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Revised description for responds_with

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1 parent bc8b55c commit 98b4ef730696062b624c508d22ca76d9caa018cc @MarkMT MarkMT committed Mar 17, 2012
Showing with 115 additions and 19 deletions.
  1. +115 −19 actionpack/lib/action_controller/metal/mime_responds.rb
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134 actionpack/lib/action_controller/metal/mime_responds.rb
@@ -195,20 +195,105 @@ def respond_to(*mimes, &block)
end
end
- # respond_with wraps a resource around a responder for default representation.
- # First it invokes respond_to, if a response cannot be found (ie. no block
- # for the request was given and template was not available), it instantiates
- # an ActionController::Responder with the controller and resource.
+ # For a given controller action, respond_with generates an appropriate
+ # response based on the mime-type requested by the client.
#
- # ==== Example
+ # If the method is called with just a resource, as in this example -
#
- # def index
- # @users = User.all
- # respond_with(@users)
+ # class PeopleController < ApplicationController
+ # respond_to :html, :xml, :json
+ #
+ # def index
+ # @people = Person.all
+ # respond_with @people
+ # end
# end
#
- # It also accepts a block to be given. It's used to overwrite a default
- # response:
+ # then the mime-type of the response will be 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+.
+ #
+ # If an acceptable response is not in the list of formats declared by
+ # +respond_to+, the application will return a '406 - not acceptable'
+ # status code. Otherwise, the default response will 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 was +get+, an exception
+ # will be 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 will +redirect+ to the resource
+ # i.e. its +show+ action.
+ # 2. If there are validation errors, the response
+ # will instead render a default action, which is <tt>:new</tt> for a
+ # +post+ request or <tt>:edit</tt> for +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 +responds_with+ responds to <code>to_<format></code>,
+ # the method will attempt 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 potentially 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 the redirection of successful html requests, +respond_with+ also supports
+ # the use of nested resources, which are supplied in the same way as you do
+ # 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 will be 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])
@@ -219,13 +304,24 @@ def respond_to(*mimes, &block)
# end
# end
#
- # All options given to respond_with are sent to the underlying responder,
- # except for the option :responder itself. Since the responder interface
- # is quite simple (it just needs to respond to call), you can even give
- # a proc to it.
- #
- # In order to use respond_with, first you need to declare the formats your
- # controller responds to in the class level with a call to <tt>respond_to</tt>.
+ # 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) will be 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.
+ #
+ # Two 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.
#
def respond_with(*resources, &block)
raise "In order to use respond_with, first you need to declare the formats your " <<
@@ -279,8 +375,8 @@ def retrieve_collector_from_mimes(mimes=nil, &block) #:nodoc:
end
end
- # A container of responses available for requests with different mime-types
- # sent to the current controller action.
+ # A container for responses available from the current controller for
+ # requests for different mime-types sent to a particular action.
#
# The public controller methods +respond_with+ and +respond_to+ may be called
# with a block that is used to define responses to different mime-types, e.g.

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