Comment on REST Controller for RAILS by Peter Williams

Mon, 27 Mar 2006 17:04:18 -0700

I posted a response to this at http://pezra.barelyenough.org/blog/2006/03/another-rest-controller-for-rails/

Comment on REST Controller for RAILS by Dan Kubb

Mon, 27 Mar 2006 18:47:39 -0700

Hi Charlie,

I’m glad you and Peter are working on this, the different perspectives are interesting to read.

From what I can tell its only the three of us looking at RESTful per-HTTP method dispatching in Rails – would you (and Peter) be interested in collaborating?

On your specific implementation: my original Rails Rest Controller has a nearly identical API to yours. (with small cosmetic differences of course) You referenced my third interation in your post, but the first two are somewhat similar to yours. Here’s the announcement for RestController #1:

http://microformats.org/discuss/mail/microformats-rest/2005-November/000042.html

Starting last fall I began developing an application around my RestController, and I found one specific problem that I think you’ll run into soon since our APIs are similar.

The problem is that for any given Resource, there will be a part of code where you instantiate the models. The code will be nearly identical for each per-method handler. (or should be, since the HTTP methods should be able to act on the same models) Your example does show a similar pattern in the Member resource, but it really won’t become prominent until you’re using multiple models in a single resource.

To get around this I thought about making a special handler for initialization. Instead I decided to just use a plain rails action, and make the per-method handlers just be blocks that are executed when the request method matches, like so:

  def collection
    conditions << @books = Book.find(:all)

    resource.post do
      @book = @books.build(params[:book])
      if @book.save
        render_post_success :action => 'by_id', :id => @book
      else
        render :action => 'new', :status => HTTP::Status::BAD_REQUEST
      end
    end
  end

The advantage to this is that I can wrap a block within an if statement, and restrict access to method handlers on a per user basis. Its also less of a jump for normal rails developers and that problem you noted where the templates need to be named according to the request method goes away too.

Also since each method is defined in a block, the API allows you to define response caching on a per-method basis, something I’ve found really helpful in practice.

After developing with the above style for the last couple of months it seems more natural than my old approach.

Comment on REST Controller for RAILS by Charlie

Wed, 29 Mar 2006 11:15:06 -0700

Hi Dan,

Thanks for the very interesting comment - and it would be great to collaborate. When I wrote this post, I wasn’t aware that you had written a new version of your rest controller. You’re idea is quite intriguing, let me digest it a bit and then I’ll post another article.

cfis : REST Controller for RAILS

Comment on REST Controller for RAILS by Peter Williams

Comment on REST Controller for RAILS by Dan Kubb

Comment on REST Controller for RAILS by Charlie