NAME
AnyEvent::Stomper - Flexible non-blocking STOMP client
SYNOPSIS
use AnyEvent;
use AnyEvent::Stomper;
my $stomper = AnyEvent::Stomper->new(
host => 'localhost',
prot => '61613',
login => 'guest',
passcode => 'guest',
);
my $cv = AE::cv;
$stomper->subscribe(
id => 'foo',
destination => '/queue/foo',
on_receipt => sub {
my $err = $_[1];
if ( defined $err ) {
warn $err->message . "\n";
$cv->send;
return;
}
$stomper->send(
destination => '/queue/foo',
body => 'Hello, world!',
);
},
on_message => sub {
my $msg = shift;
my $body = $msg->body;
print "Consumed: $body\n";
$cv->send;
}
);
$cv->recv;
DESCRIPTION
AnyEvent::Stomper is flexible non-blocking STOMP client. Supports following STOMP versions: 1.0, 1.1, 1.2.
Is recommended to read STOMP protocol specification before using the client: https://stomp.github.io/index.html
CONSTRUCTOR
new( %params )
my $stomper = AnyEvent::Stomper->new(
host => 'localhost',
port => '61613',
login => 'guest',
passcode => 'guest',
vhost => '/',
heartbeat => [ 5000, 5000 ],
connection_timeout => 5,
lazy => 1,
reconnect_interval => 5,
on_connect => sub {
# handling...
},
on_disconnect => sub {
# handling...
},
on_error => sub {
my $err = shift;
# error handling...
},
);
- host => $host
-
Server hostname (default: localhost)
- port => $port
-
Server port (default: 61613)
- login => $login
-
The user identifier used to authenticate against a secured STOMP server.
- passcode => $passcode
-
The password used to authenticate against a secured STOMP server.
- vhost => $vhost
-
The name of a virtual host that the client wishes to connect to.
- heartbeat => \@heartbeat
-
Heart-beating can optionally be used to test the healthiness of the underlying TCP connection and to make sure that the remote end is alive and kicking. The first number sets interval in milliseconds between outgoing heart-beats to the STOMP server.
0
means, that the client will not send heart-beats. The second number sets interval in milliseconds between incoming heart-beats from the STOMP server.0
means, that the client does not want to receive heart-beats.heartbeat => [ 5000, 5000 ],
Not set by default.
- connection_timeout => $connection_timeout
-
Specifies connection timeout. If the client could not connect to the server after specified timeout, the
on_error
callback is called with theE_CANT_CONN
error. The timeout specifies in seconds and can contain a fractional part.connection_timeout => 10.5,
By default the client use kernel's connection timeout.
- lazy => $boolean
-
If enabled, the connection establishes at time when you will send the first command to the server. By default the connection establishes after calling of the
new
method.Disabled by default.
- reconnect_interval => $reconnect_interval
-
If the connection to the server was lost, the client will try to restore the connection when you execute next command. By default reconnection is performed immediately, on next command execution. If the
reconnect_interval
parameter is specified, the client will try to reconnect only after this interval and commands executed between reconnections will be queued.The client will try to reconnect only once and, if attempt fails, the error object is passed to command callback. If you need several attempts of the reconnection, you must retry a command from the callback as many times, as you need.
reconnect_interval => 5,
Not set by default.
- handle_params => \%params
-
Specifies AnyEvent::Handle parameters.
handle_params => { autocork => 1, linger => 60, }
Enabling of the
autocork
parameter can improve performance. See documentation on AnyEvent::Handle for more information. - default_headers => \%headers
-
Specifies default headers for all outgoing frames.
default_headers => { 'x-foo' => 'foo_value', 'x-bar' => 'bar_value', }
- command_headers
-
Specifies default headers for particular commands.
command_headers => { SEND => { receipt => 'auto', }, SUBSCRIBE => { durable => 'true', ack => 'client', }, }
- body_encoder => $cb->( $body [, $content_type ] )
-
Specifies the encode function for the body of the frame. The function accepts two arguments: the body and the content type of the body if it specified in the frame. The function must return the encoded body.
body_encoder => sub { return encode_json( $_[0] ); }
- body_decoder => $cb->( $body [, $content_type ] )
-
Specifies the decode function for the body of the frame. The function accepts two arguments: the body and the content type of the body if it specified in the frame. The function must return the decoded body.
body_decoder => sub { return decode_json( $_[0] ); }
- on_connect => $cb->()
-
The
on_connect
callback is called when the connection is successfully established.Not set by default.
- on_disconnect => $cb->()
-
The
on_disconnect
callback is called when the connection is closed by any reason.Not set by default.
- on_error => $cb->( $err )
-
The
on_error
callback is called when occurred an error, which was affected on entire client (e. g. connection error or authentication error). Also theon_error
callback is called on command errors if the command callback is not specified. If theon_error
callback is not specified, the client just print an error messages toSTDERR
.
COMMAND METHODS
To execute the STOMP command you must call appropriate method. STOMP headers can be specified as command parameters. The client automatically adds content-length
header to all outgoing frames. Every command method can also accept two additional parameters: the body
parameter where you can specify the body of the frame, and the on_receipt
parameter that is the alternative way to specify the command callback.
If you want to receive RECEIPT
frame, you must specify receipt
header. The receipt
header can take the special value auto
. If it set, the receipt identificator will be generated automatically by the client. The RECEIPT
frame is passed to the command callback in first argument as the object of the class AnyEvent::Stomper::Frame. If the receipt
header is not specified the first argument of the command callback will be undef
.
For commands SUBSCRIBE
, UNSUBSCRIBE
, DISCONNECT
the client automatically adds receipt
header for internal usage.
The command callback is called in one of two cases depending on the presence of the receipt
header: when the command was successfully sent to the server or when the RECEIPT
frame will be received. If any error occurred during the command execution, the error object is passed to the callback in second argument. Error object is the instance of the class AnyEvent::Stomper::Error.
The command callback is optional. If it is not specified and any error occurred, the on_error
callback of the client is called.
The full list of all available headers for every command you can find in STOMP protocol specification and in documentation on your STOMP server. For various versions of STOMP protocol and various STOMP servers they can be differ.
send( [ %params ] [, $cb->( $receipt, $err ) ] )
Sends a message to a destination in the messaging system.
$stomper->send(
destination => '/queue/foo',
body => 'Hello, world!',
);
$stomper->send(
destination => '/queue/foo',
body => 'Hello, world!',
sub {
my $err = $_[1];
if ( defined $err ) {
my $err_msg = $err->message;
my $err_code = $err->code;
my $err_frame = $err->frame;
# error handling...
return;
}
}
);
$stomper->send(
destination => '/queue/foo',
receipt => 'auto',
body => 'Hello, world!',
on_receipt => sub {
my $receipt = shift;
my $err = shift;
if ( defined $err ) {
my $err_msg = $err->message;
my $err_code = $err->code;
my $err_frame = $err->frame;
# error handling...
return;
}
# receipt handling...
}
);
subscribe( [ %params ] [, $cb->( $msg ) ] )
The method is used to register to listen to a given destination. The subscribe
method require the on_message
callback, which is called on every received MESSAGE
frame from the server. The MESSAGE
frame is passed to the on_message
callback in first argument as the object of the class AnyEvent::Stomper::Frame. If the subscribe
method is called with one callback, this callback will be act as on_message
callback.
$stomper->subscribe(
id => 'foo',
destination => '/queue/foo',
sub {
my $msg = shift;
my $headers = $msg->headers;
my $body = $msg->body;
# message handling...
},
);
$stomper->subscribe(
id => 'foo',
destination => '/queue/foo',
ack => 'client',
on_receipt => sub {
my $receipt = shift;
my $err = shift;
if ( defined $err ) {
my $err_msg = $err->message;
my $err_code = $err->code;
my $err_frame = $err->frame;
return;
}
# receipt handling...
},
on_message => sub {
my $msg = shift;
my $headers = $msg->headers;
my $body = $msg->body;
# message handling...
}
);
unsubscribe( [ %params ] [, $cb->( $receipt, $err ) ] )
The method is used to remove an existing subscription.
$stomper->unsubscribe(
id => 'foo',
destination => '/queue/foo',
sub {
my $receipt = shift;
my $err = shift;
if ( defined $err ) {
my $err_msg = $err->message;
my $err_code = $err->code;
my $err_frame = $err->frame;
return;
}
# receipt handling...
}
);
ack( [ %params ] [, $cb->( $receipt, $err ) ] )
The method is used to acknowledge consumption of a message from a subscription using client
or client-individual
acknowledgment. Any messages received from such a subscription will not be considered to have been consumed until the message has been acknowledged via an ack()
method.
$stomper->ack( id => $ack_id );
$stomper->ack(
id => $ack_id,
receipt => 'auto',
sub {
my $receipt = shift;
my $err = shift;
if ( defined $err ) {
my $err_msg = $err->message;
my $err_code = $err->code;
my $err_frame = $err->frame;
# error handling...
}
# receipt handling...
}
);
nack( [ %params ] [, $cb->( $receipt, $err ) ] )
The nack
method is the opposite of ack
method. It is used to tell the server that the client did not consume the message.
$stomper->nack( id => $ack_id );
$stomper->nack(
id => $ack_id,
receipt => 'auto',
sub {
my $receipt = shift;
my $err = shift;
if ( defined $err ) {
my $err_msg = $err->message;
my $err_code = $err->code;
my $err_frame = $err->frame;
# error handling...
}
# receipt handling...
}
);
begin( [ %params ] [, $cb->( $receipt, $err ) ] )
The method begin
is used to start a transaction.
commit( [ %params ] [, $cb->( $receipt, $err ) ] )
The method commit
is used to commit a transaction.
abort([ %params ] [, $cb->( $receipt, $err ) ] )
The method abort
is used to roll back a transaction.
disconnect( [ %params ] [, $cb->( $receipt, $err ) ] )
A client can disconnect from the server at anytime by closing the socket but there is no guarantee that the previously sent frames have been received by the server. To do a graceful shutdown, where the client is assured that all previous frames have been received by the server, you must call disconnect
method and wait for the RECEIPT
frame.
execute( $command, [ %params ] [, $cb->( $receipt, $err ) ] )
An alternative method to execute commands. In some cases it can be more convenient.
$stomper->execute( 'SEND',
destination => '/queue/foo',
receipt => 'auto',
body => 'Hello, world!',
sub {
my $receipt = shift;
my $err = shift;
if ( defined $err ) {
my $err_msg = $err->message;
my $err_code = $err->code;
my $err_frame = $err->frame;
# error handling...
return;
}
# receipt handling...
}
);
ERROR CODES
Every error object, passed to callback, contain error code, which can be used for programmatic handling of errors. AnyEvent::Stomper provides constants for error codes. They can be imported and used in expressions.
use AnyEvent::Stomper qw( :err_codes );
- E_CANT_CONN
-
Can't connect to the server. All operations were aborted.
- E_IO
-
Input/Output operation error. The connection to the STOMP server was closed and all operations were aborted.
- E_CONN_CLOSED_BY_REMOTE_HOST
-
The connection closed by remote host. All operations were aborted.
- E_CONN_CLOSED_BY_CLIENT
-
Connection closed by client prematurely. Uncompleted operations were aborted
- E_OPRN_ERROR
-
Operation error. For example, missing required header.
- E_UNEXPECTED_DATA
-
The client received unexpected data from the server. The connection to the STOMP server was closed and all operations were aborted.
- E_READ_TIMEDOUT
-
Read timed out. The connection to the STOMP server was closed and all operations were aborted.
OTHER METHODS
host()
Gets current host of the client.
port()
Gets current port of the client.
connection_timeout( [ $fractional_seconds ] )
Gets or sets the connection_timeout
of the client. The undef
value resets the connection_timeout
to default value.
reconnect_interval( [ $fractional_seconds ] )
Gets or sets reconnect_interval
of the client.
on_connect( [ $callback ] )
Gets or sets the on_connect
callback.
on_disconnect( [ $callback ] )
Gets or sets the on_disconnect
callback.
on_error( [ $callback ] )
Gets or sets the on_error
callback.
force_disconnect()
The method for forced disconnection. All uncompleted operations will be aborted.
WORKING WITH CLUSTER
If you have the cluster of STOMP servers, you can use AnyEvent::Stomper::Cluster to work with it.
SEE ALSO
AUTHOR
Eugene Ponizovsky, <ponizovsky@gmail.com>
Sponsored by SMS Online, <dev.opensource@sms-online.com>
COPYRIGHT AND LICENSE
Copyright (c) 2016, Eugene Ponizovsky, SMS Online. All rights reserved.
This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.