File Coverage

blib/lib/Mojolicious/Plugin/Multiplex.pm

Criterion	Covered	Total	%
statement	20	20	100.0
branch	3	6	50.0
condition	1	3	33.3
subroutine	5	5	100.0
pod	1	1	100.0
total	30	35	85.7

line	stmt	bran	cond	sub	pod	time	code
1							package Mojolicious::Plugin::Multiplex;
2
3	1			1		711	use Mojo::Base 'Mojolicious::Plugin';
	1					2
	1					6
4
5							our $VERSION = '1.0';
6							$VERSION = eval $VERSION;
7
8	1			1		704	use Mojolicious::Plugin::Multiplex::Multiplexer;
	1					3
	1					9
9
10	1			1		424	use File::Share ();
	1					24518
	1					234
11
12							sub register {
13	1			1	1	56	my ($plugin, $app, $conf) = @_;
14
15	1					3	push @{ $app->static->paths }, File::Share::dist_dir('Mojolicious-Plugin-Multiplex');
	1					7
16
17							# this is still a gray area it seems, but certainly this will be honored even
18							# if in the future they add some new preferred type
19	1					269	my $types = $app->types;
20							$types->type(mjs => ['application/javascript'])
21	1	50				24	unless exists $types->mapping->{mjs};
22
23							$app->helper(multiplex => sub {
24	3			3		36052	my $c = shift;
25	3					12	my $tx = $c->tx;
26	3	50				21	return undef unless $tx->is_websocket;
27	3	50				24	$c->rendered(101) unless $tx->established;
28	3		33			818	return $c->stash->{'multiplex.multiplexer'} \|\|= Mojolicious::Plugin::Multiplex::Multiplexer->new(tx => $tx);
29	1					70	});
30							}
31
32							1;
33
34							=head1 NAME
35
36							Mojolicious::Plugin::Multiplex - A websocket multiplexing layer for Mojolicious applications
37
38							=head1 SYNOPSIS
39
40							use Mojolicious::Lite;
41
42							plugin 'Multiplex';
43
44							get '/' => 'index';
45
46							websocket '/multiplex' => sub {
47							my $c = shift;
48							my $multiplex = $c->multiplex;
49							$multiplex->on(subscribe => sub { ... });
50							$multiplex->on(message => sub { ... });
51							$multiplex->on(unsubscribe => sub { ... });
52							};
53
54							__DATA__
55
56							@@ index.html.ep
57
58							%= javascript 'websocket_multiplex.js';
59
67
68							=head1 DESCRIPTION
69
70							L implements a mechanism proposed by L for the multiplexing of data on a single websocket.
71							Rather than proposing both a protocol and a programmatic api to use it, they L a very simple protocol and reusing the api of the existing Javascript WebSocket api.
72							This has the immediate advantage (beyond having to dream up a client api) that existing front-end code that is written for a WebSocket can immediately use the multiplexer with no changes necessary.
73
74							Their proposal only includes a partially implemented reference implementation.
75							This module extends the protocol slightly in order to enough of the L<"WebSocket API"\|https://developer.mozilla.org/en-US/docs/Web/API/WebSocket> to be useful.
76							More extensions may be necessary if the API is to be completely implemented, however those last few details are rarely used and will likely not be missed.
77
78							On the server-side the logic is entirely up to the application author.
79							The module simply parses the multiplexed messages and emits events in accordance with them.
80							A typical use case may be to relay message to a bus, subscribing and unsubscribing from topics that it presents.
81							Another might be to stream updates to multiple types of data (perhaps in multiple parts of a single page application).
82							(Indeed those might not be distinct cases from each other).
83
84							For reference, the distribution comes with an example which uses L as a message broker for a multi-channel chat application.
85							The example may also be seen on L.
86
87							=head1 CAVEAT
88
89							While I'm declaring this module stable and production worthy, I still don't nearly have enough tests.
90							The biggest reason for this is that I don't have a great way to test Perl and Javascript together.
91							Unfortunately PhantomJS declared defeat right as L was catching on.
92							A project to wrap its successor, headless Chrome, is stalled waiting for now, so we wait.
93							Contributions from people with experience in this area would be greatly appreciated.
94
95							=head1 HELPERS
96
97							=head2 multiplex
98
99							my $multiplex = $c->multiplex;
100
101							Establishes the WebSocket connection (if it hasn't been already) and returns an instance of L.
102							The multiplexer is attached to the websocket stream and begins listening for messages.
103							The multiplexer emits events for incoming messages and has methods to send outgoing messages; more details about those are contained in its own documentation.
104
105							Note that for each websocket connection the same instance of the multiplexer will be returned on any subsequent call.
106							Though not prevented, the user is highly discouraged from sending other traffic over any websocket connection that is managed by a multiplexer.
107
108							=head1 BUNDLED FILES
109
110							=head2 websocket_multiplex.mjs
111
112
118
119							Bundled with this plugin is a javascript module file called C which contains the front-end code to create a multiplexer.
120							It exports the C class, whose constructor takes as its only argument an existing WebSocket object or a url string to build one.
121							This then is used to open new channel objects via the C method which takes a topic string as an arugment.
122							Topics can be almost any string, however they must not contain a comma (a limitation of the protocol).
123							The resulting channel objects implement the same API as a WebSocket (though they do not inherit from it).
124
125							The client-side multiplexer will also attempt to reconnect to closed sockets and when successful will automatically resubscribe to the channels that were subscribed.
126
127							N.B. This library is the least stable of the entire project.
128							Use with caution.
129
130							Also, this library will likely use very modern conventions, even going forward.
131							Older browsers are not the target for this file.
132							For those you want ...
133
134							=head2 websocket_multiplex.js
135
136
137
142
143							This is the above javascript module but transpiled back to work on older browsers (and minified).
144							It sets the global symbol C when loaded.
145							In all other ways it works just like the above file.
146
147							=head2 websocket_multiplex.js.map
148
149							A file used to get better diagnostics from the minified javascript file.
150
151							=head1 SOURCE REPOSITORY
152
153							L
154
155							=head1 AUTHOR
156
157							Joel Berger, Ejoel.a.berger@gmail.comE
158
159							=head1 ADDITIONAL THANKS
160
161							John Susek
162
163							=head1 COPYRIGHT AND LICENSE
164
165							Copyright (C) 2016-2018 by Joel Berger
166
167							This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
168
169							The multiplexer protocol and javascript code (both extended by this project) are copyright their original authors and by their nature are assumed to be in the public domain.
170
171							=cut
172
173