cow is a web framework in the sense that it allows users to create tornado applications with configuration, templates and static files very easily without being a different beast.

cow automates most of the boring parts of tornado, allowing users to write only the part that actually matters: the handlers.

Installing cow is as easy as:

pip install cow-framework

After installing cow, go to the folder where you want to create your application and type:

cow myproject

This command will create the basic infrastructure for your project:

• server.py - the heart of your app and the place where you should put your handlers;
• templates - folder where you can store all your applications templates;
• static - folder where your static files should go;
• config - folder where your configuration files should be;
• config/init.py - module where you can declare your configuration default values.

Running your new application is as easy as:

python server.py

To confirm that your application is running, type the following command:

curl http://localhost:4444/healthcheck/

You should get as the result the string WORKING.

If you open server.py, you'll see that it has a method called get_handlers that should return a list of handlers that will be passed to tornado. This is where you can put your own handlers.

Suppose we have a HelloWorldHandler that writes Hello World to our users, like the following:

from tornado.web import RequestHandler

class HelloWorldHandler(RequestHandler):
    def get(self):
        self.write("Hello World!")

Then in our server.py Server class, we need to add it to a route, like this:

from cow.server import Server as CowServer
from myproject.handlers.hello_world import HelloWorldHandler

class Server(CowServer):
    def get_handlers(self):
        return (
            ('/', HelloWorldHandler),
        )

Now if you run server.py and access http://localhost:4444/ you should see the string Hello World.

It's really simple. You can use tornado's AsyncHTTPTestCase, like this:

from tornado.testing import AsyncHTTPTestCase
from myproject.server import Server  # the same server as in the above code

class TestHelloWorld(AsyncHTTPTestCase):
    def get_app(self):
        return Server().application

    def test_hello_world(self):
        response = self.fetch('/')
        assert response.code == 200
        assert response.body == 'Hello World'