1JSON::RPC(3)          User Contributed Perl Documentation         JSON::RPC(3)
2
3
4

NAME

6       JSON::RPC - JSON RPC 2.0 Server Implementation
7

SYNOPSIS

9           # app.psgi
10           use strict;
11           use JSON::RPC::Dispatch;
12
13           my $dispatch = JSON::RPC::Dispatch->new(
14               prefix => "MyApp::JSONRPC::Handler",
15               router => Router::Simple->new( ... )
16           );
17
18           sub {
19               my $env = shift;
20               $dispatch->handle_psgi($env);
21           };
22

DESCRIPTION

24       JSON::RPC is a set of modules that implement JSON RPC 2.0 protocol.
25
26           If you are using old JSON::RPC code (up to 0.96), DO NOT EXPECT
27           YOUR CODE TO WORK WITH THIS VERSION. THIS VERSION IS
28           ****BACKWARDS INCOMPATIBLE****
29

BASIC USAGE

31       The JSON::RPC::Dispatch object is responsible for marshalling the
32       request.
33
34           my $dispatch = JSON::RPC::Dispatch->new(
35               router => ...,
36           );
37
38       The routing between the JSON RPC methods and their implementors are
39       handled by Router::Simple. For example, if you want to map method "foo"
40       to a "MyApp::JSONRPC::Handler" object instance's "handle_foo" method,
41       you specify something like the following in your router instance:
42
43           use Router::Simple::Declare;
44           my $router = router {
45               connect "foo" => {
46                   handler => "+MyApp::JSONRPC::Handler",
47                   action  => "handle_foo"
48               };
49           };
50
51           my $dispatch = JSON::RPC::Dispatch->new(
52               router => $router,
53           );
54
55       The "+" prefix in the handler classname denotes that it is already a
56       fully qualified classname. Without the prefix, the value of "prefix" in
57       the dispatch object will be used to qualify the classname. If you
58       specify it in your Dispatch instance, you may omit the prefix part to
59       save you some typing:
60
61           use JSON::RPC::Dispatch;
62           use Router::Simple::Declare;
63
64           my $router = router {
65               connect "foo" => {
66                   handler => "Foo",
67                   action  => "process",
68               };
69               connect "bar" => {
70                   handler => "Bar",
71                   action => "process"
72               }
73           };
74           my $dispatch = JSON::RPC::Dispatch->new(
75               prefix => "MyApp::JSONRPC::Handler",
76               router => $router,
77           );
78
79           # The above will roughly translate to the following:
80           #
81           # for method "foo"
82           #    my $handler = MyApp::JSONRPC::Handler::Foo->new;
83           #    $handler->process( ... );
84           #
85           # for method "bar"
86           #    my $handler = MyApp::JSONRPC::Handler::Bar->new;
87           #    $handler->process( ... );
88
89       The implementors are called handlers. Handlers are simple objects, and
90       will be instantiated automatically for you. Their return values are
91       converted to JSON objects automatically.
92
93       You may also choose to pass objects in the handler argument to connect
94       in  your router. This will save you the cost of instantiating the
95       handler object, and you also don't have to rely on us instantiating
96       your handler object.
97
98           use Router::Simple::Declare;
99           use MyApp::JSONRPC::Handler;
100
101           my $handler = MyApp::JSONRPC::Handler->new;
102           my $router = router {
103               connect "foo" => {
104                   handler => $handler,
105                   action  => "handle_foo"
106               };
107           };
108

HANDLERS

110       Your handlers are objects responsible for returning some sort of
111       reference structure that can be properly encoded via JSON/JSON::XS. The
112       handler only needs to implement the methods that you specified in your
113       router.
114
115       The handler methods will receive the following parameters:
116
117           sub your_handler_method {
118               my ($self, $params, $procedure, @extra_args) = @_;
119
120               return $some_structure;
121           }
122
123       In most cases you will only need the parameters. The exact format of
124       the $params is dependent on the caller -- you will be passed whatever
125       JSON structure that caller used to call your handler.
126
127       $procedure is an instance of JSON::RPC::Procedure. Use it if you need
128       to figure out more about the procedure.
129
130       @extra_args is optional, and will be filled with whatever extra
131       arguments you passed to handle_psgi(). For example,
132
133           # app.psgi
134           sub {
135               $dispatch->handle_psgi($env, "arg1", "arg2", "arg3");
136           }
137
138       will cause your handlers to receive the following arguments:
139
140           sub your_handler_method {
141               my ($self, $params, $procedure, $arg1, $arg2, $arg3) = @_;
142
143           }
144
145       This is convenient if you have application-specific data that needs to
146       be passed to your handlers.
147

EMBED IT IN YOUR WEBAPP

149       If you already have a web app (and whatever framework you might already
150       have), you may choose to embed JSON::RPC in your webapp instead of
151       directly calling it in your PSGI application.
152
153       For example, if you would like to your webapp's "rpc" handler to
154       marshall the JSON RPC request, you can do something like the following:
155
156           package MyApp;
157           use My::Favorite::WebApp;
158
159           sub rpc {
160               my ($self, $context) = @_;
161
162               my $dispatch =  ...; # grab it from somewhere
163               $dispatch->handle_psgi( $context->env );
164           }
165

ERRORS

167       When your handler dies, it is automatically included in the response
168       hash, unless no response was requested (see "NOTIFICATIONS").
169
170       For example, something like below
171
172           sub rpc {
173               ...
174               if ($bad_thing_happend) {
175                   die "Argh! I failed!";
176               }
177           }
178
179       Would result in a response like
180
181           {
182               error => {
183                   code => -32603,
184                   message => "Argh! I failed! at ...",
185               }
186           }
187
188       However, you can include custom data by die()'ing with a hash:
189
190           sub rpc {
191               ...
192               if ($bad_thing_happend) {
193                   die { message => "Argh! I failed!", data => time() };
194               }
195           }
196
197       This would result in:
198
199           {
200               error => {
201                   code => -32603,
202                   message => "Argh! I failed! at ...",
203                   data => 1339817722,
204               }
205           }
206

NOTIFICATIONS

208       Notifications are defined as procedures without an id.  Notification
209       handling does not produce a response. When all procedures are
210       notifications no content is returned (if the request is valid).  To
211       maintain some basic compatibility with relaxed client implementations,
212       JSON::RPC::Dispatch includes responses when procedures do not have a
213       "jsonrpc" field set to "2.0".
214
215       Note that no error is returned in response to a notification when the
216       handler dies or when the requested method is not available.
217
218       For example, a request structure like this:
219
220           [
221               {"jsonrpc": "2.0", "method": "sum", "params": [1,2,4], "id": "1"},
222               {"jsonrpc": "2.0", "method": "notify_hello", "params": [7]},
223               {"jsonrpc": "2.0", "method": "keep_alive"},
224               {"jsonrpc": "2.0", "method": "get_data", "id": "9"}
225           ]
226
227       Would result in a response like
228
229           [
230               {"jsonrpc": "2.0", "result": 7, "id": "1"},
231               {"jsonrpc": "2.0", "result": ["hello", 5], "id": "9"}
232           ]
233

BACKWARDS COMPATIBILITY

235       Eh, not compatible at all. JSON RPC 0.xx was fine, but it predates
236       PSGI, and things are just... different before and after PSGI.
237
238       Code at version 0.96 has been moved to JSON::RPC::Legacy namespace, so
239       change your application to use JSON::RPC::Legacy if you were using the
240       old version.
241

AUTHORS

243       Daisuke Maki
244
245       Shinichiro Aska
246
247       Yoshimitsu Torii
248

AUTHOR EMERITUS

250       Makamaka Hannyaharamitu, <makamaka[at]cpan.org> - JSON::RPC modules up
251       to 0.96
252
254       The JSON::RPC module is
255
256       Copyright (C) 2011 by Daisuke Maki
257
258       This library is free software; you can redistribute it and/or modify it
259       under the same terms as Perl itself, either Perl version 5.8.0 or, at
260       your option, any later version of Perl 5 you may have available.
261
262       See JSON::RPC::Legacy for copyrights and license for previous versions.
263
264
265
266perl v5.28.1                      2019-02-02                      JSON::RPC(3)
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