# 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](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 the `E_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](https://metacpan.org/pod/AnyEvent::Handle) parameters. handle_params => { autocork => 1, linger => 60, } Enabling of the `autocork` parameter can improve performance. See documentation on [AnyEvent::Handle](https://metacpan.org/pod/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', }, } - 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 the `on_error` callback is called on command errors if the command callback is not specified. If the `on_error` callback is not specified, the client just print an error messages to `STDERR`. # 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 identifier 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](https://metacpan.org/pod/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. First case, when the command was successfully written to the socket. Second case, when the `RECEIPT` frame will be received. In first case `on_receipt` callback can be called synchronously. 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](https://metacpan.org/pod/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](https://metacpan.org/pod/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. Method `ack()` must be called with required parameter `message` in which must be specified the `MESSAGE` frame. $stomper->ack( message => $msg ); $stomper->ack( message => $msg, 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. Method `nack()` must be called with required parameter `message` in which must be specified the `MESSAGE` frame. $stomper->nack( message => $msg ); $stomper->nack( message => $msg, 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](https://metacpan.org/pod/AnyEvent::Stomper::Cluster) to work with it. # SEE ALSO [AnyEvent::Stomper::Cluster](https://metacpan.org/pod/AnyEvent::Stomper::Cluster) # AUTHOR Eugene Ponizovsky, Sponsored by SMS Online, # COPYRIGHT AND LICENSE Copyright (c) 2016-2017, 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.