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= Action Web Service -- Serving APIs on rails Action Web 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 Web 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 ActionWebService::API::Base derivative, and then specify this API definition class wherever you want to use that API. The implementation of the methods is done separately from the API specification. ==== Method name inflection Action Web 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 ActionWebService::API::Base +inflect_names+ option. ==== Inflection examples :add => Add :find_all => FindAll ==== Disabling inflection class PersonAPI < ActionWebService::API::Base inflect_names false end ==== API definition example class PersonAPI < ActionWebService::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 web_service_api PersonAPI def add end def remove end end == Publishing your APIs Action Web 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, public controller instance methods implement the API methods, and parameters are passed through to the methods in accordance with the API specification. The return value of the method 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 method and send back the wrapped return value. <em>This action must not be overridden.</em> ==== Direct dispatching example class PersonController < ApplicationController web_service_api PersonAPI def add end def remove end end class PersonAPI < ActionWebService::API::Base ... end For this example, protocol requests for +Add+ and +Remove+ methods sent to <tt>/person/api</tt> will be routed to the controller methods +add+ and +remove+. === Delegated dispatching This mode can be turned on by setting the +web_service_dispatching_mode+ option in a controller to <tt>:delegated</tt>. In this mode, the controller contains one or more web service objects (objects that implement an ActionWebService::API::Base definition). These web service objects are each mapped onto one controller action only. ==== Delegated dispatching example class ApiController < ApplicationController web_service_dispatching_mode :delegated web_service :person, PersonService.new end class PersonService < ActionWebService::Base web_service_api PersonAPI def add end def remove end end class PersonAPI < ActionWebService::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 +web_service+ method is called. <em>This action must not be overridden.</em> Other controller actions (actions that aren't the target of a +web_service+ call) are ignored for ActionWebService purposes, and can do normal action tasks. === Layered dispatching This mode can be turned on by setting the +web_service_dispatching_mode+ option in a controller to <tt>:layered</tt>. This mode is similar to _delegated_ mode, in that multiple web service objects can be attached to one controller, however, all protocol requests are sent to a single endpoint. Use this mode when you want to share code between XML-RPC and SOAP clients, for APIs where the XML-RPC method names have prefixes. An example of such a method name would be <tt>blogger.newPost</tt>. ==== Layered dispatching example class ApiController < ApplicationController web_service_dispatching_mode :layered web_service :mt, MovableTypeService.new web_service :blogger, BloggerService.new web_service :metaWeblog, MetaWeblogService.new end class MovableTypeService < ActionWebService::Base ... end class BloggerService < ActionWebService::Base ... end class MetaWeblogService < ActionWebService::API::Base ... end For this example, an XML-RPC call for a method with a name like <tt>mt.getCategories</tt> will be sent to the <tt>getCategories</tt> method on the <tt>:mt</tt> service. == Customizing WSDL generation You can customize the names used for the SOAP bindings in the generated WSDL by using the wsdl_service_name option in a controller: class WsController < ApplicationController wsdl_service_name 'MyApp' end You can also customize the namespace used in the generated WSDL for custom types and message definition types: class WsController < ApplicationController wsdl_namespace 'http://my.company.com/app/wsapi' end The default namespace used is 'urn:ActionWebService', if you don't supply one. == ActionWebService and UTF-8 If you're going to be sending back strings containing non-ASCII UTF-8 characters using the <tt>:string</tt> data type, you need to make sure that Ruby is using UTF-8 as the default encoding for its strings. The default in Ruby is to use US-ASCII encoding for strings, which causes a string validation check in the Ruby SOAP library to fail and your string to be sent back as a Base-64 value, which may confuse clients that expected strings because of the WSDL. Two ways of setting the default string encoding are: * Start Ruby using the <tt>-Ku</tt> command-line option to the Ruby executable * Set the <tt>$KCODE</tt> flag in <tt>config/environment.rb</tt> to the string <tt>'UTF8'</tt> == Testing your APIs === Functional testing You can perform testing of your APIs by creating a functional test for the controller dispatching the API, and calling #invoke in the test case to perform the invocation. Example: class PersonApiControllerTest < Test::Unit::TestCase def setup @controller = PersonController.new @request = ActionController::TestRequest.new @response = ActionController::TestResponse.new end def test_add result = invoke :remove, 1 assert_equal true, result end end This example invokes the API method <tt>test</tt>, defined on the PersonController, and returns the result. If you're not using SOAP (or you're having serialisation difficulties), you can test XMLRPC like this: class PersonApiControllerTest < Test::Unit::TestCase def setup @controller = PersonController.new @request = ActionController::TestRequest.new @response = ActionController::TestResponse.new @protocol = :xmlrpc # can also be :soap, the default end def test_add result = invoke :remove, 1 # no change here assert_equal true, result end end === Scaffolding You can also test your APIs with a web browser by attaching scaffolding to the controller. Example: class PersonController web_service_scaffold :invocation end This creates an action named <tt>invocation</tt> on the PersonController. Navigating to this action lets you select the method to invoke, supply the parameters, and view the result of the invocation. == Using the client support Action Web 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 Web 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 Web Service client support can only be guaranteed to work with a subset. ==== Factory created client example class BlogManagerController < ApplicationController web_client_api :blogger, :xmlrpc, 'http://url/to/blog/api/RPC2', :handler_name => 'blogger' end class SearchingController < ApplicationController web_client_api :google, :soap, 'http://url/to/blog/api/beta', :service_name => 'GoogleSearch' end See ActionWebService::API::ActionController::ClassMethods for more details. ==== Manually created client example class PersonAPI < ActionWebService::API::Base api_method :find_all, :returns => [[Person]] end soap_client = ActionWebService::Client::Soap.new(PersonAPI, "http://...") persons = soap_client.find_all class BloggerAPI < ActionWebService::API::Base inflect_names false api_method :getRecentPosts, :returns => [[Blog::Post]] end blog = ActionWebService::Client::XmlRpc.new(BloggerAPI, "http://.../xmlrpc", :handler_name => "blogger") posts = blog.getRecentPosts See ActionWebService::Client::Soap and ActionWebService::Client::XmlRpc for more details. == Dependencies Action Web 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 Web Service version can be downloaded from http://rubyforge.org/projects/actionservice == Installation You can install Action Web Service with the following command. % [sudo] ruby setup.rb == License Action Web Service is released under the MIT license. == Support The Ruby on Rails mailing list Or, to contact the author, send mail to firstname.lastname@example.org