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Net::STOMP::Client(3) User Contributed Perl Documentation Net::STOMP::Client(3)

Net::STOMP::Client - STOMP object oriented client module

  #
  # simple producer
  #

  use Net::STOMP::Client;

  $stomp = Net::STOMP::Client->new(host => "127.0.0.1", port => 61613);
  $stomp->connect(login => "guest", passcode => "guest");
  $stomp->send(destination => "/queue/test", body => "hello world!");
  $stomp->disconnect();

  #
  # consumer with client side acknowledgment
  #

  use Net::STOMP::Client;

  $stomp = Net::STOMP::Client->new(host => "127.0.0.1", port => 61613);
  $stomp->connect(login => "guest", passcode => "guest");
  # declare a callback to be called for each received message frame
  $stomp->message_callback(sub {
      my($self, $frame) = @_;
      $self->ack(frame => $frame);
      printf("received: %s\n", $frame->body());
      return($self);
  });
  # subscribe to the given queue
  $stomp->subscribe(
      destination => "/queue/test",
      id          => "testsub",          # required in STOMP 1.1
      ack         => "client",           # client side acknowledgment
  );
  # wait for a specified message frame
  $stomp->wait_for_frames(callback => sub {
      my($self, $frame) = @_;
      if ($frame->command() eq "MESSAGE") {
          # stop waiting for new frames if body is "quit"
          return(1) if $frame->body() eq "quit";
      }
      # continue to wait for more frames
      return(0);
  });
  $stomp->unsubscribe(id => "testsub");
  $stomp->disconnect();

This module provides an object oriented client interface to interact with servers supporting STOMP (Streaming Text Orientated Messaging Protocol). It supports the major features of modern messaging brokers: SSL, asynchronous I/O, receipts and transactions.

The new() method can be used to create a Net::STOMP::Client object that will later be used to interact with a server. The following attributes are supported:
"accept_version"
the STOMP version to use (string) or versions to use (reference to a list of strings); this defaults to the list of all supported versions; see Net::STOMP::Client::Version for more information
"version"
this attribute is obsolete and should not be used anymore, use "accept_version" instead; it is left here only to provide backward compatibility with Net::STOMP::Client 1.x
"uri"
the Uniform Resource Identifier (URI) specifying where the STOMP service is and how to connect to it, this can be for instance "tcp://msg01:6163" or something more complex, see Net::STOMP::Client::Connection for more information
"host"
the server name or IP address
"port"
the port number of the STOMP service
"auth"
the authentication credential(s) to use, see Net::STOMP::Client::Auth for more information
"sockopts"
arbitrary socket options (as a hash reference) that will be passed to IO::Socket::INET->new() or IO::Socket::SSL->new()
"client_heart_beat"
the desired client-side heart-beat setting, see Net::STOMP::Client::HeartBeat for more information
"server_heart_beat"
the desired server-side heart-beat setting, see Net::STOMP::Client::HeartBeat for more information
"debug"
the debugging flags for this object, see the "DEBUGGING" section for more information
"timeout"
the maximum time (in seconds) for various operations, see the "TIMEOUTS" section for more information

Upon object creation, a TCP connection is made to the server but no data (i.e. STOMP frame) is exchanged.

Net::STOMP::Client uses No::Worries::Log's log_debug() to log debugging information. In addition, to avoid useless data massaging, it also uses a debug string to specify what will be logged using log_debug().

The debug string should contain a list of words describing what to log. For instance, "io" logs I/O information while "io connection" logs both I/O and connection information.

Here are the supported debug words that can be used:

"all"
everything
"api"
high-level API calls
"body"
frame bodies
"command"
frame commands
"connection"
connection establishment
"header"
frame headers
"io"
I/O as bytes sent/received

To enable debugging, you must first configure No::Worries::Log so that it indeed reports debugging messages. This can be done with something like:

  log_filter("debug");

or, to enable logging only from Net::STOMP::Client modules:

  log_filter("debug caller=~^Net::STOMP::Client");

See the No::Worries::Log documentation for more information.

Then, you have to tell Net::STOMP::Client to indeed log what you want to see. This can be done globally for all connections by setting the global variable $Net::STOMP::Client::Debug:

  $Net::STOMP::Client::Debug = "connection api";

or per connection via the new() method:

  $stomp = Net::STOMP::Client->new(
      uri   => "stomp://mybroker:6163",
      debug => "connection api",
  );

By default, when sending STOMP frames, the module waits until the frame indeed has been sent (from the socket point of view). In case the server is stuck or unusable, the module can therefore hang.

When creating the Net::STOMP::Client object, you can pass a "timeout" attribute to better control how certain operations handle timeouts.

This attribute should contain a reference to hash with the following keys:

connect
TCP-level timeout that will be given to the underlying IO::Socket::INET or IO::Socket::SSL object (default: none)
connected
timeout used while waiting for the initial "CONNECTED" frame from the broker (default: 10)
disconnect
timeout specifying how long the disconnect() method should wait for a "RECEIPT" frame back in case the "DISCONNECT" frame contained a receipt (default: 10)
receive
timeout used while trying to receive any frame (default: none)
send
timeout used while trying to send any frame (default: none)

All values are in seconds. No timeout means wait until the operation succeeds.

As a shortcut, the "timeout" attribute can also be a scalar. In this case, only the "connect" and "connected" operations use this value.

With a Net::STOMP::Client object, the following methods can be used to interact with the server. They match one-to-one the different commands that a client frame can hold:
connect()
connect to server
disconnect()
disconnect from server
subscribe()
subscribe to something
unsubscribe()
unsubscribe from something
send()
send a message somewhere
ack()
acknowledge the reception of a message
nack()
acknowledge the rejection of a message (STOMP >=1.1 only)
begin()
begin/start a transaction
commit()
commit a transaction
abort()
abort/rollback a transaction

All these methods can receive options that will be passed directly as frame headers. For instance:

  $stomp->subscribe(
      destination => "/queue/test",
      id          => "testsub",
      ack         => "client",
  );

Some methods also support additional options:

send()
"body" or "body_reference": holds the body or body reference of the message to be sent
ack()
"frame": holds the "MESSAGE" frame object to ack
nack()
"frame": holds the "MESSAGE" frame object to nack

Finally, all methods support "debug" and "timeout" options that will be given to the send_frame() method called internally to send the crafted frame.

In addition to the STOMP methods, the following ones are also available:
new(OPTIONS)
return a new Net::STOMP::Client object (constructor)
peer()
return a Net::STOMP::Client::Peer object containing information about the connected STOMP server
socket()
return the file handle of the socket connecting the client and the server
server()
return the server header seen on the "CONNECTED" frame (if any)
session()
return the session identifier if connected or false otherwise
uuid()
return a universal pseudo-unique identifier to be used for instance in receipts and transactions
wait_for_frames()
wait for frames coming from the server, see the next section for more information
noop([timeout => TIMEOUT])
send an empty/noop frame i.e. a single newline byte, using send_frame() underneath

Since STOMP is asynchronous (for instance, "MESSAGE" frames could be sent by the server at any time), Net::STOMP::Client uses callbacks to handle frames. There are in fact two levels of callbacks.

First, there are per-command callbacks that will be called each time a frame is handled (via the internal dispatch_frame() method). Net::STOMP::Client implements default callbacks that should be sufficient for all frames except "MESSAGE" frames, which should really be handled by the coder. These callbacks should return undef on error, something else on success.

Here is an example with a callback counting the messages received:

  $stomp->message_callback(sub {
      my($self, $frame) = @_;
      $MessageCount++;
      return($self);
  });

Here are the methods that can be used to get or set these per-command callbacks:

connected_callback([SUBREF])
error_callback([SUBREF])
message_callback([SUBREF])
receipt_callback([SUBREF])

These callbacks are somehow global and it is good practice not to change them during a session. If you do not need a global message callback, you can supply the dummy:

  $stomp->message_callback(sub { return(1) });

Then, the wait_for_frames() method takes an optional callback argument holding some code to be called for each received frame, after the per-command callback has been called. This can be seen as a local callback, only valid for the call to wait_for_frames(). This callback must return undef on error, false if more frames are expected or true if wait_for_frames() can now stop waiting for new frames and return.

Here are all the options that can be given to wait_for_frames():

callback
code to be called for each received frame (see above)
timeout
time to wait before giving up, undef means wait forever, this is the default
once
wait only for one frame, within the given timeout

The return value of wait_for_frames() can be: false if no suitable frame has been received, the received frame if there is no user callback or the user callback return value otherwise.

Here is an example using transactions:

  # create a unique transaction id
  $tid = $stomp->uuid();
  # begin the transaction
  $stomp->begin(transaction => $tid);
  # send two messages as part of this transaction
  $stomp->send(
      destination => "/queue/test1",
      body        => "message 1",
      transaction => $tid,
  );
  $stomp->send(
      destination => "/queue/test2",
      body        => "message 2",
      transaction => $tid,
  );
  # commit the transaction
  $stomp->commit(transaction => $tid);

It should be enough to use the high-level API and use, for instance, the send() method to create a "MESSAGE" frame and send it in one go.

If you need lower level interaction, you can manipulate frames with the Net::STOMP::Client::Frame module.

You can also use:

$stomp->dispatch_frame(FRAME, [OPTIONS])
dispatch one received frame by calling the appropriate callback; supported options: "debug"
$stomp->send_frame(FRAME, [OPTIONS])
try to send the given frame object; supported options: "timeout" and "debug"
$stomp->send_message(MESSAGE, [OPTIONS])
identical to send_frame() but taking a Messaging::Message object
$stomp->queue_frame(FRAME, [OPTIONS])
add the given frame to the outgoing buffer queue; supported options: "debug"
$stomp->queue_message(MESSAGE, [OPTIONS])
identical to queue_frame() but taking a Messaging::Message object
$stomp->send_data([OPTIONS])
send all the queued data; supported options: "timeout" and "debug"
$stomp->receive_frame([OPTIONS])
try to receive a frame; supported options: "timeout" and "debug"
$stomp->receive_data([OPTIONS])
try to receive data (this data will be appended to the incoming buffer); supported options: "timeout" and "debug"
$stomp->outgoing_buffer_length()
return the length (in bytes) of the outgoing buffer
$stomp->incoming_buffer_reference()
return a reference to the incoming buffer

In these methods, the "timeout" option can either be "undef" (meaning block until it's done) or 0 (meaning do not block at all) or a positive number (meaning block at most this number of seconds).

This module has been successfully tested against ActiveMQ, Apollo, HornetQ and RabbitMQ brokers.

See Net::STOMP::Client::Version for the list of supported STOMP protocol versions.

Messaging::Message, Net::STOMP::Client::Auth, Net::STOMP::Client::Connection, Net::STOMP::Client::Frame, Net::STOMP::Client::HeartBeat, Net::STOMP::Client::Peer, Net::STOMP::Client::Receipt, Net::STOMP::Client::Tutorial, Net::STOMP::Client::Version, No::Worries::Log.

Lionel Cons <http://cern.ch/lionel.cons>

Copyright (C) CERN 2010-2017

2017-01-31 perl v5.32.1

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