STOMP Class

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A simple but powerful STOMP client implementation.

Syntax

ipworksiot.Stomp

Remarks

The STOMP class provides an easy-to-use STOMP client implementation that supports STOMP versions 1.1 and 1.2. The class supports both plaintext and TLS-enabled connections over TCP.

Connecting

Connecting to a STOMP server is easy; in the simplest case just call the ConnectTo method, passing the server's hostname and port number.

When connecting to a STOMP server, the class sends information from the following properties, if populated:

• IncomingHeartbeat
• OutgoingHeartbeat
• User
• Password

In addition to the above properties, the following configuration settings can be set before connecting (though in most cases this is not necessary):

• SupportedVersions: Controls which STOMP versions the class advertises support for.
• VirtualHost: Controls the virtual host to connect to. If left empty (default), the value from RemoteHost is used.

Subscriptions & Receiving Messages

When Subscribe is called, it will return a subscription Id. To unsubscribe, pass this subscription Id to the Unsubscribe method.

After subscribing to a message destination, any messages received will cause the MessageIn event to fire.

Basic Subscriptions Example stomp1.OnMessageIn += (s, e) => { Console.WriteLine("Received message from destination '" + e.Destination + "':"); Console.WriteLine(e.Data); }; string subId = stomp1.Subscribe("test/a/b", false); // Some time later... stomp1.Unsubscribe(subId);

Refer to Subscribe, Unsubscribe, and MessageIn for more information about subscriptions and receiving messages.

Sending Messages

To send messages, use the SendMessage and SendData methods. SendMessage is used to send messages with string payloads, while SendData is used to send messages with binary payloads.

Send String Message Example stomp1.SendMessage("test/a/b", "Hello, world!");

Send Binary Message Example byte[] fileContent = File.ReadAllBytes("C:\test\stuff.dat"); stomp1.SendData("test/a/b", fileContent);

Refer to SendMessage and SendData for more information about sending messages.

Using Transactions

STOMP transactions are used to group messages together for processing on the server. Messages sent as part of a transaction will not be delivered by the server until the transaction is committed. If the transaction is aborted, the server will discard the messages without attempting to deliver them.

Basic Transaction Example // Open a new transaction. stomp1.BeginTransaction("txn1"); // Set the Transaction property to make sure that messages are sent as part of the transaction. stomp1.Transaction = "txn1"; stomp1.SendMessage("test/a/b", "Hello, world!"); stomp1.SendMessage("test/a/b", "This is a test."); stomp1.SendMessage("test/a/b", "Another test!"); // At this point, none of the messages sent above would have been delivered to any clients // subscribed to the "test/a/b" destination yet, because the transaction is still open. // If we close and commit the transaction, the server will then deliver the messages to subscribers, // queue them, or process them in another manner; the behavior is server-dependent. stomp1.CommitTransaction("txn1"); // Or, the transaction can be aborted, in which case the server will discard the messages // without delivering them to the subscribers. //stomp1.AbortTransaction("txn1"); // Reset (or change) the Transaction property after committing or aborting a transaction // so that future messages are not associated with the previous transaction. stomp1.Transaction = "";

Refer to BeginTransaction for more information about using transactions.

Property List

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

Method List

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

Event List

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

Config Settings

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

Connected Property (STOMP Class)

Triggers a connection or disconnection.

Syntax

public boolean isConnected();


public void setConnected(boolean connected);

Default Value

False

Remarks

This property triggers a connection or disconnection. Setting this property to True makes the class attempt to connect to the host identified by the RemoteHost property. If successful, after the connection is achieved the value of the property changes to True and the Connected event is fired.

Setting this property to False closes the connection.

When connecting to a STOMP server, the class sends information from the following properties, if populated:

• IncomingHeartbeat
• OutgoingHeartbeat
• User
• Password

In addition to the above properties, the following configuration settings can be set before connecting (though in most cases this is not necessary):

• SupportedVersions: Controls which STOMP versions the class advertises support for.
• VirtualHost: Controls the virtual host to connect to. If left empty (default), the value from RemoteHost is used.

This property is not available at design time.

ContentType Property (STOMP Class)

The content type of the outgoing message.

Syntax

public String getContentType();


public void setContentType(String contentType);

Default Value

"text/plain"

Remarks

This property is used to specify the content type (MIME type) for outgoing messages sent using SendMessage. The default value is text/plain, which should be sufficient is most cases.

Note that this property is ignored for messages sent using SendData, as such messages do not have a content-type header added to them. The absence of a content-type header indicates to the server that the data should be treated as a binary blob.

This property is not available at design time.

Firewall Property (STOMP Class)

A set of properties related to firewall access.

Syntax

public Firewall getFirewall();


public void setFirewall(Firewall firewall);

Remarks

This is a Firewall-type property, which contains fields describing the firewall through which the class will attempt to connect.

Headers Property (STOMP Class)

User-defined headers added to outgoing messages.

Syntax

public STOMPHeaderList getHeaders();


public void setHeaders(STOMPHeaderList headers);

Remarks

This property holds a collection of STOMPHeader items representing user-defined headers. The headers in this collection are added to each outgoing message sent with SendMessage or SendData.

Note that the STOMP specification defines a number of standard headers necessary for implementing the STOMP protocol. When constructing an outgoing message, the class silently ignores any user-defined headers that are already set by the class.

This property is not available at design time.

IncomingHeartbeat Property (STOMP Class)

Specifies the server-to-class heartbeat timing.

Syntax

public int getIncomingHeartbeat();


public void setIncomingHeartbeat(int incomingHeartbeat);

Default Value

0

Remarks

This property specifies the incoming heartbeat interval, which is the number of seconds without any server-to-class communication that the server will allow to elapse before sending the class a heartbeat (keepalive). If set to 0 (default), incoming heartbeats are disabled.

For information about outgoing (class-to-server) heartbeats; see the OutgoingHeartbeat property.

Before Connecting

Before connecting, this property is used to specify the desired incoming heartbeat interval (in seconds). By default, this property is set to 0 (no heartbeat).

During the connection process, the incoming heartbeat interval requested by the class is compared to the minimum interval supported by the server, and the larger of the two values is selected. If one or both sides supply 0 as their value, then no server-to-class heartbeats will be sent.

After Connecting

After connecting, this property cannot be set. Instead, it reflects the incoming heartbeat interval agreed upon by the class and the server during the connection process.

As the incoming heartbeat interval negotiation notes above imply, it is possible that the agreed-upon incoming heartbeat interval may either be larger than what the class requested, or may be 0 (i.e., incoming heartbeats are disabled).

This property is not available at design time.

LocalHost Property (STOMP Class)

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

Syntax

public String getLocalHost();


public void setLocalHost(String 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 class initiate connections (or accept in the case of server classs) only through that interface.

If the class 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 (STOMP Class)

The TCP port in the local host where the class binds.

Syntax

public int getLocalPort();


public void setLocalPort(int localPort);

Default Value

0

Remarks

This property must be set before a connection is attempted. It instructs the class to bind to a specific port (or communication endpoint) in the local machine.

Setting this property to 0 (default) enables the system to choose an open port at random. The chosen port will be returned by the LocalPort property after the connection is established.

LocalPort cannot be changed once a connection is made. Any attempt to set this property when a connection is active will generate an error.

This property is useful when trying to connect to services that require a trusted port in the client side.

OutgoingHeartbeat Property (STOMP Class)

Specifies the class-to-server heartbeat timing.

Syntax

public int getOutgoingHeartbeat();


public void setOutgoingHeartbeat(int outgoingHeartbeat);

Default Value

0

Remarks

This property specifies the outgoing heartbeat interval, which is the number of seconds without any class-to-server communication that the class will allow to elapse before sending the server a heartbeat (keepalive). If set to 0 (default), outgoing heartbeats are disabled.

For information about incoming (server-to-class) heartbeats; see the IncomingHeartbeat property.

Before Connecting

Before connecting, this property is used to specify the minimum supported outgoing heartbeat interval (in seconds). By default, this property is set to 0 (no heartbeat).

During the connection process, the minimum outgoing heartbeat interval supported by the class is compared to the interval requested by the server, and the larger of the two values is selected. If one or both sides supply 0 as their value, then no class-to-server heartbeats will be sent.

After Connecting

After connecting, this property cannot be set. Instead, it reflects the outgoing heartbeat interval agreed upon by the class and the server during the connection process.

As the outgoing heartbeat interval negotiation notes above imply, it is possible that the agreed-upon outgoing heartbeat interval may either be larger than the class's supported minimum, or may be 0 (i.e., outgoing heartbeats are disabled).

This property is not available at design time.

ParsedHeaders Property (STOMP Class)

Headers parsed from incoming messages.

Syntax

public STOMPHeaderList getParsedHeaders();

Remarks

This property holds a collection of STOMPHeader items, representing both standard and user-defined headers parsed from incoming messages. It is populated each time the MessageIn event fires, and is cleared after the MessageIn event completes.

Note that the class collapses headers with duplicate key names by default for incoming messages, only keeping the first header for each unique key. This behavior can be controlled using the CollapseHeaders configuration setting.

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

Password Property (STOMP Class)

A password if authentication is to be used.

Syntax

public String getPassword();


public void setPassword(String password);

Default Value

""

Remarks

If this property is set when connecting, the class will send the password in the passcode header.

This property is not available at design time.

ReadyToSend Property (STOMP Class)

Indicates whether the class is ready to send data.

Syntax

public boolean isReadyToSend();

Default Value

False

Remarks

This property indicates that the underlying TCP/IP subsystem is ready to accept data. This is True after connecting to the remote host, and will become False if a call to SendData or SendMessage fails due to a WOULDBLOCK condition.

Once data can be sent again, the ReadyToSend event will fire and this property will be True.

If a WOULDBLOCK error occurs while sending a message the class will automatically complete the transmission when sending is possible. No action needs to be taken to re-send the message. ReadyToSend will fire after the class completes any partially sent messages.

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

RemoteHost Property (STOMP Class)

The address of the remote host. Domain names are resolved to IP addresses.

Syntax

public String getRemoteHost();


public void setRemoteHost(String remoteHost);

Default Value

""

Remarks

This property specifies the IP address (IP number in dotted internet format) or Domain Name of the remote host. It is set before a connection is attempted and cannot be changed once a connection is established.

If this property is set to a Domain Name, a DNS request is initiated, and upon successful termination of the request, this property is set to the corresponding address. If the search is not successful, an error is returned.

If the class is configured to use a SOCKS firewall, the value assigned to this property may be preceded with an "*". If this is the case, the host name is passed to the firewall unresolved and the firewall performs the DNS resolution.

By default the class will connect in plaintext. To enable SSL set SSLEnabled to True.

RemotePort Property (STOMP Class)

The port of the STOMP server (default is 61613). The default port for SSL is 61612.

Syntax

public int getRemotePort();


public void setRemotePort(int remotePort);

Default Value

61613

Remarks

This property specifies a service port on the remote host to connect to.

A valid port number (a value between 1 and 65535) is required for the connection to take place. The property must be set before a connection is attempted and cannot be changed once a connection is established. Any attempt to change this property while connected will fail with an error.

This property is not available at design time.

RequestReceipts Property (STOMP Class)

Whether the class should request that the server provide message receipts.

Syntax

public boolean isRequestReceipts();


public void setRequestReceipts(boolean requestReceipts);

Default Value

False

Remarks

This property is used to specify whether the class should request that the server send back confirmations (known as a "receipts" in STOMP terminology) when it receives messages from the class. This is done by adding a receipt header to the outgoing frame.

When this property is set to True, and a message is sent, the ReceiptOut event will fire immediately after the MessageOut event fires.

Note that, while this property only controls receipt requests for outgoing messages, the class is capable of requesting receipts for any outgoing frame type. Use this table to determine which API members control receipt request for each outgoing frame type (all are False by default):

Received Receipt Notes

When a receipt is received, the ReceiptIn event fires.

Note that receipts are cumulative, and a STOMP server is not required to send back discrete receipts for each frame it receives that has a receipt header. For example, if the class has sent four message frames with the following receipt header values (in chronological order):

1. SEND-3
2. SEND-4
3. SEND-5
4. SEND-6

This property is not available at design time.

SSLAcceptServerCert Property (STOMP Class)

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

Syntax

public Certificate getSSLAcceptServerCert();


public void setSSLAcceptServerCert(Certificate SSLAcceptServerCert);

Remarks

If it finds any issues with the certificate presented by the server, the class 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.

Please note that this functionality is provided only for cases where 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.

SSLCert Property (STOMP Class)

The certificate to be used during SSL negotiation.

Syntax

public Certificate getSSLCert();


public void setSSLCert(Certificate SSLCert);

Remarks

The digital certificate that the class 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 field to the encoded certificate. To select a certificate, use the store and subject fields.

SSLEnabled Property (STOMP Class)

Whether TLS/SSL is enabled.

Syntax

public boolean isSSLEnabled();


public void setSSLEnabled(boolean SSLEnabled);

Default Value

False

Remarks

This setting specifies whether TLS/SSL is enabled in the class. When False (default) the class 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 (STOMP Class)

This specifies the SSL/TLS implementation to use.

Syntax

public int getSSLProvider();


public void setSSLProvider(int SSLProvider);


Enumerated values:
  public final static int sslpAutomatic = 0;
  public final static int sslpPlatform = 1;
  public final static int sslpInternal = 2;

Default Value

0

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 class 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 class will select a provider depending on the current platform.

When Automatic is selected the platform implementation is used by default. When TLS 1.3 is enabled via SSLEnabledProtocols the internal implementation is used.

SSLServerCert Property (STOMP Class)

The server certificate for the last established connection.

Syntax

public Certificate getSSLServerCert();

Remarks

SSLServerCert contains the server certificate for the last established connection.

SSLServerCert is reset every time a new connection is attempted.

This property is read-only.

Subscriptions Property (STOMP Class)

Collection of current subscriptions.

Syntax

public STOMPSubscriptionList getSubscriptions();

Remarks

This property holds a collection of STOMPSubscription items representing the class's current subscriptions.

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

Timeout Property (STOMP Class)

A timeout for the class.

Syntax

public int getTimeout();


public void setTimeout(int timeout);

Default Value

60

Remarks

This property defines the timeout when sending data. When SSLEnabled is False a value of 0 means data will be sent asynchronously and a positive value means data is sent synchronously. When SSLEnabled is True all data is sent synchronously regardless of the Timeout value. Please see the notes below for details.

Plaintext

If the Timeout property is set to 0, all operations return immediately, potentially failing with a WOULDBLOCK error if data cannot be sent immediately.

If Timeout is set to a positive value, data is sent in a blocking manner and the class will wait for the operation to complete before returning control. The class will handle any potential WOULDBLOCK errors internally and automatically retry the operation for a maximum of Timeout seconds.

SSL

If the Timeout property is set to 0, all operations will run uninterrupted until successful completion or an error condition is encountered.

If Timeout is set to a positive value, the class will wait for the operation to complete before returning control.

Additional Notes

The class will use DoEvents to enter an efficient wait loop during any potential waiting period, making sure 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 operation is not yet complete, the class throws an exception.

Please note that by default, all timeouts are inactivity timeouts, i.e. the timeout period is extended by Timeout seconds when any amount of data is successfully sent or received.

The default value for the Timeout property is 60 seconds.

TransactionId Property (STOMP Class)

Specifies the Id of the transaction that outgoing messages are associated with.

Syntax

public String getTransactionId();


public void setTransactionId(String transactionId);

Default Value

""

Remarks

This property, if not empty, is used to specify which transaction outgoing messages sent using SendMessage or SendData are associated with.

This property must either be empty, or set to the Id of a currently open transaction. The OpenTransactions configuration setting can be queried at any time to retrieve a comma-separated list of currently open transactions' Ids.

Note that this property only affects outgoing messages. It is also possible to send a message acknowledgment as part of a transaction by setting the AckTransactionId configuration setting during the MessageIn event handler.

Refer to BeginTransaction for more information about transactions.

This property is not available at design time.

User Property (STOMP Class)

A username if authentication is to be used.

Syntax

public String getUser();


public void setUser(String user);

Default Value

""

Remarks

If this property is set when connecting, the class will send the user in the login header.

This property is not available at design time.

AbortTransaction Method (Stomp Class)

Aborts an existing transaction.

Syntax

public void abortTransaction(String id);

Remarks

This method aborts a transaction previously started with BeginTransaction. Id identifies the transaction to abort.

The OpenTransactions configuration setting can be queried to obtain a list of currently-open transactions.

Refer to BeginTransaction for more information about transactions.

AddHeader Method (Stomp Class)

Adds a custom header to send with outgoing messages.

Syntax

public void addHeader(String key, String value);

Remarks

This method is used to add user-defined headers to the list of headers held by the Headers collection property.

When SendMessage or SendData is called, all headers in the Headers collection property are added to the outgoing message.

Note that the STOMP specification defines a number of standard headers necessary for implementing the STOMP protocol. When constructing an outgoing message, the class silently ignores any user-defined headers that are already set by the class.

BeginTransaction Method (Stomp Class)

Begins a new transaction.

Syntax

public void beginTransaction(String id);

Remarks

This method begins a new transaction using the specified Id, which must be unique. There is no limit to how many transactions may be open at any given time.

A transaction is a group of messages and message acknowledgments which are all processed atomically when the transaction is committed or aborted.

Messages sent in a transaction will not be delivered to clients subscribed to the messages' destinations until the transaction is committed.

Since it is possible for multiple transactions to be open at any given time, the TransactionId property is used to specify which transaction (if any) messages should be sent in. Similarly, message acknowledgments can be sent in a transaction by setting the AckTransactionId configuration setting during the MessageIn event handler.

The OpenTransactions configuration setting can be queried at any time to retrieve a comma-separated list of currently open transactions' Ids.

Basic Transaction Example // Open a new transaction. stomp1.BeginTransaction("txn1"); // Set the Transaction property to make sure that messages are sent as part of the transaction. stomp1.Transaction = "txn1"; stomp1.SendMessage("test/a/b", "Hello, world!"); stomp1.SendMessage("test/a/b", "This is a test."); stomp1.SendMessage("test/a/b", "Another test!"); // At this point, none of the messages sent above would have been delivered to any clients // subscribed to the "test/a/b" destination yet, because the transaction is still open. // If we close and commit the transaction, the server will then deliver the messages to subscribers, // queue them, or process them in another manner; the behavior is server-dependent. stomp1.CommitTransaction("txn1"); // Or, the transaction can be aborted, in which case the server will discard the messages // without delivering them to the subscribers. //stomp1.AbortTransaction("txn1"); // Reset (or change) the Transaction property after committing or aborting a transaction // so that future messages are not associated with the previous transaction. stomp1.Transaction = "";

CommitTransaction Method (Stomp Class)

Commits an existing transaction.

Syntax

public void commitTransaction(String id);

Remarks

This method commits a transaction previously started with BeginTransaction. Id identifies the transaction to commit.

The OpenTransactions configuration setting can be queried to obtain a list of currently-open transactions.

Refer to BeginTransaction for more information about transactions.

Config Method (Stomp Class)

Sets or retrieves a configuration setting.

Syntax

public String config(String configurationString);

Remarks

Config is a generic method available in every class. It is used to set and retrieve configuration settings for the class.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, 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.

Connect Method (Stomp Class)

Connects to the remote host.

Syntax

public void connect();

Remarks

This method connects to the remote host, specified by RemoteHost and RemotePort. Calling this method is equivalent to setting the Connected property to True.

By default the class will connect in plaintext. To enable SSL set SSLEnabled to True.

When connecting to a STOMP server, the class sends information from the following properties, if populated:

• IncomingHeartbeat
• OutgoingHeartbeat
• User
• Password

In addition to the above properties, the following configuration settings can be set before connecting (though in most cases this is not necessary):

• SupportedVersions: Controls which STOMP versions the class advertises support for.
• VirtualHost: Controls the virtual host to connect to. If left empty (default), the value from RemoteHost is used.

ConnectTo Method (Stomp Class)

Connects to the remote host.

Syntax

public void connectTo(String host, int port);

Remarks

This method connects to the remote host specified by the Host and Port parameters. Calling this method is equivalent to setting the RemoteHost property to Host, setting RemotePort to Port, and then setting the Connected property to True.

By default the class will connect in plaintext. To enable SSL set SSLEnabled to True.

When connecting to a STOMP server, the class sends information from the following properties, if populated:

• IncomingHeartbeat
• OutgoingHeartbeat
• User
• Password

In addition to the above properties, the following configuration settings can be set before connecting (though in most cases this is not necessary):

• SupportedVersions: Controls which STOMP versions the class advertises support for.
• VirtualHost: Controls the virtual host to connect to. If left empty (default), the value from RemoteHost is used.

Disconnect Method (Stomp Class)

This method disconnects from the remote host.

Syntax

public void disconnect();

Remarks

This method disconnects from the remote host. Calling this method is equivalent to setting the Connected property to False.

DoEvents Method (Stomp Class)

Processes events from the internal message queue.

Syntax

public void doEvents();

Remarks

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

Interrupt Method (Stomp Class)

Interrupt the current action and disconnects from the remote host.

Syntax

public void interrupt();

Remarks

This method will interrupt the current method (if applicable) and cause the class to disconnect from the remote host.

Reset Method (Stomp Class)

Reset the class.

Syntax

public void reset();

Remarks

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

ResetHeaders Method (Stomp Class)

Clear the user-defined headers collection.

Syntax

public void resetHeaders();

Remarks

This method clears the Headers collection property.

SendData Method (Stomp Class)

Publishes a message with a raw data payload.

Syntax

public void sendData(String destination, byte[] data);

Remarks

This method publishes a STOMP message with a raw data payload to the specified Destination. The MessageOut event will fire after the message has been sent.

The STOMP specification does not place any restrictions on Destination names. Instead, each STOMP server is free to define its own requirements for, and/or interpretations of, a Destination name; for example, a server might prohibit certain characters, require a specific format, or interpret some patterns in a special manner. Be sure to consult the documentation for your STOMP server to determine how to build proper Destination names.

In addition to the payload, the outgoing messages will include:

• All user-defined headers held by the Headers collection property.
• If the TransactionId property is populated, the transaction Id that it specifies (which associates the message with that transaction).

If RequestReceipts is enabled when this method is called, the class will request that the server send back a receipt to confirm it has received the message. Refer to RequestReceipts for more information.

Note that no content type is defined for raw data payload messages; so the ContentType property is ignored by this method.

Send String Message Example stomp1.SendMessage("test/a/b", "Hello, world!");

Send Binary Message Example byte[] fileContent = File.ReadAllBytes("C:\test\stuff.dat"); stomp1.SendData("test/a/b", fileContent);

SendMessage Method (Stomp Class)

Publishes a message with a string payload.

Syntax

public void sendMessage(String destination, String message);

Remarks

This method publishes a STOMP message with a string payload to the specified Destination. The MessageOut event will fire after the message has been sent.

The ContentType property can be used to specify the content type of the payload. By default, ContentType is set to text/plain.

The STOMP specification does not place any restrictions on Destination names. Instead, each STOMP server is free to define its own requirements for, and/or interpretations of, a Destination name; for example, a server might prohibit certain characters, require a specific format, or interpret some patterns in a special manner. Be sure to consult the documentation for your STOMP server to determine how to build proper Destination names.

In addition to the payload, the outgoing messages will include:

• All user-defined headers held by the Headers collection property.
• If the TransactionId property is populated, the transaction Id that it specifies (which associates the message with that transaction).

If RequestReceipts is enabled when this method is called, the class will request that the server send back a receipt to confirm it has received the message. Refer to RequestReceipts for more information.

Send String Message Example stomp1.SendMessage("test/a/b", "Hello, world!");

Send Binary Message Example byte[] fileContent = File.ReadAllBytes("C:\test\stuff.dat"); stomp1.SendData("test/a/b", fileContent);

Subscribe Method (Stomp Class)

Subscribes to a message destination on the server.

Syntax

public String subscribe(String destination, boolean requireAcks);

Remarks

This method is used to subscribe to the specified message Destination on the server. The Id of the subscription is returned.

Once subscribed, the Subscribed event will fire and an item will be added to the Subscriptions collection property. The MessageIn event will fire anytime a message is received for any subscription.

The STOMP specification does not place any restrictions on Destination names. Instead, each STOMP server is free to define its own requirements for, and/or interpretations of, a Destination name; for example, a server might prohibit certain characters, require a specific format, or interpret some patterns in a special manner. Be sure to consult the documentation for your STOMP server to determine how to build proper Destination names.

If the RequireAcks parameter is set to True, the server will expect the class to send it a message acknowledgment for each message it delivers as part of this subscription. (Refer to the MessageIn event for more information about sending message acknowledgments).

Basic Subscriptions Example stomp1.OnMessageIn += (s, e) => { Console.WriteLine("Received message from destination '" + e.Destination + "':"); Console.WriteLine(e.Data); }; string subId = stomp1.Subscribe("test/a/b", false); // Some time later... stomp1.Unsubscribe(subId);

Unsubscribe Method (Stomp Class)

Removes an existing subscription.

Syntax

public void unsubscribe(String id);

Remarks

This method removes an existing subscription identified by the given Id, unsubscribing the class from the destination associated with the subscription.

Once unsubscribed, the relevant item will be removed from the Subscriptions collection property and the Unsubscribed event will fire.

Basic Subscriptions Example stomp1.OnMessageIn += (s, e) => { Console.WriteLine("Received message from destination '" + e.Destination + "':"); Console.WriteLine(e.Data); }; string subId = stomp1.Subscribe("test/a/b", false); // Some time later... stomp1.Unsubscribe(subId);

Connected Event (Stomp Class)

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

Syntax

public class DefaultStompEventListener implements StompEventListener {
  ...
  public void connected(StompConnectedEvent e) {}
  ...
}

public class StompConnectedEvent {
  public int statusCode;
  public String description;
}

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 Transmission Control Protocol (TCP)/IP stack. Description contains a description of this code. The value of StatusCode is equal to the value of the error.

Please refer to the Error Codes section for more information.

ConnectionStatus Event (Stomp Class)

This event is fired to indicate changes in the connection state.

Syntax

public class DefaultStompEventListener implements StompEventListener {
  ...
  public void connectionStatus(StompConnectionStatusEvent e) {}
  ...
}

public class StompConnectionStatusEvent {
  public String connectionEvent;
  public int statusCode;
  public String description;
}

Remarks

The ConnectionStatus event is fired when the connection state changes: for example, completion of a firewall or proxy connection or completion of a security handshake.

The ConnectionEvent parameter indicates the type of connection event. Values may include the following:

Disconnected Event (Stomp Class)

This event is fired when a connection is closed.

Syntax

public class DefaultStompEventListener implements StompEventListener {
  ...
  public void disconnected(StompDisconnectedEvent e) {}
  ...
}

public class StompDisconnectedEvent {
  public int statusCode;
  public String description;
}

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 Transmission Control Protocol (TCP/IP) subsystem. Description contains a description of this code. The value of StatusCode is equal to the value of the TCP/IP error.

Please refer to the Error Codes section for more information.

Error Event (Stomp Class)

Fired when a class or protocol error occurs.

Syntax

public class DefaultStompEventListener implements StompEventListener {
  ...
  public void error(StompErrorEvent e) {}
  ...
}

public class StompErrorEvent {
  public int errorCode;
  public String description;
  public byte[] data;
}

Remarks

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

STOMP Protocol Errors

When this occurs, ErrorCode will be 600, Description will reflect the value of the ERROR frame's message header, and Data will contain the body of the ERROR frame (if one is present).

The ErrorHeaders configuration setting will also be populated with the raw headers from the ERROR frame for the duration of the Error event handler.

Log Event (Stomp Class)

Fired once for each log message.

Syntax

public class DefaultStompEventListener implements StompEventListener {
  ...
  public void log(StompLogEvent e) {}
  ...
}

public class StompLogEvent {
  public int logLevel;
  public String message;
  public String logType;
}

Remarks

This event fires once for each log message generated by the class. The verbosity is controlled by the LogLevel setting.

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

LogType identifies the type of log entry. Possible values are:

• Info: General information about the class.
• Acknowledgment: Information about outgoing message acknowledgments.
• Frame: Frame content logging.

MessageIn Event (Stomp Class)

Fired when a message has been received.

Syntax

public class DefaultStompEventListener implements StompEventListener {
  ...
  public void messageIn(StompMessageInEvent e) {}
  ...
}

public class StompMessageInEvent {
  public String messageId;
  public String subscriptionId;
  public String destination;
  public byte[] data;
  public String contentType;
  public boolean ack;
}

Remarks

This events fires whenever the class has received a message.

In addition to the message details exposed by the event parameters, the ParsedHeaders collection property is populated with the headers parsed from the message. When the MessageIn event handler exits, the parsed headers are cleared. The following parameters are available within this event:

• MessageId: The unique Id of the message.
• SubscriptionId: The subscription Id the message is associated with.
• Destination: The message destination on the server which the message originated from.
• Data: The message's payload.
• ContentType: The content type of the message (may be empty).
• Ack: Set to True or False to control whether the class should send back a positive (True, default) or negative (False) message acknowledgment.

Message acknowledgments are only sent back to the server for messages which require them. A positive acknowledgment indicates that the message has been accepted, while a negative acknowledgment represents that the message has been rejected.

The following two configuration settings are also relevant in the context of sending back message acknowledgments for incoming messages:

• The AckTransactionId configuration setting, if not empty, specifies a transaction Id to associate the message acknowledgment with. It can only be set during the MessageIn event handler, and will be reset when the event handler ends.
• The RequestAckReceipts configuration setting controls whether the class will request that the server confirm receipt of the message acknowledgment. It is False by default, and can be set at any time.

MessageOut Event (Stomp Class)

Fired after a message has been sent.

Syntax

public class DefaultStompEventListener implements StompEventListener {
  ...
  public void messageOut(StompMessageOutEvent e) {}
  ...
}

public class StompMessageOutEvent {
  public String destination;
  public byte[] data;
  public String contentType;
}

Remarks

This event fires after a message has been sent using either SendMessage or SendData. The following parameters are available within this event:

• Destination: The destination the message was sent to.
• Data: The message's payload.
• ContentType: The content type of the message (always empty for messages sent with SendData).

ReadyToSend Event (Stomp Class)

Fired when the class is ready to send data.

Syntax

public class DefaultStompEventListener implements StompEventListener {
  ...
  public void readyToSend(StompReadyToSendEvent e) {}
  ...
}

public class StompReadyToSendEvent {
}

Remarks

The ReadyToSend event indicates that the underlying TCP/IP subsystem is ready to accept data after a call to SendData or SendMessage fails due to a WOULDBLOCK condition. The event is also fired immediately after a connection to the remote host is established.

ReceiptIn Event (Stomp Class)

Fires when the class receives a receipt from the server.

Syntax

public class DefaultStompEventListener implements StompEventListener {
  ...
  public void receiptIn(StompReceiptInEvent e) {}
  ...
}

public class StompReceiptInEvent {
  public String receiptId;
}

Remarks

This event fires anytime the class receives a receipt (that is, a confirmation that the server has received one or more frames) from the server. The ReceiptId parameter reflects the value of the receipt-id header in the incoming RECEIPT frame.

Note that receipts are cumulative, and a STOMP server is not required to send back discrete receipts for each frame it receives that has a receipt header. For example, if the class has sent four message frames with the following receipt header values (in chronological order):

1. SEND-3
2. SEND-4
3. SEND-5
4. SEND-6

Refer to RequestReceipts for more information about receipts.

ReceiptOut Event (Stomp Class)

Fires when the class sends a STOMP frame that includes a 'receipt' header.

Syntax

public class DefaultStompEventListener implements StompEventListener {
  ...
  public void receiptOut(StompReceiptOutEvent e) {}
  ...
}

public class StompReceiptOutEvent {
  public String receiptId;
}

Remarks

This event fires anytime the class sends any STOMP frame that includes a receipt header on it. The ReceiptId parameter reflects the value of the receipt header.

Having a receipt header on an outgoing frame indicates to the server that it should send back a receipt to confirm that it has received the frame (though it is not required to do so immediately; see ReceiptIn for details). Anytime the server sends back a receipt, the ReceiptIn event will fire.

Refer to RequestReceipts for more information about receipts.

SSLServerAuthentication Event (Stomp Class)

Fired after the server presents its certificate to the client.

Syntax

public class DefaultStompEventListener implements StompEventListener {
  ...
  public void SSLServerAuthentication(StompSSLServerAuthenticationEvent e) {}
  ...
}

public class StompSSLServerAuthenticationEvent {
  public byte[] certEncoded;
  public String certSubject;
  public String certIssuer;
  public String status;
  public boolean accept;
}

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 (Stomp Class)

Shows the progress of the secure connection.

Syntax

public class DefaultStompEventListener implements StompEventListener {
  ...
  public void SSLStatus(StompSSLStatusEvent e) {}
  ...
}

public class StompSSLStatusEvent {
  public String message;
}

Remarks

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

Subscribed Event (Stomp Class)

Fired when the class has subscribed to a message destination on the server.

Syntax

public class DefaultStompEventListener implements StompEventListener {
  ...
  public void subscribed(StompSubscribedEvent e) {}
  ...
}

public class StompSubscribedEvent {
  public String id;
  public String destination;
  public boolean requireAcks;
}

Remarks

This event fires each time the class has subscribed to a message destination on the server. The following parameters are available within this event:

• Id: The Id used to identify the subscription.
• Destination: The message destination on the server which the subscription is associated with.
• RequireAcks: Whether messages the class receives as a result of the subscription will require acknowledgments to be sent back to the server.

Unsubscribed Event (Stomp Class)

Fired when the class has unsubscribed from a message destination on the server.

Syntax

public class DefaultStompEventListener implements StompEventListener {
  ...
  public void unsubscribed(StompUnsubscribedEvent e) {}
  ...
}

public class StompUnsubscribedEvent {
  public String id;
  public String destination;
}

Remarks

This event fires each time the class has unsubscribed from a message destination on the server. The following parameters are available within this event:

• Id: The Id that was used to identify the subscription.
• Destination: The message destination on the server which the subscription was associated with.

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.

Fields

Constructors

public Certificate();

Creates a Certificate instance whose properties can be set. This is useful for use with CERTMGR when generating new certificates.

public Certificate( certificateFile);

Opens CertificateFile and reads out the contents as an X509 public key.

public Certificate( certificateData);

Parses CertificateData as an X509 public key.

public Certificate( certStoreType,  store,  storePassword,  subject);

CertStoreType identifies the type of certificate store to use. See StoreType 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 class will attempt to find the certificate identified by Subject . This can be either a complete or a substring match of the X509 certificate's subject Distinguished Name (DN).

public Certificate( certStoreType,  store,  storePassword,  subject,  configurationString);

CertStoreType identifies the type of certificate store to use. See StoreType 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 CyrptoAPI option. The default value is True (the key is persisted). "Thumbprint" - a MD5, SHA1, or SHA256 thumbprint of the certificate to load. When specified, this value is used to select the certificate in the store. This is applicable to 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 class will attempt to find the certificate identified by Subject . This can be either a complete or a substring match of the X509 certificate's subject Distinguished Name (DN).

public Certificate( certStoreType,  store,  storePassword,  encoded);

CertStoreType identifies the type of certificate store to use. See StoreType 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 class will load Encoded as an X509 certificate and search the opened store for a corresponding private key.

public Certificate( certStoreType,  storeBlob,  storePassword,  subject);

CertStoreType identifies the type of certificate store to use. See StoreType for descriptions of the different certificate stores. StoreBlob is a string (binary- or base64-encoded) containing the certificate data. StorePassword is the password used to protect the store. After the store has been successfully opened, the class will attempt to find the certificate identified by Subject . This can be either a complete or a substring match of the X509 certificate's subject Distinguished Name (DN).

public Certificate( certStoreType,  storeBlob,  storePassword,  subject,  configurationString);

CertStoreType identifies the type of certificate store to use. See StoreType for descriptions of the different certificate stores. StoreBlob is a string (binary- or base64-encoded) containing the certificate data. StorePassword is the password used to protect the store. After the store has been successfully opened, the class will attempt to find the certificate identified by Subject . This can be either a complete or a substring match of the X509 certificate's subject Distinguished Name (DN).

public Certificate( certStoreType,  storeBlob,  storePassword,  encoded);

CertStoreType identifies the type of certificate store to use. See StoreType for descriptions of the different certificate stores. Store is a string (binary- or base64-encoded) containing the certificate store. StorePassword is the password used to protect the store. After the store has been successfully opened, the class will load Encoded as an X509 certificate and search the opened store for a corresponding private key.

Firewall Type

This is the firewall the class will connect through.

Remarks

When connecting through a firewall, this type is used to specify different properties of the firewall, such as the firewall Host and the FirewallType.

Fields

Constructors

public Firewall();

STOMPHeader Type

A STOMP header.

Remarks

This type represents a STOMP header.

Fields

Constructors

public STOMPHeader();

public STOMPHeader( key,  value);

STOMPSubscription Type

A STOMP subscription.

Remarks

This type represents a STOMP subscription.

Fields

Config Settings (Stomp Class)

STOMP Config Settings

TCPClient 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-----

Socket Config Settings

Base Config Settings

Trappable Errors (Stomp Class)

STOMP Errors

TCPClient Errors

SSL Errors

TCP/IP Errors