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Class: ActionController::API

Overview

API Controller is a lightweight version of 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, 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.

Normally, ApplicationController is the only controller that inherits from 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 Base.

Renders

The default API Controller stack includes all renderers, which means you can use render :json and siblings 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_to in all actions, otherwise it will return 204 No Content.

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_to method in your controllers in the same way as in 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 Base that is not present by default in 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

Make sure to check the modules included in Base if you want to use any other functionality that is not provided by API out of the box.

Constant Summary

::AbstractController::Rendering - Included

DEFAULT_PROTECTED_INSTANCE_VARIABLES

Redirecting - Included

ILLEGAL_HEADER_VALUE_REGEX

Renderers - Included

RENDERERS

Rendering - Included

RENDER_FORMATS_IN_PRIORITY

::ActiveSupport::Callbacks - Included

CALLBACK_FILTER_TYPES

ParamsWrapper - Included

EXCLUDE_PARAMETERS

Class Attribute Summary

Metal - Inherited

.middleware_stack, .middleware_stack?

::AbstractController::Base - Inherited

.abstract?

Alias for AbstractController::Base.abstract.
.supports_path?

Returns true if the given controller is capable of rendering a path.

Class Method Summary

Metal - Inherited

.action

Returns a ::Rack endpoint for the given action name.
.controller_name

Returns the last part of the controller’s name, underscored, without the ending Controller.
.dispatch

Direct dispatch to the controller.
.make_response!,
.middleware

The middleware stack used by this controller.
.new,
.use

Pushes the given ::Rack middleware and its arguments to the bottom of the middleware stack.

::AbstractController::Base - Inherited

.abstract,
.abstract!

Define a controller as abstract.
.action_methods

A list of method names that should be considered actions.
.clear_action_methods!

action_methods are cached and there is sometimes a need to refresh them.
.controller_path

Returns the full controller name, underscored, without the ending Controller.
.internal_methods

A list of all internal methods for a controller.
.method_added

Refresh the cached action_methods when a new action_method is added.

::ActiveSupport::DescendantsTracker - Extended

descendants

Instance Attribute Summary

Instrumentation - Included

#logger, #view_runtime

Rescue - Included

#rescue_handlers, #rescue_handlers?,
#show_detailed_exceptions?

Override this method if you want to customize when detailed exceptions must be shown.

::AbstractController::Callbacks - Included

#__callbacks

::AbstractController::Caching - self

#fragment_cache_keys, #fragment_cache_keys?

::AbstractController::Caching::ConfigMethods - Included

#cache_store, #cache_store=

StrongParameters - Included

#params

Returns a new Parameters object that has been instantiated with the request.parameters.
#params=

Assigns the given value to the params hash.

Renderers::All - Included

#_renderers, #_renderers?

Redirecting - Included

#logger

::AbstractController::UrlFor - Included

#default_url_options, #default_url_options?

::ActionView::ViewPaths - Included

#formats, #locale, #view_paths

Metal - Inherited

#content_type, #headers, #location, #media_type, #middleware_stack, #middleware_stack?, #params, #params=,
#performed?

Tests if render or redirect has already happened.
#request

:attr_reader: request.
#response

:attr_reader: response.
#response=

Assign the response and mark it as committed.
#response_body=, #session, #status

::AbstractController::Base - Inherited

#action_name

Returns the name of the action this controller is processing.
#formats

Returns the formats that can be processed by the controller.
#performed?

Tests if a response body is set.
#response_body

Returns the body of the HTTP response sent by the controller.

Instance Method Summary

Instrumentation - Included

#redirect_to, #render, #send_data, #send_file,
#append_info_to_payload

Every time after an action is processed, this method is invoked with the payload, so you can add more information.
#cleanup_view_runtime

A hook which allows you to clean up any time, wrongly taken into account in views, like database querying time.

::ActiveSupport::Rescuable - Included

#rescue_with_handler

Delegates to the class method, but uses the instance as the subject for rescue_from handlers (method calls, instance_exec blocks).

::ActiveSupport::Callbacks - Included

#run_callbacks

Runs the callbacks for the given event.

DataStreaming - Included

#send_data

Sends the given binary data to the browser.
#send_file

Sends the file.

Rendering - Included

#render

Renders a template and assigns the result to self.response_body.
#render_to_string

Similar to #render, but only returns the rendered template as a string, instead of setting self.response_body.

::AbstractController::Caching - self

#view_cache_dependencies,
#cache

Convenience accessor.

::AbstractController::Caching::Fragments - Included

#combined_fragment_cache_key

Given a key (as described in expire_fragment), returns a key array suitable for use in reading, writing, or expiring a cached fragment.
#expire_fragment

Removes fragments from the cache.
#fragment_exist?

Check if a cached fragment from the location signified by key exists (see expire_fragment for acceptable formats).
#read_fragment

Reads a cached fragment from the location signified by key (see expire_fragment for acceptable formats).
#write_fragment

Writes content to the location signified by key (see expire_fragment for acceptable formats).

ConditionalGet - Included

#expires_in

Sets the Cache-Control header, overwriting existing directives.
#expires_now

Sets an HTTP 1.1 Cache-Control header of no-cache.
#fresh_when

Sets the etag, last_modified, or both on the response, and renders a ‘304 Not Modified` response if the request is already fresh.
#http_cache_forever

Cache or yield the block.
#no_store

Sets an HTTP 1.1 Cache-Control header of no-store.
#stale?

Sets the etag and/or last_modified on the response and checks them against the request.

Head - Included

#head

Returns a response that has no content (merely headers).

Renderers - Included

#_render_to_body_with_renderer,
#render_to_body

Called by render in ::AbstractController::Rendering which sets the return value as the response_body.

ApiRendering - Included

#render_to_body

Redirecting - Included

#redirect_back

Soft deprecated alias for #redirect_back_or_to where the fallback_location location is supplied as a keyword argument instead of the first positional argument.
#redirect_back_or_to

Redirects the browser to the page that issued the request (the referrer) if possible, otherwise redirects to the provided default fallback location.
#redirect_to

Redirects the browser to the target specified in options.
#url_from

Verifies the passed location is an internal URL that’s safe to redirect to and returns it, or nil if not.

::ActiveSupport::Benchmarkable - Included

#benchmark

Allows you to measure the execution time of a block in a template and records the result to the log.

UrlFor - Included

#initialize, #url_options

::AbstractController::UrlFor - Included

#_routes

::ActionDispatch::Routing::UrlFor - Included

#initialize,
#route_for

Allows calling direct or regular named route.
#url_for

Generate a URL based on the options provided, default_url_options, and the routes defined in config/routes.rb.
#url_options

Hook overridden in controller to add request information with default_url_options.
#_routes_context, #_with_routes

::ActionDispatch::Routing::PolymorphicRoutes - Included

#polymorphic_path

Returns the path component of a URL for the given record.
#polymorphic_url

Constructs a call to a named RESTful route for the given record and returns the resulting URL string.

::AbstractController::Rendering - Included

#render

Normalizes arguments and options, and then delegates to render_to_body and sticks the result in self.response_body.
#render_to_body

Performs the actual template rendering.
#render_to_string

Similar to #render, but only returns the rendered template as a string, instead of setting self.response_body.
#rendered_format

Returns Content-Type of rendered content.
#view_assigns

This method should return a hash with assigns.
#_normalize_args

Normalize args by converting render "foo" to render action: "foo" and render "foo/bar" to render file: "foo/bar".
#_normalize_options

Normalize options.
#_process_options

Process extra options.

::ActionView::ViewPaths - Included

#any_templates?,
#append_view_path

Append a path to the list of view paths for the current LookupContext.
#details_for_lookup,
#lookup_context

LookupContext is the object responsible for holding all information required for looking up templates, i.e. view paths and details.
#prepend_view_path

Prepend a path to the list of view paths for the current LookupContext.
#template_exists?

Metal - Inherited

#controller_name

Delegates to the class’s .controller_name.
#reset_session,
#url_for

Basic url_for that can be overridden for more robust functionality.

::AbstractController::Base - Inherited

#action_methods

Delegates to the class’s .action_methods.
#available_action?

Returns true if a method for the action is available and can be dispatched, false otherwise.
#controller_path

Delegates to the class’s .controller_path.
#process

Calls the action going through the entire Action Dispatch stack.

::ActiveSupport::Configurable - Included

#config

Reads and writes attributes from a configuration OrderedOptions.

Constructor Details

This class inherits a constructor from ActionController::Metal

Class Method Details

.without_modules(*modules)

Shortcut helper that returns all the API modules except the ones passed as arguments:

class MyAPIBaseController < ActionController::Metal
  ActionController::API.without_modules(: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.

[ GitHub ] 

  


# File 'actionpack/lib/action_controller/api.rb', line 107



def self.without_modules(*modules)
  modules = modules.map do |m|
    m.is_a?(Symbol) ? ActionController.const_get(m) : m
  end

  MODULES - modules
end