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![Tornado] (http://www.tornadoweb.org/static/tornado.png)

Previously I had created backends for the Backbone.js todos example using Google App Engine and Django. Now it's the time for Tornado Web Server. Tornado is not a web framework so I had to add the SQLAlchemy ORM to the stack.

The main task, again, was to develop the RESTful handler to support the Backbone.js JSON interface.

class RESTfulHandler(BaseHandler):
    def get(self, id):
        ...
    def post(self, id):
        ...
    def put(self, id):
        ...
    def delete(self, id):
        ...

I've used the same Backbone.js todos application. So I pointed the collection (TodoList) to the url /todos.

window.TodoList = Backbone.Collection.extend({

    // Reference to this collection's model.
    model: Todo,

    // Save all of the todo items under the `"todos"` namespace.
    //localStorage: new Store("todos"),

    url: '/todos',

Then I mapped the url to the RESTful handler:

class Application(tornado.web.Application):
    def __init__(self):
        handlers = [
            (r"/", MainHandler),
            (r"/todos\/?([0-9]*)", RESTfulHandler),
        ]

The regular expression "/todos\/?([0-9]*)" match the Backbone.js RESTful interface HTTP methods and urls:

• read -> GET /todos[/id]
• create -> POST /todos
• update -> PUT /todos/id
• delete -> DELETE /todos/id

Once you've worked with the Django ORM, SQLAlchemy feels very natural.