= Action Service -- Serving APIs on rails

Action Service provides a way to publish interoperable web service APIs with
Rails without spending a lot of time delving into protocol details.


== Features

* SOAP RPC protocol support
* Dynamic WSDL generation for APIs
* XML-RPC protocol support
* Clients that use the same API definitions as the server for
  easy interoperability with other Action Service based applications
* Type signature hints to improve interoperability with static languages
* Active Record model class support in signatures


== Defining your APIs

You specify the methods you want to make available as API methods in an
ActionService::API::Base derivative, and then specify this API
definition class wherever you want to use that API. 

The implementation of the methods is done seperately to the API
specification.


==== Method name inflection

Action Service will camelcase the method names according to Rails Inflector
rules for the API visible to public callers. What this means, for example
is that the method names in generated WSDL will be camelcased, and callers will
have to supply the camelcased name in their requests for the request to
succeed.

If you do not desire this behaviour, you can turn it off with the
ActionService::API::Base +inflect_names+ option.


==== Inflection examples

  :add       => Add
  :find_all  => FindAll

  
==== Disabling inflection

  class PersonAPI < ActionService::API::Base
    inflect_names false
  end


==== API definition example

  class PersonAPI < ActionService::API::Base
    api_method :add, :expects => [:string, :string, :bool], :returns => [:int]
    api_method :remove, :expects => [:int], :returns => [:bool]
  end

==== API usage example

  class PersonController < ActionController::Base
    service_api PersonAPI

    def add
    end

    def remove
    end
  end


== Publishing your APIs

Action Service uses Action Pack to process protocol requests.  There are two
modes of dispatching protocol requests, _Direct_, and _Delegated_.


=== Direct dispatching

This is the default mode. In this mode, controller actions implement the API
methods, and parameters for incoming method calls will be placed in
<tt>@params</tt> (keyed by name), and <tt>@method_params</tt> (ordered list).

The return value of the action is sent back as the return value to the
caller.

In this mode, a special <tt>api</tt> action is generated in the target
controller to unwrap the protocol request, forward it on to the relevant action
and send back the wrapped return value. <em>This action must not be
overridden.</em>

==== Direct dispatching example

  class PersonController < ApplicationController
    service_api PersonAPI

    def add
    end

    def remove
    end
  end

  class PersonAPI < ActionService::API::Base
    ...
  end


For this example, protocol requests for +Add+ and +Remove+ methods sent to
<tt>/person/api</tt> will be routed to the actions +add+ and +remove+.


=== Delegated dispatching

This mode can be turned on by setting the +service_dispatching_mode+ option
in a controller.

In this mode, the controller contains one or more service API objects (objects
that implement an ActionService::API::Base definition). These API
objects are each mapped onto one controller action only.

==== Delegated dispatching example

  class ApiController < ApplicationController
    service_dispatching_mode :delegated

    service :person, PersonService.new
  end

  class PersonService < ActionService::Base
    service_api PersonAPI

    def add
    end

    def remove
    end
  end

  class PersonAPI < ActionService::API::Base
    ...
  end


For this example, all protocol requests for +PersonService+ are
sent to the <tt>/api/person</tt> action.

The <tt>/api/person</tt> action is generated when the +service+
method is called. <em>This action must not be overridden.</em>

Other controller actions (actions that aren't the target of a +service+ call)
are ignored for ActionService purposes, and can do normal action tasks.


== Using the client support

Action Service includes client classes that can use the same API
definition as the server. The advantage of this approach is that your client
will have the same support for Active Record and structured types as the
server, and can just use them directly, and rely on the marshaling to Do The
Right Thing.

*Note*: The client support is intended for communication between Ruby on Rails
applications that both use Action Service. It may work with other servers, but
that is not its intended use, and interoperability can't be guaranteed, especially
not for .NET web services. 

Web services protocol specifications are complex, and Action Service can only
be guaranteed to work with a subset.

If you have the need for clients for a complex service not running on Action
Service, it is recommended that you use +wsdl2ruby+ and generate the client
stub classes.

==== Factory created client example

  class BlogManagerController < ApplicationController
    client_api :blogger, :xmlrpc, 'http://url/to/blog/api/RPC2', :handler_name => 'blogger'
  end

  class SearchingController < ApplicationController
    client_api :google, :soap, 'http://url/to/blog/api/beta', :service_name => 'GoogleSearch'
  end

See ActionService::API::ActionController::ClassMethods for more details.

==== Manually created client example

  class PersonAPI < ActionService::API::Base
    api_method :find_all, :returns => [[Person]]
  end

  soap_client = ActionService::Client::Soap.new(PersonAPI, "http://...")
  persons = soap_client.find_all

  class BloggerAPI < ActionService::API::Base
    inflect_names false
    api_method :getRecentPosts, :returns => [[Blog::Post]]
  end

  blog = ActionService::Client::XmlRpc.new(BloggerAPI, "http://.../xmlrpc", :handler_name => "blogger")
  posts = blog.getRecentPosts


See ActionService::Client::Soap and ActionService::Client::XmlRpc for more details.

== Dependencies

Action Service requires that the Action Pack and Active Record are either
available to be required immediately or are accessible as GEMs.

It also requires a version of Ruby that includes SOAP support in the standard
library. At least version 1.8.2 final (2004-12-25) of Ruby is recommended, this
is the version tested against.


== Download

The latest Action Service version can be downloaded from
http://rubyforge.org/projects/actionservice


== Installation

You can install Action Service with the following command.

  % [sudo] ruby setup.rb


== License

Action Service is released under the MIT license.


== Support

The Ruby on Rails mailing list

Or, to contact the author, send mail to bitserf@gmail.com