Rails, respond_with and status

[Dagnan]

Hi.

When creating an object using respond_with, it renders the json or xml with status 201 (Created). I think with rabl it just renders the template with the status code 200.

Is it a bug or a normal behavior? And is there a way to merge both behaviors?

[Dagnan]

I was able to perform what I'm talking about in an initializer, maybe it can help seeing the big picture:

ActionController::Responder.class_eval do
  def to_format
    if has_errors?
      api_behavior(nil) and return
    end

    controller.response.status = :created if post? && ! has_errors?

    default_render
  rescue ActionView::MissingTemplate => e
    api_behavior(e)
  end
end

Now I understand a lot better Rails view stack. As for my problem, the culprit is this line in mime_responds.rb:

collector = Collector.new { default_render }

which calls the default view without options (I guess this is a functionality and not a bug since it's name is "default_render").

[haxney]

You can also achieve this by creating a subclass of ActionController::Responder and passing it to respond_with like this:

class MyResponder < ActionController::Responder
  def to_format
    case
    when has_errors?
      controller.response.status = :unprocessable_entity
    when post?
      controller.response.status = :created
    end

    binding.pry
    default_render
  rescue ActionView::MissingTemplate => e
    api_behavior(e)
  end
end

class UsersController < ApplicationController
  respond_to :json, :xml, :html

  def update
    @user.update_attributes(params[:user])
    respond_with(@user, :responder => MyResponder)
  end
end

This allows you to swap in and out responders as necessary, and avoids having to monkey-patch ActionController::Responder. If you want that behavior by default, you can add self.responder = MyResponder to your controllers or even your ApplicationController.

It might be worth including something like this in Rabl out of the box, since it is rather surprising behavior.

[nesquena]

Interesting, thanks for sharing the code snippet. I could see something like this being very useful. I typically use Rabl in Padrino and Rails 2.3 just because that's where my apps are which is why something like this isn't there by default. This is something I think would go well in the wiki though (added just now): https://github.com/nesquena/rabl/wiki/Response-Codes.

[Dagnan]

Thanks Haxney, this is certainly cleaner your way :)

[haxney]

Whoops, there shouldn't be that binding.pry in there. I had been using Pry for testing purposes and forgot to take it out!

If you want this behavior throughout all of your controllers, you can simply put self.responder = MyResponder in your ApplicationController, so that you don't have to specify respond_with(@user, :responder => MyResponder) in every function in your controllers.

[Govinda-Fichtner]

In the solution above I missed the errors in case something goes wrong. In the original responders there is this display_errors method which renders the errors.

class ApiResponder < ActionController::Responder
  def to_format
    case
    when has_errors?
      controller.response.status = :unprocessable_entity
      display_errors
    when post?
      controller.response.status = :created
      default_render
    end

  rescue ActionView::MissingTemplate => e
    api_behavior(e)
  end
end

It might be also a good idea to add this to the wiki page. It took me a while to find this page and to find out that it is RABL's fault that I get a 200 instead of a 201 for a create action and not mine. What is the reason that RABL doesn't do the above by default?

[mxrguspxrt]

For not having to change controller code, I use config/initializers/rabl_fix_status_codes.rb

class ActionController::Responder

  alias :to_format_original :to_format

  def to_format
    if post? || !has_errors?
      controller.response.status = :created
    end
    to_format_original
  end

end

[ansel1]

can use super too. And don't need to check for has_errors?. controller.response.status will be overwritten later in default to_format

In your application controller:

class MyAppResponder < ActionController::Responder
  def to_format
    controller.response.status = :created if post?
    super
  end
end

self.responder = MyAppResponder

super will change the status code to :unprocessable_entity if necessary. This code just sets the default status, which can still be overridden by render options, respond_with options, etc.

[nesquena]

If anyone wants to update /improve this page https://github.com/nesquena/rabl/wiki/Response-Codes that would helpful because it's where I point people who are interested in a 'smart' rabl responder.