require 'action_view' require 'action_controller' require 'action_controller/log_subscriber' module ActionController # API Controller is a lightweight version of ActionController::Base, # created for applications that don't require all functionalities that a complete # \Rails controller provides, allowing you to create controllers with just the # features that you need for API only applications. # # An API Controller is different from a normal controller in the sense that # by default it doesn't include a number of features that are usually required # by browser access only: layouts and templates rendering, cookies, sessions, # flash, assets, and so on. This makes the entire controller stack thinner, # suitable for API applications. It doesn't mean you won't have such # features if you need them: they're all available for you to include in # your application, they're just not part of the default API Controller stack. # # By default, only the ApplicationController in a \Rails application inherits # from ActionController::API. All other controllers in turn inherit # from ApplicationController. # # A sample controller could look like this: # # class PostsController < ApplicationController # def index # @posts = Post.all # render json: @posts # end # end # # Request, response and parameters objects all work the exact same way as # ActionController::Base. # # == Renders # # The default API Controller stack includes all renderers, which means you # can use render :json and brothers freely in your controllers. Keep # in mind that templates are not going to be rendered, so you need to ensure # your controller is calling either render or redirect in # all actions, otherwise it will return 204 No Content response. # # def show # @post = Post.find(params[:id]) # render json: @post # end # # == Redirects # # Redirects are used to move from one action to another. You can use the # redirect method in your controllers in the same way as # ActionController::Base. For example: # # def create # redirect_to root_url and return if not_authorized? # # do stuff here # end # # == Adding new behavior # # In some scenarios you may want to add back some functionality provided by # ActionController::Base that is not present by default in # ActionController::API, for instance MimeResponds. This # module gives you the respond_to method. Adding it is quite simple, # you just need to include the module in a specific controller or in # +ApplicationController+ in case you want it available in your entire # application: # # class ApplicationController < ActionController::API # include ActionController::MimeResponds # end # # class PostsController < ApplicationController # def index # @posts = Post.all # # respond_to do |format| # format.json { render json: @posts } # format.xml { render xml: @posts } # end # end # end # # Quite straightforward. Make sure to check ActionController::Base # available modules if you want to include any other functionality that is # not provided by ActionController::API out of the box. class API < Metal abstract! # Shortcut helper that returns all the ActionController::API modules except # the ones passed as arguments: # # class MetalController # ActionController::API.without_modules(:ForceSSL, :UrlFor).each do |left| # include left # end # end # # This gives better control over what you want to exclude and makes it easier # to create an API controller class, instead of listing the modules required # manually. def self.without_modules(*modules) modules = modules.map do |m| m.is_a?(Symbol) ? ActionController.const_get(m) : m end MODULES - modules end MODULES = [ AbstractController::Rendering, UrlFor, Redirecting, Rendering, Renderers::All, ConditionalGet, RackDelegation, BasicImplicitRender, StrongParameters, ForceSSL, DataStreaming, # Before callbacks should also be executed as early as possible, so # also include them at the bottom. AbstractController::Callbacks, # Append rescue at the bottom to wrap as much as possible. Rescue, # Add instrumentations hooks at the bottom, to ensure they instrument # all the methods properly. Instrumentation, # Params wrapper should come before instrumentation so they are # properly showed in logs ParamsWrapper ] MODULES.each do |mod| include mod end ActiveSupport.run_load_hooks(:action_controller, self) end end