ActiveResource探究（一）－－跑起来再说

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ActiveResource探究一

 

本教程向大家展示使用ActiveResource创建简单的REST风格的API。包括两个嵌套得Model、认证和客户端。目的是快速地搭建一个可用的REST API。

 

步骤一：新建一个项目

rails ares-demo

使用rails 2.0.2版本，我想这与版本无关。

 

步骤二：安装两个好用的插件

 

Resource This插件会将默认rest风格的action加到controller上。并且支持多层资源嵌套...通过下面的命令安装：

script/plugin install http://jnewland.com/svn/public/ruby/rails/plugins/resource_this/

 

Restful Authentication众所周知是一个认证插件，通过下面的命令安装：

script/plugin install http://svn.techno-weenie.net/projects/plugins/restful_authentication/

 

步骤三：设置restful authentication

 

非常简单，使用生成器生成migrations还有其他一些东西，具体用法请搜索restful authentication的用法指导

./script/generate authenticated user sessions

 

步骤四：生成程序Model

 

接下来就是生成你的model了。我门做一个简单的，posts包括很多comments，posts和comments都属于user，命令如下：

./script/generate scaffold posts
./script/generate scaffold comments

下面修改migration文件，如下：

db/migrate/002_create_posts.rb

class CreatePosts < ActiveRecord::Migration
  def self.up
    create_table :posts do |t|
      t.column :content, :text
      t.column :user_id, :integer
      t.timestamps
    end
  end

  def self.down
    drop_table :posts
  end
end

db/migrate/003_create_comments.rb

class CreateComments < ActiveRecord::Migration
  def self.up
    create_table :comments do |t|
      t.column :content, :text
      t.column :user_id, :integer
      t.column :post_id, :integer
      t.timestamps
    end
  end

  def self.down
    drop_table :comments
  end
end

Next you'll need to add the relationships to your model classes. Add the following bit to the front of app/models/user.rb

下一步给这三个模型加上关联：

class User < ActiveRecord::Base
  # custom relationships
  has_many :posts
  has_many :comments

app/models/post.rb

class Post < ActiveRecord::Base
  belongs_to :user
  has_many :comments
end

and app/models/comment.rb

class Comment < ActiveRecord::Base
  belongs_to :user
  belongs_to :post
end

用下面命令生成数据库：

 

rake db:migrate

 

步骤五：装载测试数据

 

添加一些默认数据，执行命令script/console,如下：

>> u1 = User.new(:login => "test1", :email => "[email protected]", :password => "test1", :password_confirmation => "test1")
=> #
>> u1.save
=> true
>> u2 = User.new(:login => "test2", :email => "[email protected]", :password => "test2", :password_confirmation => "test2")
=> #
>> u2.save
=> true
>> p = Post.new(:user => u1, :content => "The first post")
=> #
>> p.save
=> true
>> c = Comment.new(:user => u2, :post => p, :content => "first!")
=> #
>> c.save
=> true
>>

 

步骤六：resource_this!

 

接下来我们用插件resource_this!修改如下文件app/controllers/posts_controller.rb

class PostsController < ApplicationController
  resource_this
end

app/controllers/comments_controller.rb

 

class CommentsController < ApplicationController
  resource_this :nested => [:post]
end

And finally update config/routes.rb

 

ActionController::Routing::Routes.draw do |map|
  map.resources :posts do |post|
    post.resources :comments
  end

  map.resources :users

  map.resource :session
end

就是这样，现在你可以关注你的API了！

 

步骤七：浏览

 

用命令script/server启动网站服务器，访问下面的链接

• http://localhost:3000/posts/1.xml
• http://localhost:3000/posts/1/comments.xml

 

步骤八：开船

 

到目前为止，我们的service对所有人开放。我们将加入简单的认证，我们将对某些action加以控制：

修改app/controllers/application.rb

class ApplicationController < ActionController::Base
  include AuthenticatedSystem
  before_filter :login_required, :only => [:create,:edit,:new,:update,:destroy]
  helper :all # include all helpers, all the time

  # See ActionController::RequestForgeryProtection for details
  # Uncomment the :secret if you're not using the cookie session store
  protect_from_forgery # :secret => 'b845cf981afbfef06600e5d7f23e0fed'
end

 

步骤九：客户端

 

我们可以通过curl或浏览器测试，但是ActiveResource真正的魅力是使用ruby对象测试。所以我们将创建一个简单的客户端api。在lib目录下建一个文件"ares_sample_client.rb"，并加入以下代码：

require 'activeresource'

module Sample
  module Client
    class API
      class Post < ActiveResource::Base
        self.site = "http://localhost:3000"
      end
      
      class Comment < ActiveResource::Base
        self.site = "http://localhost:3000"
      end
    end
  end
end

 

现在我们可以同两国console来测试我们的成果了，确保server启动在3000端口，并且启动console：script/console

          
>> require 'ares_sample_client.rb'
=> ["Sample"]
>> posts = Sample::Client::API::Post.find(:all)
=> [#Wed Jan 09 02:36:34 UTC 2008, "id"=>1, "content"=>"The first post", "user_id"=>1, "created_at"=>Wed Jan 09 02:36:34 UTC 2008}, @prefix_options={}>]
>> 

>> p = Sample::Client::API::Post.create
ActiveResource::UnauthorizedAccess: Failed with 401 Unauthorized
        from /usr/lib/ruby/gems/1.8/gems/activeresource-2.0.2/lib/active_resource/connection.rb:125:in `handle_response'
        from /usr/lib/ruby/gems/1.8/gems/activeresource-2.0.2/lib/active_resource/connection.rb:112:in `request'
        from /usr/lib/ruby/gems/1.8/gems/activeresource-2.0.2/lib/active_resource/connection.rb:101:in `post'
        from /usr/lib/ruby/gems/1.8/gems/activeresource-2.0.2/lib/active_resource/base.rb:803:in `create'
        from /usr/lib/ruby/gems/1.8/gems/activeresource-2.0.2/lib/active_resource/base.rb:636:in `save_without_validation'
        from /usr/lib/ruby/gems/1.8/gems/activeresource-2.0.2/lib/active_resource/validations.rb:262:in `save'
        from /usr/lib/ruby/gems/1.8/gems/activeresource-2.0.2/lib/active_resource/base.rb:339:in `create'
        from /usr/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/core_ext/object/misc.rb:28:in `returning'
        from /usr/lib/ruby/gems/1.8/gems/activeresource-2.0.2/lib/active_resource/base.rb:339:in `create'
        from (irb):3
>> 

 

我们的API成功了，认证系统也发挥作用了。我们没有通过认证，所有不能够创建post，那么现在我们就加入认证来测试一下：

module Sample
  module Client
    class API
      class Post < ActiveResource::Base
        self.site = "http://test1:test1@localhost:3000"
      end
      
      class Comment < ActiveResource::Base
        self.site = "http://test1:test1@localhost:3000"
      end
    end
  end
end

 

需要注意的是，认证应用在整个类...这是的api使用相当容易，但是使多个用户使用变困难了，不管如何，我们的程序起作用了，我们再看看：

>> p = Sample::Client::API::Post.create(:content => "Should succeed", :user_id => 1)
=> #Wed Jan 09 02:55:22 UTC 2008, "id"=>3, "content"=>"Should succeed", "user_id"=>1, "created_at"=>Wed Jan 09 02:55:22 UTC 2008}, @prefix_options={}>
>> p.save
=> true
>> 

 

非常好！

 

请继续阅读本教程的第二部分