require 'active_support/core_ext/array/extract_options'
require 'action_controller/metal/mime_responds'
module ActionController #:nodoc:
module RespondWith
extend ActiveSupport::Concern
included do
class_attribute :responder, :mimes_for_respond_to
self.responder = ActionController::Responder
clear_respond_to
end
module ClassMethods
# Defines mime types that are rendered by default when invoking
# <tt>respond_with</tt>.
#
# respond_to :html, :xml, :json
#
# Specifies that all actions in the controller respond to requests
# for <tt>:html</tt>, <tt>:xml</tt> and <tt>:json</tt>.
#
# To specify on per-action basis, use <tt>:only</tt> and
# <tt>:except</tt> with an array of actions or a single action:
#
# respond_to :html
# respond_to :xml, :json, except: [ :edit ]
#
# This specifies that all actions respond to <tt>:html</tt>
# and all actions except <tt>:edit</tt> respond to <tt>:xml</tt> and
# <tt>:json</tt>.
#
# respond_to :json, only: :create
#
# This specifies that the <tt>:create</tt> action and no other responds
# to <tt>:json</tt>.
def respond_to(*mimes)
options = mimes.extract_options!
only_actions = Array(options.delete(:only)).map(&:to_s)
except_actions = Array(options.delete(:except)).map(&:to_s)
hash = mimes_for_respond_to.dup
mimes.each do |mime|
mime = mime.to_sym
hash[mime] = {}
hash[mime][:only] = only_actions unless only_actions.empty?
hash[mime][:except] = except_actions unless except_actions.empty?
end
self.mimes_for_respond_to = hash.freeze
end
# Clear all mime types in <tt>respond_to</tt>.
#
def clear_respond_to
self.mimes_for_respond_to = Hash.new.freeze
end
end
# For a given controller action, respond_with generates an appropriate
# response based on the mime-type requested by the client.
#
# If the method is called with just a resource, as in this example -
#
# class PeopleController < ApplicationController
# respond_to :html, :xml, :json
#
# def index
# @people = Person.all
# respond_with @people
# end
# end
#
# then the mime-type of the response is typically selected based on the
# request's Accept header and the set of available formats declared
# by previous calls to the controller's class method +respond_to+. Alternatively
# the mime-type can be selected by explicitly setting <tt>request.format</tt> in
# the controller.
#
# If an acceptable format is not identified, the application returns a
# '406 - not acceptable' status. Otherwise, the default response is to render
# a template named after the current action and the selected format,
# e.g. <tt>index.html.erb</tt>. If no template is available, the behavior
# depends on the selected format:
#
# * for an html response - if the request method is +get+, an exception
# is raised but for other requests such as +post+ the response
# depends on whether the resource has any validation errors (i.e.
# assuming that an attempt has been made to save the resource,
# e.g. by a +create+ action) -
# 1. If there are no errors, i.e. the resource
# was saved successfully, the response +redirect+'s to the resource
# i.e. its +show+ action.
# 2. If there are validation errors, the response
# renders a default action, which is <tt>:new</tt> for a
# +post+ request or <tt>:edit</tt> for +patch+ or +put+.
# Thus an example like this -
#
# respond_to :html, :xml
#
# def create
# @user = User.new(params[:user])
# flash[:notice] = 'User was successfully created.' if @user.save
# respond_with(@user)
# end
#
# is equivalent, in the absence of <tt>create.html.erb</tt>, to -
#
# def create
# @user = User.new(params[:user])
# respond_to do |format|
# if @user.save
# flash[:notice] = 'User was successfully created.'
# format.html { redirect_to(@user) }
# format.xml { render xml: @user }
# else
# format.html { render action: "new" }
# format.xml { render xml: @user }
# end
# end
# end
#
# * for a JavaScript request - if the template isn't found, an exception is
# raised.
# * for other requests - i.e. data formats such as xml, json, csv etc, if
# the resource passed to +respond_with+ responds to <code>to_<format></code>,
# the method attempts to render the resource in the requested format
# directly, e.g. for an xml request, the response is equivalent to calling
# <code>render xml: resource</code>.
#
# === Nested resources
#
# As outlined above, the +resources+ argument passed to +respond_with+
# can play two roles. It can be used to generate the redirect url
# for successful html requests (e.g. for +create+ actions when
# no template exists), while for formats other than html and JavaScript
# it is the object that gets rendered, by being converted directly to the
# required format (again assuming no template exists).
#
# For redirecting successful html requests, +respond_with+ also supports
# the use of nested resources, which are supplied in the same way as
# in <code>form_for</code> and <code>polymorphic_url</code>. For example -
#
# def create
# @project = Project.find(params[:project_id])
# @task = @project.comments.build(params[:task])
# flash[:notice] = 'Task was successfully created.' if @task.save
# respond_with(@project, @task)
# end
#
# This would cause +respond_with+ to redirect to <code>project_task_url</code>
# instead of <code>task_url</code>. For request formats other than html or
# JavaScript, if multiple resources are passed in this way, it is the last
# one specified that is rendered.
#
# === Customizing response behavior
#
# Like +respond_to+, +respond_with+ may also be called with a block that
# can be used to overwrite any of the default responses, e.g. -
#
# def create
# @user = User.new(params[:user])
# flash[:notice] = "User was successfully created." if @user.save
#
# respond_with(@user) do |format|
# format.html { render }
# end
# end
#
# The argument passed to the block is an ActionController::MimeResponds::Collector
# object which stores the responses for the formats defined within the
# block. Note that formats with responses defined explicitly in this way
# do not have to first be declared using the class method +respond_to+.
#
# Also, a hash passed to +respond_with+ immediately after the specified
# resource(s) is interpreted as a set of options relevant to all
# formats. Any option accepted by +render+ can be used, e.g.
#
# respond_with @people, status: 200
#
# However, note that these options are ignored after an unsuccessful attempt
# to save a resource, e.g. when automatically rendering <tt>:new</tt>
# after a post request.
#
# Three additional options are relevant specifically to +respond_with+ -
# 1. <tt>:location</tt> - overwrites the default redirect location used after
# a successful html +post+ request.
# 2. <tt>:action</tt> - overwrites the default render action used after an
# unsuccessful html +post+ request.
# 3. <tt>:render</tt> - allows to pass any options directly to the <tt>:render<tt/>
# call after unsuccessful html +post+ request. Usefull if for example you
# need to render a template which is outside of controller's path or you
# want to override the default http <tt>:status</tt> code, e.g.
#
# respond_with(resource, render: { template: 'path/to/template', status: 422 })
def respond_with(*resources, &block)
if self.class.mimes_for_respond_to.empty?
raise "In order to use respond_with, first you need to declare the " \
"formats your controller responds to in the class level."
end
mimes = collect_mimes_from_class_level
collector = ActionController::MimeResponds::Collector.new(mimes, request.variant)
block.call(collector) if block_given?
if format = collector.negotiate_format(request)
_process_format(format)
options = resources.size == 1 ? {} : resources.extract_options!
options = options.clone
options[:default_response] = collector.response
(options.delete(:responder) || self.class.responder).call(self, resources, options)
else
raise ActionController::UnknownFormat
end
end
protected
# Before action callback that can be used to prevent requests that do not
# match the mime types defined through <tt>respond_to</tt> from being executed.
#
# class PeopleController < ApplicationController
# respond_to :html, :xml, :json
#
# before_action :verify_requested_format!
# end
def verify_requested_format!
mimes = collect_mimes_from_class_level
collector = ActionController::MimeResponds::Collector.new(mimes, request.variant)
unless collector.negotiate_format(request)
raise ActionController::UnknownFormat
end
end
alias :verify_request_format! :verify_requested_format!
# Collect mimes declared in the class method respond_to valid for the
# current action.
def collect_mimes_from_class_level #:nodoc:
action = action_name.to_s
self.class.mimes_for_respond_to.keys.select do |mime|
config = self.class.mimes_for_respond_to[mime]
if config[:except]
!config[:except].include?(action)
elsif config[:only]
config[:only].include?(action)
else
true
end
end
end
end
end