TCPServer Component

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The TCPServer Component is a generic Transmission Control Protocol (TCP) server component based on an asynchronous, event-driven architecture. It is designed to balance the load between connections for a fast, powerful server.

Syntax

TipwTCPServer

Remarks

The TCPServer Component supports both plaintext and Secure Sockets Layer/Transport Layer Security (SSL/TLS) connections. When connecting over SSL/TLS the SSLServerAuthentication event allows you to check the server identity and other security attributes. The SSLStatus event provides information about the SSL handshake. Additional SSL related settings are also supported via the Config method. The SSLCert properties are used to select a certificate for the server. Note: A valid certificate MUST be selected before the server can function.

TCPServer is the server complement of TCPClient, which is used to create client applications. They share a common design philosophy and interface. We expect you will find TCPServer as easy to use as TCPClient.

By default, each instance of TCPServer can handle up to 1,000 simultaneous incoming connections. This number may be increased up to 100,000 or decreased to a lower value by using the MaxConnections configuration setting.

The connections are identified by a ConnectionId, an Id generated by the component to identify each connection. This Id is unique to each connection. TCPServer's events also have ConnectionId as a parameter to identify the connection they relate to.

Our main goal in designing TCPServer was to make it easy to use without sacrificing performance. The component has a minimum of properties, and six events: ConnectionRequest, Connected, DataIn, Disconnected, ReadyToSend, and Error.

TCPServer can start to listen on a port by setting the Listening property to True. When a remote host asks for a connection, the ConnectionRequest event is fired. At that point, the connection can either be accepted or rejected. If the connection is accepted, a ConnectionId is assigned, and communication can start. From this point on, the operation is very similar to TCPClient. Data are sent by assigning the data string to the DataToSend property. The address and port of the incoming connection can be found by querying the RemoteHost and RemotePort properties.

Note: Server components are designed to process events as they occur. To ensure that events are processed in a timely manner, DoEvents should be called in a loop after the server is started.

Property List

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

Method List

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

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.

Config Settings

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

ConnectionBacklog Property (TCPServer Component)

This property includes the maximum number of pending connections maintained by the Transmission Control Protocol (TCP)/IP subsystem.

Syntax

property ConnectionBacklog: Integer read get_ConnectionBacklog write set_ConnectionBacklog;

Default Value

5

Remarks

This property contains the maximum number of pending connections maintained by the TCP/IP subsystem. This value reflects the SOMAXCONN option for the main listening socket. The default value for most systems is 5. You may set this property to a larger value if the server is expected to receive a large number of connections, and queuing them is desirable.

This property is not available at design time.

Connections Property (TCPServer Component)

This property includes a collection of currently connected clients.

Syntax

property Connections: TipwConnectionList read get_Connections;

Remarks

This property contains a collection of currently connected clients. All of the connections may be managed using this property. Each connection is described by the different fields of the Connection type.

This collection is a hash-table type of collection, in which the Connection Id string is used as the key to the desired connection. You may acquire the key for a given connection through the Connected event.

Example (Broadcasting Data) For i = 0 to Control.ConnectionCount Control.DataToSend(Control.ConnectionId(i)) = "Broadcast Data" Next i

This property is read-only.

DefaultEOL Property (TCPServer Component)

This property includes a default end-of-line (EOL) value to be used by incoming connections.

Syntax

property DefaultEOL: String read get_DefaultEOL write set_DefaultEOL;
property DefaultEOLB: TBytes read get_DefaultEOLB write set_DefaultEOLB;

Default Value

''

Remarks

This property contains a default end-of-line (EOL) value to be used by incoming connections. Once the component accepts and establishes an inbound connection, it will set that connection's EOL to the value in this property. By default, this value is empty (""), meaning that data will be fired as it is received.

DefaultIdleTimeout Property (TCPServer Component)

This property includes the default idle timeout for inactive clients.

Syntax

property DefaultIdleTimeout: Integer read get_DefaultIdleTimeout write set_DefaultIdleTimeout;

Default Value

0

Remarks

This property specifies the idle timeout (in seconds) for clients. When set to a positive value, the component will disconnect idle clients after the specified timeout.

This applies only to clients that have not sent or received data within DefaultIdleTimeout seconds.

If set to 0 (default), no idle timeout is applied.

Note: DoEvents must be called for the component to check existing connections.

DefaultMaxLineLength Property (TCPServer Component)

The property includes the default maximum line length value for inbound connections.

Syntax

property DefaultMaxLineLength: Integer read get_DefaultMaxLineLength write set_DefaultMaxLineLength;

Default Value

2048

Remarks

This property controls the default size of an internal buffer that holds received data while waiting for an end-of-line (EOL) string.

The minimum value for this property is 256 bytes. The default value is 2048 bytes.

DefaultSingleLineMode Property (TCPServer Component)

This property tells the component whether or not to treat new connections as line oriented.

Syntax

property DefaultSingleLineMode: Boolean read get_DefaultSingleLineMode write set_DefaultSingleLineMode;

Default Value

false

Remarks

This property instructs the component whether or not to treat newly established connections as line-oriented protocols. If this value is True, newly accepted connections will read the incoming data stream as lines separated by a carriage return line feed (CRLF), carriage return (CR), or line feed (LF) and will ignore the end of lines (EOLs).

DefaultTimeout Property (TCPServer Component)

This property includes an initial timeout value to be used by incoming connections.

Syntax

property DefaultTimeout: Integer read get_DefaultTimeout write set_DefaultTimeout;

Default Value

0

Remarks

This property is used by the component to set the operational timeout value of all inbound connections once they are established.

By default, the timeout is 0, meaning that all inbound connections will behave asynchronously.

KeepAlive Property (TCPServer Component)

When True, KEEPALIVE packets are enabled (for long connections).

Syntax

property KeepAlive: Boolean read get_KeepAlive write set_KeepAlive;

Default Value

false

Remarks

This property enables the SO_KEEPALIVE option on the incoming connections. This option prevents long connections from timing out in case of inactivity.

Note: System Transmission Control Protocol (TCP)/IP stack implementations are not required to support SO_KEEPALIVE.

This property is shared among incoming connections. When the property is set, the corresponding value is set for incoming connections as they are accepted. Existing connections are not modified.

Linger Property (TCPServer Component)

When set to True, connections are terminated gracefully.

Syntax

property Linger: Boolean read get_Linger write set_Linger;

Default Value

true

Remarks

This property controls how a connection is closed. The default is True. In this case, the connection is closed only after all the data are sent. Setting it to False forces an abrupt (hard) disconnection. Any data that were in the sending queue may be lost.

The default behavior (which is also the default mode for stream sockets) might result in an indefinite delay in closing the connection. Although the component returns control immediately, the system might indefinitely hold system resources until all pending data are sent (even after your application closes). This means that valuable system resources might be wasted.

Setting this property to False forces an immediate disconnection. If you know that the other side has received all the data you have sent (e.g., by a client acknowledgment), then setting this property to False might be the appropriate course of action.

This property is shared among incoming connections. When the property is set, the corresponding value is set for incoming connections as they are accepted. Existing connections are not modified.

Listening Property (TCPServer Component)

If set to True, the component accepts incoming connections on LocalPort.

Syntax

property Listening: Boolean read get_Listening write set_Listening;

Default Value

false

Remarks

This property indicates whether the component is listening for connections on the port specified by the LocalPort property.

Note: Use the StartListening and StopListening methods to control whether the component is listening.

This property is not available at design time.

LocalHost Property (TCPServer Component)

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

Syntax

property LocalHost: String read get_LocalHost write set_LocalHost;

Default Value

''

Remarks

The LocalHost 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 multi-homed 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 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 multi-homed 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 (TCPServer Component)

This property includes the Transmission Control Protocol (TCP) port in the local host where the component listens.

Syntax

property LocalPort: Integer read get_LocalPort write set_LocalPort;

Default Value

0

Remarks

This property must be set before the component can start listening. If its value is 0, then the TCP/IP subsystem picks a port number at random. The port number can be found by checking the value of this property after the component is listening (i.e., after successfully assigning True to the Listening property).

The service port is not shared among servers so two components cannot be listening on the same port at the same time.

SSLAuthenticateClients Property (TCPServer Component)

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

Syntax

property SSLAuthenticateClients: Boolean read get_SSLAuthenticateClients write set_SSLAuthenticateClients;

Default Value

false

Remarks

This property is used in conjunction with the SSLClientAuthentication event. Please refer to the documentation of the SSLClientAuthentication event for details.

SSLCertEncoded Property (TCPServer Component)

This is the certificate (PEM/Base64 encoded).

Syntax

property SSLCertEncoded: String read get_SSLCertEncoded write set_SSLCertEncoded;
property SSLCertEncodedB: TBytes read get_SSLCertEncodedB write set_SSLCertEncodedB;

Default Value

''

Remarks

This is the certificate (PEM/Base64 encoded). This property is used to assign a specific certificate. The Store and Subject properties also may be used to specify a certificate.

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

This property is not available at design time.

SSLCertStore Property (TCPServer Component)

This is the name of the certificate store for the client certificate.

Syntax

property SSLCertStore: String read get_SSLCertStore write set_SSLCertStore;
property SSLCertStoreB: TBytes read get_SSLCertStoreB write set_SSLCertStoreB;

Default Value

'MY'

Remarks

This is the name of the certificate store for the client certificate.

The StoreType property denotes the type of the certificate store specified by Store. If the store is password protected, specify the password in StorePassword.

Store is used in conjunction with the Subject property to specify client certificates. If Store has a value, and Subject or Encoded is set, a search for a certificate is initiated. Please see the Subject property for details.

Designations of certificate stores are platform dependent.

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

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

SSLCertStorePassword Property (TCPServer Component)

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

Syntax

property SSLCertStorePassword: String read get_SSLCertStorePassword write set_SSLCertStorePassword;

Default Value

''

Remarks

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

SSLCertStoreType Property (TCPServer Component)

This is the type of certificate store for this certificate.

Syntax

property SSLCertStoreType: TipwCertStoreTypes read get_SSLCertStoreType write set_SSLCertStoreType;

TipwCertStoreTypes = (
  cstUser,
  cstMachine,
  cstPFXFile,
  cstPFXBlob,
  cstJKSFile,
  cstJKSBlob,
  cstPEMKeyFile,
  cstPEMKeyBlob,
  cstPublicKeyFile,
  cstPublicKeyBlob,
  cstSSHPublicKeyBlob,
  cstP7BFile,
  cstP7BBlob,
  cstSSHPublicKeyFile,
  cstPPKFile,
  cstPPKBlob,
  cstXMLFile,
  cstXMLBlob,
  cstJWKFile,
  cstJWKBlob,
  cstSecurityKey,
  cstBCFKSFile,
  cstBCFKSBlob,
  cstPKCS11,
  cstAuto
);

Default Value

cstUser

Remarks

This is 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 property can take one of the following values:

SSLCertSubject Property (TCPServer Component)

This is the subject of the certificate used for client authentication.

Syntax

property SSLCertSubject: String read get_SSLCertSubject write set_SSLCertSubject;

Default Value

''

Remarks

This is the subject of the certificate used for client authentication.

This property must be set after all other certificate properties are set. When this property is set, a search is performed in the current certificate store to locate a certificate with a matching subject.

If a matching certificate is found, the property is set to the full subject of the matching certificate.

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=support@nsoftware.com". Common fields and their meanings are as follows:

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

SSLEnabled Property (TCPServer Component)

Whether TLS/SSL is enabled.

Syntax

property SSLEnabled: Boolean read get_SSLEnabled write set_SSLEnabled;

Default Value

false

Remarks

This setting 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.

SSLProvider Property (TCPServer Component)

This specifies the SSL/TLS implementation to use.

Syntax

property SSLProvider: TipwTSSLProviders read get_SSLProvider write set_SSLProvider;

TipwTSSLProviders = (
  sslpAutomatic,
  sslpPlatform,
  sslpInternal
);

Default Value

sslpAutomatic

Remarks

This property specifies the SSL/TLS implementation to use. In most cases the default value of 0 (Automatic) is recommended and should not be changed. When set to 0 (Automatic) the component will select whether to use the platform implementation or the internal implementation depending on the operating system as well as the TLS version being used.

Possible values are:

In most cases using the default value (Automatic) is recommended. The component will select a provider depending on the current platform.

When Automatic is selected, on Windows the component will use the platform implementation. On Linux/macOS the component will use the internal implementation. When TLS 1.3 is enabled via SSLEnabledProtocols the internal implementation is used on all platforms.

SSLStartMode Property (TCPServer Component)

Determines how the component starts the SSL negotiation.

Syntax

property SSLStartMode: TipwTSSLStartModes read get_SSLStartMode write set_SSLStartMode;

TipwTSSLStartModes = (
  sslAutomatic,
  sslImplicit,
  sslExplicit,
  sslNone
);

Default Value

sslNone

Remarks

The SSLStartMode property may have one of the following values:

ChangeRecordLength Method (TCPServer Component)

This method changes the length of received data records.

Syntax

procedure ChangeRecordLength(ConnectionId: Integer; RecordLength: Integer);

Remarks

This method defines the length of data records to be received (in bytes) for the specified ConnectionId.

If RecordLength is set to a positive value, the component will accumulate data until RecordLength bytes of data are received and only then will fire the DataIn event with data of the specified length RecordLength. This allows data to be received as records of known length. This method can be called at any time to change the record length, including within the DataIn event.

A value of 0 (default) means this functionality is not used.

Config Method (TCPServer Component)

Sets or retrieves a configuration setting.

Syntax

function Config(ConfigurationString: String): String;

Remarks

Config is a generic method available in every component. It is used to set and retrieve configuration settings 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, you must call Config("PROPERTY"). The value will be returned as a string.

Disconnect Method (TCPServer Component)

This method disconnects the specified client.

Syntax

procedure Disconnect(ConnectionId: Integer);

Remarks

Calling this method will disconnect the client specified by the ConnectionId parameter.

DoEvents Method (TCPServer Component)

Processes events from the internal message queue.

Syntax

procedure DoEvents();

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.

Interrupt Method (TCPServer Component)

This method interrupts a synchronous send to the remote host.

Syntax

procedure Interrupt(ConnectionId: Integer);

Remarks

This property is called using the Connection Id if you wish to interrupt a connection and stop a file from uploading without disconnecting the client connected to the component. If you use SendFile to upload a file, the component will run synchronously on that Connection Id until it is completed.

PauseData Method (TCPServer Component)

This method pauses data reception.

Syntax

procedure PauseData(ConnectionId: Integer);

Remarks

This method pauses data reception for the connection identified by ConnectionId when called. While data reception is paused, the DataIn event will not fire for the specified connection. Call ProcessData to reenable data reception.

ProcessData Method (TCPServer Component)

This method reenables data reception after a call to PauseData .

Syntax

procedure ProcessData(ConnectionId: Integer);

Remarks

This method reenables data reception for the connection identified by ConnectionId after a previous call to PauseData. When PauseData is called, the DataIn event will not fire for the specified connection. To reenable data reception and allow DataIn to fire, call this method.

Note: This method is used only after previously calling PauseData. It does not need to be called to process incoming data by default.

Reset Method (TCPServer Component)

Reset the component.

Syntax

procedure Reset();

Remarks

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

Send Method (TCPServer Component)

This method sends binary data to the specified client.

Syntax

procedure Send(ConnectionId: Integer; Text: TBytes);

Remarks

This method sends binary data to the client identified by ConnectionId. To send text, use the SendText method instead.

When Timeout is set to 0, the component will behave asynchronously. If you are sending data to the remote host faster than it can process it, or faster than the network's bandwidth allows, the outgoing queue might fill up. When this happens, the operation raises the exception with errorcode 10035 and message '[10035] Operation would block' (WSAEWOULDBLOCK). You can handle this exception, and then try to send the data again. . The BytesSent property shows how many bytes were sent (if any). If 0 bytes were sent, then you can wait for the ReadyToSend event before attempting to send data again.

Note: The ReadyToSend event is not fired when part of the data is sent successfully.

SendBytes Method (TCPServer Component)

This method sends binary data to the specified client.

Syntax

procedure SendBytes(ConnectionId: Integer; Data: TBytes);

Remarks

This method sends binary data to the client identified by ConnectionId. To send text, use the SendText method instead.

When Timeout is set to 0, the component will behave asynchronously. If you are sending data to the remote host faster than it can process it, or faster than the network's bandwidth allows, the outgoing queue might fill up. When this happens, the operation raises the exception with errorcode 10035 and message '[10035] Operation would block' (WSAEWOULDBLOCK). You can handle this exception, and then try to send the data again. . The BytesSent property shows how many bytes were sent (if any). If 0 bytes were sent, then you can wait for the ReadyToSend event before attempting to send data again.

Note: The ReadyToSend event is not fired when part of the data is sent successfully.

SendFile Method (TCPServer Component)

This method sends the file to the remote host.

Syntax

procedure SendFile(ConnectionId: Integer; FileName: String);

Remarks

This method sends the file to the client specified by the ConnectionId.

SendLine Method (TCPServer Component)

This method sends a string followed by a new line.

Syntax

procedure SendLine(ConnectionId: Integer; Text: String);

Remarks

This method is used to send data with line-oriented protocols. The line is followed by CRLF ('#13#10') .

Please refer to the GetLine method and SingleLineMode property for more information.

SendText Method (TCPServer Component)

This method sends text to the specified client.

Syntax

procedure SendText(ConnectionId: Integer; Text: String);

Remarks

This method sends text to the client identified by ConnectionId. To send binary data, use the SendBytes method instead.

When Timeout is set to 0, the component will behave asynchronously. If you are sending data to the remote host faster than it can process it, or faster than the network's bandwidth allows, the outgoing queue might fill up. When this happens, the operation raises the exception with errorcode 10035 and message '[10035] Operation would block' (WSAEWOULDBLOCK). You can handle this exception, and then try to send the data again. . The BytesSent property shows how many bytes were sent (if any). If 0 bytes were sent, then you can wait for the ReadyToSend event before attempting to send data again.

Note: The ReadyToSend event is not fired when part of the data is sent successfully.

Shutdown Method (TCPServer Component)

This method shuts down the server.

Syntax

procedure Shutdown();

Remarks

This method shuts down the server. Calling this method is equivalent to calling StopListening and then breaking every client connection by calling Disconnect.

StartListening Method (TCPServer Component)

This method starts listening for incoming connections.

Syntax

procedure StartListening();

Remarks

This method begins listening for incoming connections on the port specified by LocalPort. Once listening, events will fire as new clients connect and data are transferred.

To stop listening for new connections, call StopListening. To stop listening for new connections and to disconnect all existing clients, call Shutdown.

StartSSL Method (TCPServer Component)

This method starts the Secure Sockets Layer (SSL) negotiation on a connection.

Syntax

procedure StartSSL(ConnectionId: Integer);

Remarks

This method is used to start the SSL negotiation on a plaintext connection. Please refer to the SSLStartMode property for more information.

Note: The Connected event will fire again after the SSL negotiation is complete.

StopListening Method (TCPServer Component)

This method stops listening for new connections.

Syntax

procedure StopListening();

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.

Connected Event (TCPServer Component)

This event is fired immediately after a connection completes (or fails).

Syntax

type TConnectedEvent = procedure (
  Sender: TObject;
  ConnectionId: Integer;
  StatusCode: Integer;
  const Description: String
) of Object;

property OnConnected: TConnectedEvent read FOnConnected write FOnConnected;

Remarks

If the connection is made normally, StatusCode is 0, and Description is 'OK'.

If the connection fails, StatusCode has the error code returned by the system. Description contains a description of this code. The value of StatusCode is equal to the value of the system error.

Please refer to the Error Codes section for more information.

ConnectionRequest Event (TCPServer Component)

This event is fired when a request for connection comes from a remote host.

Syntax

type TConnectionRequestEvent = procedure (
  Sender: TObject;
  const Address: String;
  Port: Integer;
  var Accept: Boolean
) of Object;

property OnConnectionRequest: TConnectionRequestEvent read FOnConnectionRequest write FOnConnectionRequest;

Remarks

This event indicates an incoming connection. The connection is accepted by default. Address and Port will contain information about the remote host requesting the inbound connection. If you want to refuse it, you can set the Accept parameter to False.

DataIn Event (TCPServer Component)

This event is fired when data come in.

Syntax

type TDataInEvent = procedure (
  Sender: TObject;
  ConnectionId: Integer;
  Text: String;
  TextB: TBytes;
  EOL: Boolean
) of Object;

property OnDataIn: TDataInEvent read FOnDataIn write FOnDataIn;

Remarks

Trapping the DataIn event is your only chance to get the data coming from the other end of the connection specified by ConnectionId. The incoming data are provided through the Text parameter.

EOL indicates whether or not the EOL string was found at the end of Text. If the EOL string was found, then EOL is True.

If Text is part of the data portion of length larger than either DefaultMaxLineLength or MaxLineLength with no EOL strings in it, then EOL is False. Please note that this means that one or more DataIn events with EOL set to False can be received during a connection.

If the EOL property is '' (empty string), then EOL can be disregarded (it is always True).

Note: Events are not re-entrant. Performing time-consuming operations within this event will prevent it from firing again in a timely manner and may affect overall performance.

Disconnected Event (TCPServer Component)

This event is fired when a connection is closed.

Syntax

type TDisconnectedEvent = procedure (
  Sender: TObject;
  ConnectionId: Integer;
  StatusCode: Integer;
  const Description: String
) of Object;

property OnDisconnected: TDisconnectedEvent read FOnDisconnected write FOnDisconnected;

Remarks

If the connection is broken normally, StatusCode is 0, and Description is 'OK'.

If the connection is broken for any other reason, StatusCode has the error code returned by the system. Description contains a description of this code. The value of StatusCode is equal to the value of the system error.

Please refer to the Error Codes section for more information.

Error Event (TCPServer Component)

This event fires information about errors during data delivery.

Syntax

type TErrorEvent = procedure (
  Sender: TObject;
  ConnectionId: Integer;
  ErrorCode: Integer;
  const Description: String
) of Object;

property OnError: TErrorEvent read FOnError write FOnError;

Remarks

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

ErrorCode contains an error code and Description contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

ConnectionId indicates the connection for which the error is applicable.

ReadyToSend Event (TCPServer Component)

This event is fired when the component is ready to send data.

Syntax

type TReadyToSendEvent = procedure (
  Sender: TObject;
  ConnectionId: Integer
) of Object;

property OnReadyToSend: TReadyToSendEvent read FOnReadyToSend write FOnReadyToSend;

Remarks

The ReadyToSend event indicates that the underlying Transmission Control Protocol (TCP)/IP subsystem is ready to accept data after a failed DataToSend. This event is also fired immediately after a connection is established.

SSLClientAuthentication Event (TCPServer Component)

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

Syntax

type TSSLClientAuthenticationEvent = procedure (
  Sender: TObject;
  ConnectionId: Integer;
  CertEncoded: String;
  CertEncodedB: TBytes;
  const CertSubject: String;
  const CertIssuer: String;
  const Status: String;
  var Accept: Boolean
) of Object;

property OnSSLClientAuthentication: TSSLClientAuthenticationEvent read FOnSSLClientAuthentication write FOnSSLClientAuthentication;

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").

SSLConnectionRequest Event (TCPServer Component)

This event fires when a Secure Sockets Layer (SSL) connection is requested.

Syntax

type TSSLConnectionRequestEvent = procedure (
  Sender: TObject;
  ConnectionId: Integer;
  const SupportedCipherSuites: String;
  const SupportedSignatureAlgs: String;
  var CertStoreType: Integer;
  var CertStore: String;
  var CertPassword: String;
  var CertSubject: String
) of Object;

property OnSSLConnectionRequest: TSSLConnectionRequestEvent read FOnSSLConnectionRequest write FOnSSLConnectionRequest;

Remarks

This event fires when an SSL connection is requested and SSLProvider is set to Internal. This event provides an opportunity to select an alternative certificate to the connecting client. This event does not fire when SSLProvider is set to Platform.

This event allows the component to be configured to use both RSA and ECDSA certificates depending on the connecting client's capabilities.

ConnectionId is the connection Id of the client requesting the connection.

SupportedCipherSuites is a comma-separated list of cipher suites that the client supports.

SupportedSignatureAlgs is a comma-separated list of certificate signature algorithms that the client supports.

CertStoreType is the store type of the alternate certificate to use for this connection. 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 property can take one of the following values:

CertStore is the store name or location of the alternate certificate to use for this connection.

Designations of certificate stores are platform dependent.

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

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

CertPassword is the password of the certificate store containing the alternate certificate to use for this connection.

CertSubject is the subject of the alternate certificate to use for this connection.

The special value * matches any subject and will select the first certificate in the 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=support@nsoftware.com". Common fields and their meanings are as follows:

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

SSLStatus Event (TCPServer Component)

This event is fired to show the progress of the secure connection.

Syntax

type TSSLStatusEvent = procedure (
  Sender: TObject;
  ConnectionId: Integer;
  const Message: String
) of Object;

property OnSSLStatus: TSSLStatusEvent read FOnSSLStatus write FOnSSLStatus;

Remarks

The event is fired for informational and logging purposes only. It is used to track the progress of the connection.

Connection Type

This is a currently connected client.

Remarks

This type describes the connection of a client that is currently connected to the component. You may use the different fields of this type to manage the connection.

Fields

Constructors

constructor Create();

Config Settings (TCPServer Component)

TCPServer Config Settings

SSL Config Settings

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

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

Base Config Settings

Trappable Errors (TCPServer Component)

TCPServer Errors

SSL Errors

TCP/IP Errors