Rails Magazine - Issue 3

folder as shown in Figure 2. Once we’re finished with the
GUI, we can create the back-end.
First, we’ll create a Rails application using the rails command.
Second we will need a model to store the product's
data so we will execute this command:
$ script/generate model Product name:string
description:string price:float
Now we need to configure our database. By default Rails
2 offers a simple configuration for an SQLite database, so we
will use that. The next step is to run the migration:
$ rake db:migrate
Now we need a controller to manage the client's requests:
$ script/generate controller products
Our backend is finished for now. The next step is to configure
connection between it and the front-end.
RubyAMF
In this example, we’ve created two datagrids (Figure 3).
One will use AMF to communicate with the server. The other
will use HTTPService. We’ll cover AMF First.
Fortunately for Rails developers, we have the RubyAMF
rails plugin which will do a lot of the heavy lifting. Installation
is easy. Just type the following:
$ script/plugin install http://rubyamf.googlecode.com/
svn/tags/current/rubyamf
When installation is finished we will be ready to write a
little code for our Rails application. In the config folder we can
find a file called rubyamf_config.rb that includes the mapping
between our ActiveRecord class and our ActionScript class.
But we don’t have an ActionScript class! Let’s write one. It
will map to the product model that we just created in rails. In
the Flex project, create a new subfolder of src called valueobject
and new ActionScript class called Product. This is the code
for the new Product.as file:
package valueobj
{
[RemoteClass(alias=”Product”)]
public class Product
{
public var id:int;
public var name:String;
public var description:String;
public var price:Number;
public var createdAt:Date;
public var updatedAt:Date;
Ruby on Rails & Flex: Building a new software generation by Arturo Fernandez
}
}
/**
* Constructor
*/
public function Product()
{
}
Notice that the public attributes of this class match those
in our Rails model. We also declare that RemoteClass is Product
– our Rails model class.
Now go back to rubyamf_config.rb and add these lines of
code:
ClassMappings.register(
:actionscript => ‘Product’,
:ruby => ‘Product’,
:type => ‘active_record’,
:attributes => [“id”,”name”,”description”, “price”,
“created_at”, “updated_at”]
)
Wings to the moon
Now that we’ve mapped the Flex Product class to the Rails
Product class, we can load the data into our grid. You’ll need to
set the dataProvider property of the datagrid component:
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