JSON-RPC/XML-RPC Server for Rack Applications

This is a Rack middleware that facilitates the creation of protocol-agnostic RPC servers. The current implementation provides support for JSON-RPC 2.0 and XML-RPC.

• https://github.com/datagraph/rack-rpc

Features

• Handles JSON-RPC and XML-RPC requests with the same code.
• Compatible with any Rack application and any Rack-based framework.
• Provides Rails-style controller filtering for your RPC methods.

Examples

A basic RPC server

require 'rack/rpc'

class Server < Rack::RPC::Server
  def hello_world
    "Hello, world!"
  end
  rpc 'hello_world' => :hello_world
end

Simple filtering

require 'rack/rpc'

class Server < Rack::RPC::Server
  before_filter :check_auth

  def hello_world
    "Hello, world!"
  end
  rpc 'hello_world' => :hello_world

  private

  def check_auth
    raise "Not authorized" unless authorized
  end
end

Filtering via a proc with more options

require 'rack/rpc'

class Server < Rack::RPC::Server
  before_filter :check_auth, :only => :super_secret_hello_world do
    raise "Not authorized" unless authorized
  end

  def hello_world
    "Hello, world!"
  end
  rpc 'hello_world' => :hello_world

  def super_secret_hello_world
    'super_secret_hello_world'
  end
  rpc 'super_secret_hello_world' => :super_secret_hello_world
end

Running the server

# config.ru
use Rack::RPC::Endpoint, Server.new

run MyApplication

Customizing the default RPC path

# config.ru
use Rack::RPC::Endpoint, Server.new, :path => '/api'

run MyApplication

More on Filters

The :only and :except options for filters can take a single method or an array of methods.

You can halt execution in a filter by raising an exception. An error response will be returned with the exception's message set as the error object's message text.

Communicationg with the Server

By default, methods will only be invoked on POST requests to "/rpc". The default path can be overridden by sending a :path option when creating your middleware (see example above).

The protocol used is determined by the CONTENT_TYPE header ("application/xml" and "text/xml" for XML and "application/json" for JSON).

Dependencies

• Rack (>= 1.0.0)
• Builder (>= 2.1.2)

Installation

The recommended installation method is via RubyGems. To install the latest official release of the gem, do:

% [sudo] gem install rack-rpc

Download

To get a local working copy of the development repository, do:

% git clone git://github.com/datagraph/rack-rpc.git

Alternatively, download the latest development version as a tarball as follows:

% wget http://github.com/datagraph/rack-rpc/tarball/master

Mailing List

• http://groups.google.com/group/rack-devel

Authors

• Arto Bendiken - http://ar.to/
• Josh Huckabee - http://joshhuckabee.com/

License

This is free and unencumbered public domain software. For more information, see http://unlicense.org/ or the accompanying {file:UNLICENSE} file.