA_KEYX
- CALG_RSA_SIGN
- CALG_SCHANNEL_ENC_KEY
- CALG_SCHANNEL_MAC_KEY
- CALG_SCHANNEL_MASTER_HASH
- CALG_SEAL
- CALG_SHA
- CALG_SHA1
- CALG_SHA_256
- CALG_SHA_384
- CALG_SHA_512
- CALG_SKIPJACK
- CALG_SSL2_MASTER
- CALG_SSL3_MASTER
- CALG_SSL3_SHAMD5
- CALG_TEK
- CALG_TLS1_MASTER
- CALG_TLS1PRF

 Example values when SSLProvider is set to *Internal*include the following:

```text
obj.config("SSLEnabledCipherSuites=*");
obj.config("SSLEnabledCipherSuites=TLS_DHE_DSS_WITH_AES_128_CBC_SHA");
obj.config("SSLEnabledCipherSuites=TLS_DHE_DSS_WITH_AES_128_CBC_SHA;TLS_ECDH_RSA_WITH_AES_128_CBC_SHA");
```

 Possible values when SSLProvider is set to *Internal* include the following:

- TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
- TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
- TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
- TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
- TLS_ECDH_ECDSA_WITH_AES_256_GCM_SHA384
- TLS_RSA_WITH_AES_256_GCM_SHA384
- TLS_RSA_WITH_AES_128_GCM_SHA256
- TLS_ECDH_ECDSA_WITH_AES_128_GCM_SHA256
- TLS_DHE_DSS_WITH_AES_256_GCM_SHA384
- TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
- TLS_ECDH_RSA_WITH_AES_256_GCM_SHA384
- TLS_ECDH_RSA_WITH_AES_128_GCM_SHA256
- TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
- TLS_DHE_DSS_WITH_AES_128_GCM_SHA256
- TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384
- TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
- TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA384
- TLS_DHE_DSS_WITH_AES_256_CBC_SHA256
- TLS_RSA_WITH_AES_256_CBC_SHA256
- TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
- TLS_ECDH_RSA_WITH_AES_256_CBC_SHA384
- TLS_DHE_RSA_WITH_AES_256_CBC_SHA256
- TLS_DHE_RSA_WITH_AES_128_CBC_SHA256
- TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
- TLS_RSA_WITH_AES_128_CBC_SHA256
- TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA256
- TLS_ECDH_RSA_WITH_AES_128_CBC_SHA256
- TLS_DHE_DSS_WITH_AES_128_CBC_SHA256
- TLS_RSA_WITH_AES_256_CBC_SHA
- TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
- TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
- TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA
- TLS_DHE_RSA_WITH_AES_256_CBC_SHA
- TLS_ECDH_RSA_WITH_AES_256_CBC_SHA
- TLS_DHE_DSS_WITH_AES_256_CBC_SHA
- TLS_RSA_WITH_AES_128_CBC_SHA
- TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
- TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
- TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA
- TLS_ECDH_RSA_WITH_AES_128_CBC_SHA
- TLS_DHE_RSA_WITH_AES_128_CBC_SHA
- TLS_DHE_DSS_WITH_AES_128_CBC_SHA
- TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA
- TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA
- TLS_ECDH_ECDSA_WITH_3DES_EDE_CBC_SHA
- TLS_ECDH_RSA_WITH_3DES_EDE_CBC_SHA
- TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA
- TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA
- TLS_RSA_WITH_3DES_EDE_CBC_SHA
- TLS_RSA_WITH_DES_CBC_SHA
- TLS_DHE_RSA_WITH_DES_CBC_SHA
- TLS_DHE_DSS_WITH_DES_CBC_SHA
- TLS_RSA_WITH_RC4_128_MD5
- TLS_RSA_WITH_RC4_128_SHA

When TLS 1.3 is negotiated (see [SSLEnabledProtocols](#SSLEnabledProtocols)), only the following cipher suites are supported:

- TLS_AES_256_GCM_SHA384
- TLS_CHACHA20_POLY1305_SHA256
- TLS_AES_128_GCM_SHA256

[SSLEnabledCipherSuites](#SSLEnabledCipherSuites) is used together with [SSLCipherStrength](#SSLCipherStrength).

**SSLEnabledProtocols**: Used to enable/disable the supported security protocols.This configuration setting is used to enable or disable the supported security protocols.

Not all supported protocols are enabled by default. The default value is *4032* for client components, and *3072* for server components. To specify a combination of enabled protocol versions set this config to the binary *OR* of one or more of the following values:

|  |  |
| --- | --- |
| TLS1.3 | 12288 (Hex 3000) |
| TLS1.2 | 3072 (Hex C00) (Default - Client and Server) |
| TLS1.1 | 768 (Hex 300) (Default - Client) |
| TLS1 | 192 (Hex C0) (Default - Client) |
| SSL3 | 48 (Hex 30) |
| SSL2 | 12 (Hex 0C) |

Note that only TLS 1.2 is enabled for server components that accept incoming connections. This adheres to industry standards to ensure a secure connection. Client components enable TLS 1.0, TLS 1.1, and TLS 1.2 by default and will negotiate the highest mutually supported version when connecting to a server, which should be TLS 1.2 in most cases.

**SSLEnabledProtocols: Transport Layer Security (TLS) 1.3 Notes:**

By default when TLS 1.3 is enabled, the component will first try to use the platform TLS 1.3 implementation when the SSLProvider is set to Automatic for all editions. If the platform TLS 1.3 implementation is not available, the internal implementation will be used.

In editions that are designed to run on Windows, SSLProvider can be set to Platform to use the platform implementation instead of the internal implementation. When configured in this manner, please note that the platform provider is supported only on Windows 11/Windows Server 2022 and up. The default internal provider is available on all platforms and is not restricted to any specific OS version.

If set to *1* (Platform provider), please be aware of the following notes:

- The platform provider is available only on Windows 11/Windows Server 2022 and up.
- [SSLEnabledCipherSuites](#SSLEnabledCipherSuites) and other similar SSL configuration settings are not supported.
- If [SSLEnabledProtocols](#SSLEnabledProtocols) includes both TLS 1.3 and TLS 1.2, these restrictions are still applicable even if TLS 1.2 is negotiated. Enabling TLS 1.3 with the platform provider changes the implementation used for all TLS versions.

**SSLEnabledProtocols: SSL2 and SSL3 Notes: **

SSL 2.0 and 3.0 are not supported by the component when the SSLProvider is set to internal. To use SSL 2.0 or SSL 3.0, the platform security API must have the protocols enabled and SSLProvider needs to be set to platform.

**SSLEnableRenegotiation**: Whether the renegotiation_info SSL extension is supported.This configuration setting specifies whether the renegotiation_info SSL extension will be used in the request when using the internal security API. This configuration setting is *false* by default, but it can be set to *true* to enable the extension.

This configuration setting is applicable only when SSLProvider is set to *Internal*.

**SSLIncludeCertChain**: Whether the entire certificate chain is included in the SSLServerAuthentication event.This configuration setting specifies whether the Encoded parameter of the [SSLServerAuthentication](#sslserverauthentication-event-coap-component) event contains the full certificate chain. By default this value is False and only the leaf certificate will be present in the Encoded parameter of the [SSLServerAuthentication](#sslserverauthentication-event-coap-component) event.

If set to True, all certificates returned by the server will be present in the Encoded parameter of the [SSLServerAuthentication](#sslserverauthentication-event-coap-component) event. This includes the leaf certificate, any intermediate certificate, and the root certificate.

Note: When SSLProvider is set to *Internal* this value is automatically set to *true*. This is needed for proper validation when using the internal provider.

**SSLKeyLogFile**: The location of a file where per-session secrets are written for debugging purposes.This configuration setting optionally specifies the full path to a file on disk where per-session secrets are stored for debugging purposes.

When set, the component will save the session secrets in the same format as the SSLKEYLOGFILE environment variable functionality used by most major browsers and tools, such as Chrome, Firefox, and cURL. This file can then be used in tools such as Wireshark to decrypt TLS traffic for debugging purposes. When writing to this file, the component will only append, it will not overwrite previous values.

NOTE: This configuration setting is applicable only when SSLProvider is set to *Internal*.

**SSLNegotiatedCipher**: Returns the negotiated cipher suite.This configuration setting returns the cipher suite negotiated during the SSL handshake.

NOTE: For server components (e.g., TCPServer), this is a per-connection configuration setting accessed by passing the ConnectionId. For example:

```csharp
server.Config("SSLNegotiatedCipher[connId]");
```

**SSLNegotiatedCipherStrength**: Returns the negotiated cipher suite strength.This configuration setting returns the strength of the cipher suite negotiated during the SSL handshake.

NOTE: For server components (e.g., TCPServer), this is a per-connection configuration setting accessed by passing the ConnectionId. For example:

```csharp
server.Config("SSLNegotiatedCipherStrength[connId]");
```

**SSLNegotiatedCipherSuite**: Returns the negotiated cipher suite.This configuration setting returns the cipher suite negotiated during the SSL handshake represented as a single string.

NOTE: For server components (e.g., TCPServer), this is a per-connection configuration setting accessed by passing the ConnectionId. For example:

```csharp
server.Config("SSLNegotiatedCipherSuite[connId]");
```

**SSLNegotiatedKeyExchange**: Returns the negotiated key exchange algorithm.This configuration setting returns the key exchange algorithm negotiated during the SSL handshake.

NOTE: For server components (e.g., TCPServer), this is a per-connection configuration setting accessed by passing the ConnectionId. For example:

```csharp
server.Config("SSLNegotiatedKeyExchange[connId]");
```

**SSLNegotiatedKeyExchangeStrength**: Returns the negotiated key exchange algorithm strength.This configuration setting returns the strength of the key exchange algorithm negotiated during the SSL handshake.

NOTE: For server components (e.g., TCPServer), this is a per-connection configuration setting accessed by passing the ConnectionId. For example:

```csharp
server.Config("SSLNegotiatedKeyExchangeStrength[connId]");
```

**SSLNegotiatedVersion**: Returns the negotiated protocol version.This configuration setting returns the protocol version negotiated during the SSL handshake.

NOTE: For server components (e.g., TCPServer), this is a per-connection configuration setting accessed by passing the ConnectionId. For example:

```csharp
server.Config("SSLNegotiatedVersion[connId]");
```

**SSLSecurityFlags**: Flags that control certificate verification.The following flags are defined (specified in hexadecimal notation). They can be ORed together to exclude multiple conditions:

|  |  |
| --- | --- |
| 0x00000001 | Ignore time validity status of certificate. |
| 0x00000002 | Ignore time validity status of CTL. |
| 0x00000004 | Ignore non-nested certificate times. |
| 0x00000010 | Allow unknown certificate authority. |
| 0x00000020 | Ignore wrong certificate usage. |
| 0x00000100 | Ignore unknown certificate revocation status. |
| 0x00000200 | Ignore unknown CTL signer revocation status. |
| 0x00000400 | Ignore unknown certificate authority revocation status. |
| 0x00000800 | Ignore unknown root revocation status. |
| 0x00008000 | Allow test root certificate. |
| 0x00004000 | Trust test root certificate. |
| 0x80000000 | Ignore non-matching CN (certificate CN non-matching server name). |

This functionality is currently not available in Java or when the provider is OpenSSL.

**SSLServerCACerts**: A newline separated list of CA certificates to use during SSL server certificate validation.This configuration setting is only used by client components (e.g., TCPClient) see [SSLClientCACerts](#SSLClientCACerts) for server components (e.g., TCPServer). This configuration setting can be used to optionally specify one or more CA certificates to be used when connecting to the server and verifying the server certificate. When verifying the server's certificate, the certificates trusted by the system will be used as part of the verification process. If the server's CA certificates are not installed to the trusted system store, they may be specified here so they are included when performing the verification process. This configuration setting should be set only if the server's CA certificates are not already trusted on the system and cannot be installed to the trusted system store.

The value of this configuration setting is a newline-separated (CR/LF) list of certificates. For instance:

```text
-----BEGIN CERTIFICATE-----
MIIEKzCCAxOgAwIBAgIRANTET4LIkxdH6P+CFIiHvTowDQYJKoZIhvcNAQELBQAw
... Intermediate Cert...
eWHV5OW1K53o/atv59sOiW5K3crjFhsBOd5Q+cJJnU+SWinPKtANXMht+EDvYY2w
F0I1XhM+pKj7FjDr+XNj
-----END CERTIFICATE-----
\r \n
-----BEGIN CERTIFICATE-----
MIIEFjCCAv6gAwIBAgIQetu1SMxpnENAnnOz1P+PtTANBgkqhkiG9w0BAQUFADBp
... Root Cert...
d8q23djXZbVYiIfE9ebr4g3152BlVCHZ2GyPdjhIuLeH21VbT/dyEHHA
-----END CERTIFICATE-----
```

**TLS12SignatureAlgorithms**: Defines the allowed TLS 1.2 signature algorithms when SSLProvider is set to Internal.This configuration setting specifies the allowed server certificate signature algorithms when SSLProvider is set to *Internal* and [SSLEnabledProtocols](#SSLEnabledProtocols) is set to allow TLS 1.2.

When specified the component will verify that the server certificate signature algorithm is among the values specified in this configuration setting. If the server certificate signature algorithm is unsupported, the component throws an exception.

The format of this value is a comma-separated list of hash-signature combinations. For instance:

```csharp
component.SSLProvider = TCPClientSSLProviders.sslpInternal;
component.Config("SSLEnabledProtocols=3072"); //TLS 1.2
component.Config("TLS12SignatureAlgorithms=sha256-rsa,sha256-dsa,sha1-rsa,sha1-dsa");
```

 The default value for this configuration setting is *sha512-ecdsa,sha512-rsa,sha512-dsa,sha384-ecdsa,sha384-rsa,sha384-dsa,sha256-ecdsa,sha256-rsa,sha256-dsa,sha224-ecdsa,sha224-rsa,sha224-dsa,sha1-ecdsa,sha1-rsa,sha1-dsa*.

To not restrict the server's certificate signature algorithm, specify an empty string as the value for this configuration setting, which will cause the signature_algorithms TLS 1.2 extension to not be sent.

**TLS12SupportedGroups**: The supported groups for ECC.This configuration setting specifies a comma-separated list of named groups used in TLS 1.2 for ECC.

The default value is *ecdhe_secp256r1,ecdhe_secp384r1,ecdhe_secp521r1*.

When using TLS 1.2 and SSLProvider is set to *Internal*, the values refer to the supported groups for ECC. The following values are supported:

- "ecdhe_secp256r1" (default)
- "ecdhe_secp384r1" (default)
- "ecdhe_secp521r1" (default)

**TLS13KeyShareGroups**: The groups for which to pregenerate key shares.This configuration setting specifies a comma-separated list of named groups used in TLS 1.3 for key exchange. The groups specified here will have key share data pregenerated locally before establishing a connection. This can prevent an additional roundtrip during the handshake if the group is supported by the server.

The default value is set to balance common supported groups and the computational resources required to generate key shares. As a result, only some groups are included by default in this configuration setting.

NOTE: All supported groups can always be used during the handshake even if not listed here, but if a group is used that is not present in this list, it will incur an additional roundtrip and time to generate the key share for that group.

In most cases, this configuration setting does not need to be modified. This should be modified only if there is a specific reason to do so.

The default value is *ecdhe_x25519,ecdhe_secp256r1,ecdhe_secp384r1,ffdhe_2048,ffdhe_3072*

The values are ordered from most preferred to least preferred. The following values are supported:

- "ecdhe_x25519" (default)
- "ecdhe_x448"
- "ecdhe_secp256r1" (default)
- "ecdhe_secp384r1" (default)
- "ecdhe_secp521r1"
- "ffdhe_2048" (default)
- "ffdhe_3072" (default)
- "ffdhe_4096"
- "ffdhe_6144"
- "ffdhe_8192"

**TLS13SignatureAlgorithms**: The allowed certificate signature algorithms.This configuration setting holds a comma-separated list of allowed signature algorithms. Possible values include the following:

- "ed25519" (default)
- "ed448" (default)
- "ecdsa_secp256r1_sha256" (default)
- "ecdsa_secp384r1_sha384" (default)
- "ecdsa_secp521r1_sha512" (default)
- "rsa_pkcs1_sha256" (default)
- "rsa_pkcs1_sha384" (default)
- "rsa_pkcs1_sha512" (default)
- "rsa_pss_sha256" (default)
- "rsa_pss_sha384" (default)
- "rsa_pss_sha512" (default)

 The default value is *rsa_pss_sha256,rsa_pss_sha384,rsa_pss_sha512,rsa_pkcs1_sha256,rsa_pkcs1_sha384,rsa_pkcs1_sha512,ecdsa_secp256r1_sha256,ecdsa_secp384r1_sha384,ecdsa_secp521r1_sha512,ed25519,ed448*. This configuration setting is applicable only when [SSLEnabledProtocols](#SSLEnabledProtocols) includes TLS 1.3.

**TLS13SupportedGroups**: The supported groups for (EC)DHE key exchange.This configuration setting specifies a comma-separated list of named groups used in TLS 1.3 for key exchange. This configuration setting should be modified only if there is a specific reason to do so.

The default value is *ecdhe_x25519,ecdhe_x448,ecdhe_secp256r1,ecdhe_secp384r1,ecdhe_secp521r1,ffdhe_2048,ffdhe_3072,ffdhe_4096,ffdhe_6144,ffdhe_8192,mlkem_512,mlkem_768,mlkem_1024,x25519_mlkem_768,secp256r1_mlkem_768*

The values are ordered from most preferred to least preferred. The following values are supported:

- "ecdhe_x25519" (default)
- "ecdhe_x448" (default)
- "ecdhe_secp256r1" (default)
- "ecdhe_secp384r1" (default)
- "ecdhe_secp521r1" (default)
- "ffdhe_2048" (default)
- "ffdhe_3072" (default)
- "ffdhe_4096" (default)
- "ffdhe_6144" (default)
- "ffdhe_8192" (default)
- "mlkem_512" (default)
- "mlkem_768" (default)
- "mlkem_1024" (default)
- "x25519_mlkem_768" (default)
- "secp256r1_mlkem_768" (default)

Post-quantum algorithms (*mlkem_512,mlkem_768,mlkem_1024,x25519_mlkem_768,secp256r1_mlkem_768*) in our components rely on the operating system's underlying cryptographic primitives. The following platforms are currently supported:

-  Windows Server 2025
-  Windows 11 24H2
-  Windows 11 25H2

### UDP Config Settings

**CaptureIPPacketInfo**: Used to capture the packet information.If this is set to True, the component will capture the IP packet information.

The default value for this setting is False.

NOTE: This configuration setting is available only in Windows.

**DelayHostResolution**: Whether the hostname is resolved when RemoteHost is set.This configuration setting specifies whether a hostname is resolved immediately when RemoteHost is set. If *true* the component will resolve the hostname and the IP address will be present in the RemoteHost property. If *false*, the hostname is not resolved until needed by the component when a method to connect or send data is called. If desired, ResolveRemoteHost may be called to manually resolve the value in RemoteHost at any time.

The default value is *false* for the default library and *true* for the async library.

**DestinationAddress**: Used to get the destination address from the packet information.If [CaptureIPPacketInfo](#CaptureIPPacketInfo) is set to True, then this will be populated with the packet's destination address when a packet is received. This information will be accessible in the DataIn event.

NOTE: This configuration setting is available only in Windows.

**DontFragment**: Used to set the Don't Fragment flag of outgoing packets.When set to True, packets sent by the component will have the Don't Fragment flag set. The default value is False.

**LocalHost**: The name of the local host through which connections are initiated or accepted. The [LocalHost](#localhost-property-coap-component) setting contains the name of the local host as obtained by the *gethostname()* system call, or if the user has assigned an IP address, the value of that address.

In multihomed hosts (machines with more than one IP interface), setting LocalHost to the value of an interface will make the component initiate connections (or accept in the case of server components) only through that interface.

If the component is connected, the [LocalHost](#localhost-property-coap-component) setting shows the IP address of the interface through which the connection is made in internet dotted format (aaa.bbb.ccc.ddd). In most cases, this is the address of the local host, except for multihomed hosts (machines with more than one IP interface).

**LocalPort**: The port in the local host where the component binds. This configuration setting must be set before a connection is attempted. It instructs the component to bind to a specific port (or communication endpoint) in the local machine.

Setting this to 0 (default) enables the system to choose a port at random. The chosen port will be shown by [LocalPort](#localport-property-coap-component) after the connection is established.

[LocalPort](#localport-property-coap-component) cannot be changed once a connection is made. Any attempt to set this when a connection is active will generate an error.

This configuration setting is useful when trying to connect to services that require a trusted port on the client side. An example is the remote shell (rsh) service in UNIX systems.

**MaxPacketSize**: The maximum length of the packets that can be received.This configuration setting specifies the maximum size of the datagrams that the component will accept without truncation.

**QOSDSCPValue**: Used to specify an arbitrary QOS/DSCP setting (optional).[UseConnection](#UseConnection) must be True to use this configuration setting. This option allows you to specify an arbitrary DSCP value between 0 and 63. The default is 0. When set to the default value, the component will not set a DSCP value.

NOTE: This configuration setting uses the qWAVE API and is available only on Windows 7, Windows Server 2008 R2, and later.

**QOSTrafficType**: Used to specify QOS/DSCP settings (optional).[UseConnection](#UseConnection) must be True to use this setting. You may specify either the text or integer values: BestEffort (0), Background (1), ExcellentEffort (2), AudioVideo (3), Voice (4), and Control (5).

NOTE: This configuration setting uses the qWAVE API and is available only on Windows Vista and Windows Server 2008 or above.

NOTE: QOSTrafficType must be set before setting Active to True.

**ShareLocalPort**: If set to True, allows more than one instance of the component to be active on the same local port.This option must be set before the component is activated through the Active property or it will have no effect.

The default value for this setting is False.

**UseConnection**: Determines whether to use a connected socket.[UseConnection](#UseConnection) specifies whether or not the component should use a connected socket. The connection is defined as an association in between the local address/port and the remote address/port. As such, this is not a connection in the traditional Transmission Control Protocol (TCP) sense. It means only that the component will send and receive data to and from the specified destination.

The default value for this setting is False.

**UseIPv6**: Whether or not to use IPv6.By default, the component expects an IPv4 address for local and remote host properties, and it will create an IPv4 socket. To use IPv6 instead, set this to True.

### Socket Config Settings

**AbsoluteTimeout**: Determines whether timeouts are inactivity timeouts or absolute timeouts.If [AbsoluteTimeout](#AbsoluteTimeout) is set to True, any method that does not complete within [Timeout](#timeout-property-coap-component) seconds will be aborted. By default, *AbsoluteTimeout* is False, and the timeout is an inactivity timeout.

NOTE: This option is not valid for User Datagram Protocol (UDP) ports.

**FirewallData**: Used to send extra data to the firewall.When the firewall is a tunneling proxy, use this property to send custom (additional) headers to the firewall (e.g., headers for custom authentication schemes).

**InBufferSize**: The size in bytes of the incoming queue of the socket.This is the size of an internal queue in the Transmission Control Protocol (TCP)/IP stack. You can increase or decrease its size depending on the amount of data that you will be receiving. In some cases, increasing the value of the *InBufferSize* setting can provide significant improvements in performance.

Some TCP/IP implementations do not support variable buffer sizes. If that is the case, when the component is activated the *InBufferSize* reverts to its defined size. The same happens if you attempt to make it too large or too small.

**OutBufferSize**: The size in bytes of the outgoing queue of the socket.This is the size of an internal queue in the TCP/IP stack. You can increase or decrease its size depending on the amount of data that you will be sending. In some cases, increasing the value of the *OutBufferSize* setting can provide significant improvements in performance.

Some TCP/IP implementations do not support variable buffer sizes. If that is the case, when the component is activated the *OutBufferSize* reverts to its defined size. The same happens if you attempt to make it too large or too small.

### Base Config Settings

**BuildInfo**: Information about the product's build.When queried, this setting will return a string containing information about the product's build.

**GUIAvailable**: Whether or not a message loop is available for processing events.In a GUI-based application, long-running blocking operations may cause the application to stop responding to input until the operation returns. The component will attempt to discover whether or not the application has a message loop and, if one is discovered, it will process events in that message loop during any such blocking operation.

In some non-GUI applications, an invalid message loop may be discovered that will result in errant behavior. In these cases, setting [GUIAvailable](#GUIAvailable) to *false* will ensure that the component does not attempt to process external events.

**LicenseInfo**: Information about the current license.When queried, this setting will return a string containing information about the license this instance of a component is using. It will return the following information:

- Product: The product the license is for.
- Product Key: The key the license was generated from.
- License Source: Where the license was found (e.g., RuntimeLicense, License File).
- License Type: The type of license installed (e.g., Royalty Free, Single Server).
- Last Valid Build: The last valid build number for which the license will work.

**MaskSensitiveData**: Whether sensitive data is masked in log messages.In certain circumstances it may be beneficial to mask sensitive data, like passwords, in log messages. Set this to *true* to mask sensitive data. The default is *true*.

**UseFIPSCompliantAPI**: Tells the component whether or not to use FIPS certified APIs.When set to *true*, the component will utilize the underlying operating system's certified APIs. Java editions, regardless of OS, utilize Bouncy Castle Federal Information Processing Standards (FIPS), while all other Windows editions make use of Microsoft security libraries.

FIPS mode can be enabled by setting the *UseFIPSCompliantAPI* configuration setting to *true*. This is a static setting that applies to all instances of all components of the toolkit within the process. It is recommended to enable or disable this setting once before the component has been used to establish a connection. Enabling FIPS while an instance of the component is active and connected may result in unexpected behavior.

For more details, please see the [FIPS 140-2 Compliance](https://www.nsoftware.com/kb/articles/fips.rst) article.

NOTE: This setting is applicable only on Windows.

NOTE: Enabling FIPS compliance requires a special license; please contact [sales@nsoftware.com](mailto:sales@nsoftware.com) for details.

**UseInternalSecurityAPI**: Whether or not to use the system security libraries or an internal implementation. When set to *false*, the component will use the system security libraries by default to perform cryptographic functions where applicable. In this case, calls to unmanaged code will be made. In certain environments, this is not desirable. To use a completely managed security implementation, set this setting to *true*.

Setting this configuration setting to *true* tells the component to use the internal implementation instead of using the system security libraries.

 On Windows, this setting is set to *false* by default. On Linux/macOS, this setting is set to *true* by default.

NOTE: This setting is static. The value set is applicable to all components used in the application.

When this value is set, the product's system dynamic link library (DLL) is no longer required as a reference, as all unmanaged code is stored in that file.

# Trappable Errors ([CoAP](#coap-component) Component)

### CoAP Errors

|  |  |
| --- | --- |
| 700 | Invalid or malformed URI. |
| 701 | Invalid or malformed option. |
| 702 | Invalid block. |
| 703 | Malformed message. |
| 704 | Message transmission timed out. |
| 705 | Message rejected by remote host. |
| 706 | Invalid/unexpected request Id. |
| 707 | Invalid response code. |
| 708 | "Reset" message received from remote host. |
| 709 | Error response received from server. Refer to the error message for more information. |
| 710 | Observation not supported for the requested URI. |
| 711 | Request canceled. |
| 712 | The requested operation cannot be performed in the current mode. |
