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Godfrey Chan

2012-Aug-29 20:44 UTC

respond_with and namespaced controllers

# in routes.rb

MyAwesomeSite::Application.routes.draw do
  namespace :api do
    namespace :v1 do
      resources :topics
    end
  end
end

# in app/controllers/api/v1/topics_controller.rb

class API::V1::TopicsController < API::V1::APIController
  def create
    respond_with Topic.create(params[:topic])
  end
end

This unfortunately won''t work, as it is going to complain about the
missing topic_url helper.

Instead I''ll have to do this:

class API::V1::TopicsController < API::V1::APIController
  def create
    topic = Topic.create(params[:topic])
    respond_with topic, location: api_v1_topic_url(topic)
  end
end

But this still won''t work, because when there are validation errors in
topic, api_v1_topic_url will raise an exception. So you''ll need…

class API::V1::TopicsController < API::V1::APIController
  def create
    topic = Topic.build(params[:topic])
    if topic.save
      respond_with topic, location: api_v1_topic_url(topic)
    else
      respond_with topic
    end
  end
end

…which almost defeats the purpose of using respond_with in the first place.

Did I miss any obvious solution? If not, I''d like to see improve this.
I have a few ideas:

1. In the URL helpers, return nil instead of raising an exception

2. Accept a proc for the location option in respond_with. Since respond_with
won''t even look at the location option when there are errors in the
object passed in, the proc will only be called when the object was saved
successfully and thus avoids the exception in the url helper:

class API::V1::TopicsController < API::V1::APIController
  def create
    topic = Topic.create(params[:topic])
    respond_with topic, location: ->{ api_v1_topic_url(topic) }
  end
end

3. Respect the controller''s namespace when constructing the location
object, so it will try to use api_v1_topic_url, api_topic_url and topic_url in
that order.

My favourite is #3, but I''d have to do some research to find out how to
do this or if it''s possible at all. Any comments / feedback / pointers
are welcomed!

Godfrey



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Tomas Varneckas

2012-Aug-29 22:37 UTC

head link

Re: respond_with and namespaced controllers

Hi,

This seems to work well for me:
def create
  respond_with :api, :v1, Topic.create(params[:topic])
end

Is this the behavior you want?

The documentation for respond_with is pretty detailed and mentions this
solution (under nested resources):
http://apidock.com/rails/ActionController/Responder

Your 3rd suggestion is something that could be done by writing a custom
responder if this seems like boilerplate to you.
Looking at your code, your model is not namespaced, so technically it is
behaving correctly. If it were namespaced under
Api::V1 same as the controller it would just work without any hints
(because the path is generated based on model_name).

On Wed, Aug 29, 2012 at 11:44 PM, Godfrey Chan <godfreykfc@gmail.com>
wrote:> # in routes.rb
>
> MyAwesomeSite::Application.routes.draw do
>   namespace :api do
>     namespace :v1 do
>       resources :topics
>     end
>   end
> end
>
> # in app/controllers/api/v1/topics_controller.rb
>
> class API::V1::TopicsController < API::V1::APIController
>   def create
>     respond_with Topic.create(params[:topic])
>   end
> end
>
> This unfortunately won''t work, as it is going to complain about
the
missing> topic_url helper.
>
> Instead I''ll have to do this:
>
> class API::V1::TopicsController < API::V1::APIController
>   def create
>     topic = Topic.create(params[:topic])
>     respond_with topic, location: api_v1_topic_url(topic)
>   end
> end
>
> But this still won''t work, because when there are validation
errors in
> topic, api_v1_topic_url will raise an exception. So you''ll need…
>
> class API::V1::TopicsController < API::V1::APIController
>   def create
>     topic = Topic.build(params[:topic])
>     if topic.save
>       respond_with topic, location: api_v1_topic_url(topic)
>     else
>       respond_with topic
>     end
>   end
> end
>
> …which almost defeats the purpose of using respond_with in the first
place.>
> Did I miss any obvious solution? If not, I''d like to see improve
this. I
> have a few ideas:
>
> 1. In the URL helpers, return nil instead of raising an exception
>
> 2. Accept a proc for the location option in respond_with. Since
respond_with> won''t even look at the location option when there are errors in
the object
> passed in, the proc will only be called when the object was saved
> successfully and thus avoids the exception in the url helper:
>
> class API::V1::TopicsController < API::V1::APIController
>   def create
>     topic = Topic.create(params[:topic])
>     respond_with topic, location: ->{ api_v1_topic_url(topic) }
>   end
> end
>
> 3. Respect the controller''s namespace when constructing the
location
object,> so it will try to use api_v1_topic_url, api_topic_url and topic_url in
that> order.
>
> My favourite is #3, but I''d have to do some research to find out
how to do
> this or if it''s possible at all. Any comments / feedback /
pointers are
> welcomed!
>
> Godfrey
>
>
>
> --
> You received this message because you are subscribed to the Google Groups
> "Ruby on Rails: Core" group.
> To post to this group, send email to rubyonrails-core@googlegroups.com.
> To unsubscribe from this group, send email to
> rubyonrails-core+unsubscribe@googlegroups.com.
> For more options, visit this group at
> http://groups.google.com/group/rubyonrails-core?hl=en.
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Godfrey Chan

2012-Aug-30 01:35 UTC

head link

Re: respond_with and namespaced controllers

> def create
>   respond_with :api, :v1, Topic.create(params[:topic])
> end
That works great! Didn''t make the connection between singleton
resources and namespaces the first time I saw it. I''m quite happy with
this solution!
> Looking at your code, your model is not namespaced, so technically it is
behaving correctly. If it were namespaced under Api::V1 same as the controller
it would just work without any hints (because the path is generated based on
model_name).

I understand that the path is currently generated based on model_name, but I
wasn''t sure if this is the most sensible default, since this code
resides in the controller, it could make use of the information to make a better
guess at the naming (it seems quite unlikely to cause problem, because if your
models are namespaced, chances are your controllers are also namespaced, but the
reverse is not typically true outside of engines). I guess I''d try
implementing the custom responder in my app and see how that goes, and if that
worked out well for me I might open a PR and see what others think.

Thanks again for your help, really appreciate it!

Godfrey

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Rails core - Aug 2012 - respond_with and namespaced controllers

respond_with and namespaced controllers

Re: respond_with and namespaced controllers

Re: respond_with and namespaced controllers