1 package Catalyst::Engine::Stomp;
3 use List::MoreUtils qw/ uniq /;
6 use namespace::autoclean;
8 extends 'Catalyst::Engine::Embeddable';
10 our $VERSION = '0.05';
12 has connection => (is => 'rw', isa => 'Net::Stomp');
13 has conn_desc => (is => 'rw', isa => 'Str');
17 Catalyst::Engine::Stomp - write message handling apps with Catalyst.
24 $ENV{CATALYST_ENGINE} = 'Stomp';
25 require Catalyst::Engine::Stomp;
28 MyApp->config->{Engine::Stomp} =
30 hostname => '127.0.0.1',
35 # In a controller, or controller base class:
36 use base qw/ Catalyst::Controller::MessageDriven /;
38 # then create actions, which map as message types
39 sub testaction : Local {
42 # Reply with a minimal response message
43 my $response = { type => 'testaction_response' };
44 $c->stash->{response} = $response;
49 Write a Catalyst app connected to a Stomp messagebroker, not HTTP. You
50 need a controller that understands messaging, as well as this engine.
52 This is single-threaded and single process - you need to run multiple
53 instances of this engine to get concurrency, and configure your broker
54 to load-balance across multiple consumers of the same queue.
56 Controllers are mapped to Stomp queues, and a controller base class is
57 provided, Catalyst::Controller::MessageDriven, which implements
58 YAML-serialized messages, mapping a top-level YAML "type" key to
65 App entry point. Starts a loop listening for messages.
70 my ($self, $app, $oneshot) = @_;
72 die 'No Engine::Stomp configuration found'
73 unless ref $app->config->{'Engine::Stomp'} eq 'HASH';
75 # list the path namespaces that will be mapped as queues.
77 # this is known to use the deprecated
78 # Dispatcher->action_hash() method, but there doesn't appear
79 # to be another way to get the relevant strings out.
81 # http://github.com/rafl/catalyst-runtime/commit/5de163f4963d9dbb41d7311ca6f17314091b7af3#L2R644
87 values %{$app->dispatcher->action_hash};
90 my %template = %{$app->config->{'Engine::Stomp'}};
91 $self->connection(Net::Stomp->new(\%template));
92 $self->connection->connect();
93 $self->conn_desc($template{hostname}.':'.$template{port});
95 # subscribe, with client ack.
96 foreach my $queue (@queues) {
97 my $queue_name = "/queue/$queue";
98 $self->connection->subscribe({
99 destination => $queue_name,
106 my $frame = $self->connection->receive_frame();
107 $self->handle_stomp_frame($app, $frame);
108 last if $ENV{ENGINE_ONESHOT};
113 =head2 prepare_request
115 Overridden to add the source broker to the request, in place of the
120 sub prepare_request {
121 my ($self, $c, $req, $res_ref) = @_;
123 $self->next::method(@_);
124 $c->req->address($self->conn_desc);
127 =head2 finalize_headers
129 Overridden to dump out any errors encountered, since you won't get a
130 "debugging" message as for HTTP.
134 sub finalize_headers {
136 my $error = join "\n", @{$c->error};
138 $c->log->debug($error);
140 return $self->next::method($c);
143 =head2 handle_stomp_frame
145 Dispatch according to Stomp frame type.
149 sub handle_stomp_frame {
150 my ($self, $app, $frame) = @_;
152 my $command = $frame->command();
153 if ($command eq 'MESSAGE') {
154 $self->handle_stomp_message($app, $frame);
156 elsif ($command eq 'ERROR') {
157 $self->handle_stomp_error($app, $frame);
160 $app->log->debug("Got unknown Stomp command: $command");
164 =head2 handle_stomp_message
166 Dispatch a Stomp message into the Catalyst app.
170 sub handle_stomp_message {
171 my ($self, $app, $frame) = @_;
173 # queue -> controller
174 my $queue = $frame->headers->{destination};
175 my ($controller) = $queue =~ m|^/queue/(.*)$|;
178 my $config = $app->config->{'Engine::Stomp'};
179 my $url = 'stomp://'.$config->{hostname}.':'.$config->{port}.'/'.$controller;
180 my $req = HTTP::Request->new(POST => $url);
181 $req->content($frame->body);
182 $req->content_length(length $frame->body);
186 $app->handle_request($req, \$response);
188 # reply, if header set
189 if (my $reply_to = $response->headers->header('X-Reply-Address')) {
190 my $reply_queue = '/remote-temp-queue/' . $reply_to;
191 $self->connection->send({ destination => $reply_queue, body => $response->content });
194 # ack the message off the queue now we've replied / processed
195 $self->connection->ack( { frame => $frame } );
198 =head2 handle_stomp_error
200 Log any Stomp error frames we receive.
204 sub handle_stomp_error {
205 my ($self, $app, $frame) = @_;
207 my $error = $frame->headers->{message};
208 $app->log->debug("Got Stomp error: $error");
211 __PACKAGE__->meta->make_immutable;