Yesterday Ext <a href="http://extjs.com/blog/2009/06/03/ext-js-30-rc2-release-stable-robust-and-enhanced/">released</a> 
the second release candidate of Ext JS 3.0.
It included a new restful configuration option for the <a 
href="http://extjs.com/deploy/ext-3.0-rc2/docs/?class=Ext.data.Store">Ext.data.Store</a> and <a 
href="http://extjs.com/deploy/ext-3.0-rc2/examples/restful/restful.html">an example for its usage</a>.

Impressed by Ext's Chris Scott's lightweight Rails-like PHP MVC framework, I still wanted to get a feeling for this new 
feature by writing a Rails backend for this example.

<h4>Here it is</h4>
<a 
href="http://github.com/steffen/extjswithrails.restful.sample/">http://github.com/steffen/extjswithrails.restful.sample/
</a>

<h4>Here is what I did</h4>
On the frontend, I only changed the Proxy's URL from
<pre name="code" class="js:nocontrols">
var proxy = new Ext.data.HttpProxy({
  url: 'app.php/users'
});
</pre>
to
<pre name="code" class="js:nocontrols">
var proxy = new Ext.data.HttpProxy({
  url: '/users'
});
</pre>
On the backend side, I created the User model, added the model to the routes.rb file, and created the following users 
controller:
(I didn't do all by hand, thanks to <em>script/generate scaffold user
email:string first:string last:string</em> :))
<pre name="code" class="ruby:nocontrols">
class UsersController < users =" User.all" json =""> { :data => @users }
end

def create
  @user = User.new(ActiveSupport::JSON.decode(params[:data]))

  if @user.save
    render :json => { :success => true, :message => "Created new User #{@user.id}", :data => @user }
  else
    render :json => { :message => "Failed to create user"}
  end
end

def update
  @user = User.find(params[:id])

  if @user.update_attributes(ActiveSupport::JSON.decode(params[:data]))
    render :json => { :success => true, :message => "Updated User #{@user.id}", :data => @user }
  else
    render :json => { :message => "Failed to update User"}
  end
end

def destroy
  @user = User.find(params[:id])

  if @user.destroy
    render :json => { :success => true, :message => "Destroyed User #{@user.id}" }
  else
    render :json => { :message => "Failed to destroy User" }
  end
end

end
</pre>
Notice that the scaffold actions expects the data through the <em>user</em> parameter (params[:user]), but Ext's example 
is using <em>data</em> as root, that's why we have to use params[:data] here.

Check the <a href="http://github.com/steffen/extjswithrails.restful.sample/commits/master">commit log</a> for details 
regarding the steps it took me to create this example.

<h4>Here is how you can try it out</h4>
<ol>
<li>$ git clone git://github.com/steffen/extjswithrails.restful.sample.git</li>
<li>$ cd extjswithrails.restful.sample</li>
<li>Make sure you have ruby 1.8, rubygems, rails 2.3.2 and sqlite3-ruby  installed.</li>
<li>$ rake db:migrate</li>
<li>$ script/server</li>
<li>Open http://localhost:3000/javascripts/ext/examples/restful-with-rails/restful.html in browser.</li>
</ol>

<h4>Here is what gave me a headache</h4>
Unfortunately, Ext JS isn't sending the whole data in JSON, but rather as normal POST parameters with one parameter that 
carries the JSON string. That parameter's name is taken from the root option from your reader, in our example its 
<em>data</em>.

I think there should be two things fixed:
<ol>
<li>Send the whole data in JSON, such as <em>{ id: 1, data: { first: 'First', last: 'Last', email: 'Email' } }</em> and 
not as <em>id=1&amp;data={ first: 'First', last: 'Last', email: 'Email' }</em>.

The current workaround is to use <em>ActiveSupport::JSON.decode</em>
for the <em>data</em> parameter, since Rails can't automatically decode the parameters because the request isn't 
completely in JSON.</li>
<li>Send the AJAX request with the request header <em>'Content-Type': application/json</em>. This way, if the request 
would completely be in JSON, Rails could figure out that it receives JSON data.

A workaround would be to add <em>Ext.Ajax.defaultHeaders = { 'Content-Type': 'application/json' }</em></li>
</ol>

<h4>Conclusion</h4>
The restful option rocks! :)