Catalyst-Plugin-Server-JSONRPC

NAME

Catalyst::Plugin::Server::JSONRPC -- Catalyst JSONRPC Server Plugin

SYNOPSIS

        package MyApp;
        use Catalyst qw/Server Server::JSONRPC/;

        package MyApp::Controller::Example;
        use base 'Catalyst::Controller';

        sub echo : JSONRPC {                     # available as: example.echo
            my ( $self, $c, @args ) = @_;
            $c->stash->{jsonrpc} = join ', ', @args;
        }

        sub ping : JSONRPCPath('/ping') {        # available as: ping
            my ( $self, $c ) = @_;
            $c->stash->{jsonrpc} = 'Pong';
        }

        sub world : JSONRPCRegex(/hello/) {      # available as: hello
            my ($self, $c) = @_;
            $c->stash->{jsonrpc} = 'World';
        }

        sub echo : JSONRPCLocal {                # available as: example.echo
            my ( $self, $c, @args ) = @_;
            $c->stash->{jsonrpc} = join ', ', @args;
        }

        sub ping : JSONRPCGlobal {               # available as: ping
            my ( $self, $c ) = @_;
            $c->stash->{jsonrpc} = 'Pong';
        }

DESCRIPTION

JSONRPC Plugin for Catalyst which we tried to make compatible with the way Catalyst works with URLS. Main features are:

Split JSONRPC methodNames by STRING to find out Controller.
Single entrypoint for JSONRPC calls, like http://host.tld/rpc
DispatchTypes (attributes) which work much the same as Catalyst attrs
JSONRPC Parameter handling transparent to Catalyst parameter handling

HOW IT WORKS

The default behaviour will handle JSONRPC Requests sent to "/rpc" by creating an OBJECT containing JSONRPC specific parameters in "$c->req->jsonrpc".

Directly after, it will find out the Path of the Action to dispatch to, by splitting methodName by ".":

      methodName: hello.world
      path      : /hello/world

From this point, it will dispatch to '/hello/world' when it exists, like Catalyst Urls would do. What means: you will be able to set Regexes, Paths etc on subroutines to define the endpoint.

We discuss these custom JSONRPC attributes below.

When the request is dispatched, we will return $c->stash->{jsonrpc} to the jsonrpc client, or, when it is not available, it will return $c->stash to the client. There is also a way of defining $c->stash keys to be send back to the client.

ATTRIBUTES

You can mark any method in your Catalyst application as being available remotely by using one of the following attributes, which can be added to any existing attributes, except Private. Remember that one of the mentioned attributes below are automatically also Privates...

JSONRPC

        Make this method accessible via JSONRPC, the same way as Local does
        when using catalyst by URL.

        The following example will be accessible by method "hello.world":

          package Catalyst::Controller::Hello
          sub world : JSONRPC {}

JSONRPCLocal

Identical version of attribute "JSONRPC"

JSONRPCGlobal

        Make this method accessible via JSONRPC, the same way as GLOBAL does
        when using catalyst by URL.

        The following example will be accessible by method "ping":

          package Catalyst::Controller::Hello
          sub ping : JSONRPCGlobal {}

JSONRPCPath('/say/hello')

        Make this method accessible via JSONRPC, the same way as Path does
        when using catalyst by URL.

        The following example will be accessible by method "say.hello":

          package Catalyst::Controller::Hello
          sub hello : JSONRPCPath('/say/hello') {}

JSONRPCRegex('foo')

        Make this method accessible via JSONRPC, the same way as Regex does
        when using catalyst by URL.

        The following example will be accessible by example methods:
        "a.foo.method" "wedoofoohere" "foo.getaround"

          package Catalyst::Controller::Hello
          sub hello : JSONRPCPath('foo') {}

ACCESSORS

Once you've used the plugin, you'll have an $c->request->jsonrpc accessor which will return an "Catalyst::Plugin::Server::JSONRPC" object.

You can query this object as follows:

$c->req->jsonrpc->is_jsonrpc_request

        Boolean indicating whether the current request has been initiated
        via JSONRPC

$c->req->jsonrpc->config

        Returns a "Catalyst::Plugin::Server::JSONRPC::Config" object. See
        the "CONFIGURATION" below on how to use and configure it.

$c->req->jsonrpc->body

The body of the original JSONRPC call

$c->req->jsonrpc->method

The name of the original method called via JSONRPC

$c->req->jsonrpc->args

A list of parameters supplied by the JSONRPC call

$c->req->jsonrpc->result_as_string

The JSON body that will be sent back to the JSONRPC client

$c->req->jsonrpc->error

Allows you to set jsonrpc fault code and message

Server Accessors

The following accessors are always available, whether you're in a jsonrpc specific request or not

$c->server->jsonrpc->list_methods

        Returns a HASHREF containing the available jsonrpc methods in
        Catalyst as a key, and the "Catalyst::Action" object as a value.

CATALYST REQUEST

To make things transparent, we try to put JSONRPC params into the Request object of Catalyst. But first we will explain something about the JSONRPC specifications.

A full draft of these specifications can be found on: "http://www.jsonrpc.com/spec"

In short, a jsonrpc-request consists of a methodName, like a subroutine name, and a list of parameters. This list of parameters may contain strings (STRING), arrays (LIST) and structs (HASH). Off course, these can be nested.

$c->req->arguments

        We will put the list of arguments into $c->req->arguments, thisway
        you can fetch this list within your dispatched-to-subroutine:

          sub echo : JSONRPC {
              my ($self, $c, @args) = @_;
              $c->log->debug($arg[0]);              # Prints first JSONRPC parameter
                                                    # to debug log
          }

$c->req->parameters

        Because JSONRPC parameters are a LIST, we can't just fill
        $c->req->paremeters. To keep things transparent, we made an extra
        config option what tells the JSONRPC server we can assume the
        following conditions on all JSONRPC requests: - There is only one
        JSONRPC parameter - This JSONRPC parameter is a struct (HASH)

        We will put this STRUCT as key-value pairs into $c->req->parameters.

$c->req->params

Alias of $c->req->parameters

$c->req->param

Alias of $c->req->parameters

INTERNAL JSONRPC FUNCTIONS

The following system functions are available to the public.,

system.listMethods

returns a list of available RPC methods.

DEFINING RETURN VALUES

The JSON-RPC response must contain a single parameter, which may contain an array (LIST), struct (HASH) or a string (STRING). To define the return values in your subroutine, you can alter $c->stash in three different ways.

Defining $c->stash->{jsonrpc}
When defining $c->stash->{jsonrpc}, the JSONRPC server will return these values to the client.

When there is no $c->stash->{jsonrpc} When there is no "$c->stash->{jsonrpc}" set, it will return the complete "$c->stash"

CONFIGURATION

The JSONRPC Plugin accepts the following configuration options, which can be set in the standard Catalyst way (See "perldoc Catalyst" for details):

Your::App->config( jsonrpc => { key => value } );

You can look up any of the config parameters this package uses at runtime by calling:

$c->server->jsonrpc->config->KEY

path

        This specifies the entry point for your jsonrpc server; all requests
        are dispatched from there. This is the url any JSONRCP client should
        post to. You can change this to any "Regex" wish.

        The default is: "qr!^(/?)rpc(/|$)!i", which matches on a top-level
        path begining with "rpc" preceeded or followed by an optional "/",
        like this:

            http://your-host.tld/rpc

prefix

This specifies the prefix of the forward url.

        For example, with a prefix of "rpc", and a method "foo", the forward
        path would be come "/rpc/foo".

        The default is '' (empty).

separator

        This is a STRING used to split your method on, allowing you to use a
        hierarchy in your method calls.

        For example, with a separator of "." the method call "demo.echo"
        would be forwarded to "/demo/echo". To make "demo_echo" forward to
        the same path, you would change the separator to "_",

        The default is ".", splitting methods on a single "."

convert_params

        Make the arguments in "$c->req->jsonrpc->params" available as
        "$c->req->params".

        Defaults to true.

show_errors

        Make system errors in "$c->error" public to the rpc-caller in a
        JSON-RPC faultString. When show_errors is false, and your catalyst
        app generates a fault, it will return an JSON-RPC fault containing
        error number 500 and error string: "Internal Server Error".

        Defaults to false.

DIAGNOSTICS

Invalid JSONRPC request: No such method

        There is no corresponding method in your application that can be
        forwarded to.

Invalid JSONRPC request %s

There was an error parsing the JSONRPC request

Invalid JSONRPC request: Unknown error

An unexpected error occurred

TODO

Make error messages configurable/filterable

        Right now, whatever ends up on $c->error gets returned to the
        client. It would be nice to have a way to filter/massage these
        messages before they are sent back to the client.

Make stash filterable before returning

        Just like the error messages, it would be nice to be able to filter
        the stash before returning so you can filter out keys you don't want
        to return to the client, or just return a certain list of keys. This
        all to make transparent use of JSONRPC and web easier.

SEE ALSO

Catalyst::Manual, Catalyst::Request, Catalyst::Response, JSON::RPC::Common,

ACKNOWLEDGEMENTS

For the original implementation of this module:

Marcus Ramberg "mramberg@cpan.org" Christian Hansen Yoshinori Sano Jos Boumans (kane@cpan.org) Michiel Ootjers (michiel@cpan.org)

AUTHORS

Sergey Nosenko (darknos@cpan.org)

http://code.google.com/p/catalyst-server-jsonrpc

BUG REPORTS

Please submit all bugs regarding "Catalyst::Plugin::Server::JSONRPC" to http://code.google.com/p/catalyst-server-jsonrpc/issues/entry

LICENSE

This library is free software, you can redistribute it and/or modify it under the same terms as Perl itself.