1 package Catalyst::Engine::Stomp;
3 extends 'Catalyst::Engine::Embeddable';
7 use List::MoreUtils qw/ uniq /;
11 has connection => (is => 'rw', isa => 'Net::Stomp');
12 has conn_desc => (is => 'rw', isa => 'Str');
16 Catalyst::Engine::Stomp - write message handling apps with Catalyst.
23 $ENV{CATALYST_ENGINE} = 'Stomp';
24 require Catalyst::Engine::Stomp;
27 MyApp->config->{Engine::Stomp} =
29 hostname => '127.0.0.1',
34 # In a controller, or controller base class:
35 use base qw/ Catalyst::Controller::MessageDriven /;
37 # then create actions, which map as message types
38 sub testaction : Local {
41 # Reply with a minimal response message
42 my $response = { type => 'testaction_response' };
43 $c->stash->{response} = $response;
48 Write a Catalyst app connected to a Stomp messagebroker, not HTTP. You
49 need a controller that understands messaging, as well as this engine.
51 This is single-threaded and single process - you need to run multiple
52 instances of this engine to get concurrency, and configure your broker
53 to load-balance across multiple consumers of the same queue.
55 Controllers are mapped to Stomp queues, and a controller base class is
56 provided, Catalyst::Controller::MessageDriven, which implements
57 YAML-serialized messages, mapping a top-level YAML "type" key to
64 App entry point. Starts a loop listening for messages.
69 my ($self, $app, $oneshot) = @_;
71 die 'No Engine::Stomp configuration found'
72 unless ref $app->config->{'Engine::Stomp'} eq 'HASH';
74 # list the path namespaces that will be mapped as queues.
76 # this is known to use the deprecated
77 # Dispatcher->action_hash() method, but there doesn't appear
78 # to be another way to get the relevant strings out.
80 # http://github.com/rafl/catalyst-runtime/commit/5de163f4963d9dbb41d7311ca6f17314091b7af3#L2R644
86 values %{$app->dispatcher->action_hash};
89 my %template = %{$app->config->{'Engine::Stomp'}};
90 $self->connection(Net::Stomp->new(\%template));
91 $self->connection->connect();
92 $self->conn_desc($template{hostname}.':'.$template{port});
94 # subscribe, with client ack.
95 foreach my $queue (@queues) {
96 my $queue_name = "/queue/$queue";
97 $self->connection->subscribe({
98 destination => $queue_name,
105 my $frame = $self->connection->receive_frame();
106 $self->handle_stomp_frame($app, $frame);
107 last if $ENV{ENGINE_ONESHOT};
112 =head2 prepare_request
114 Overridden to add the source broker to the request, in place of the
119 sub prepare_request {
120 my ($self, $c, $req, $res_ref) = @_;
122 $self->next::method(@_);
123 $c->req->address($self->conn_desc);
126 =head2 finalize_headers
128 Overridden to dump out any errors encountered, since you won't get a
129 "debugging" message as for HTTP.
133 sub finalize_headers {
135 my $error = join "\n", @{$c->error};
137 $c->log->debug($error);
139 return $self->next::method($c);
142 =head2 handle_stomp_frame
144 Dispatch according to Stomp frame type.
148 sub handle_stomp_frame {
149 my ($self, $app, $frame) = @_;
151 my $command = $frame->command();
152 if ($command eq 'MESSAGE') {
153 $self->handle_stomp_message($app, $frame);
155 elsif ($command eq 'ERROR') {
156 $self->handle_stomp_error($app, $frame);
159 $app->log->debug("Got unknown Stomp command: $command");
163 =head2 handle_stomp_message
165 Dispatch a Stomp message into the Catalyst app.
169 sub handle_stomp_message {
170 my ($self, $app, $frame) = @_;
172 # queue -> controller
173 my $queue = $frame->headers->{destination};
174 my ($controller) = $queue =~ m!^/queue/(.*)$!;
177 my $config = $app->config->{'Engine::Stomp'};
178 my $url = 'stomp://'.$config->{hostname}.':'.$config->{port}.'/'.$controller;
179 my $req = HTTP::Request->new(POST => $url);
180 $req->content($frame->body);
181 $req->content_length(length $frame->body);
185 $app->handle_request($req, \$response);
187 # reply, if header set
188 if (my $reply_to = $response->headers->header('X-Reply-Address')) {
189 my $reply_queue = '/remote-temp-queue/' . $reply_to;
190 $self->connection->send({ destination => $reply_queue, body => $response->content });
193 # ack the message off the queue now we've replied / processed
194 $self->connection->ack( { frame => $frame } );
197 =head2 handle_stomp_error
199 Log any Stomp error frames we receive.
203 sub handle_stomp_error {
204 my ($self, $app, $frame) = @_;
206 my $error = $frame->headers->{message};
207 $app->log->debug("Got Stomp error: $error");
210 __PACKAGE__->meta->make_immutable;