Brubeck is a flexible Python web framework that aims to make the process of building scalable web services easy.
The Brubeck model resembles what companies build when they operate at large scale, yet the experience couldn't be much simpler.
Build for scale at the same time you're prototyping your idea.
This is a whole Brubeck application.
class DemoHandler(WebMessageHandler):
def get(self):
self.set_body('Hello world')
return self.render()
urls = [(r'^/', DemoHandler)]
mongrel2_pair = ('ipc://127.0.0.1:9999', 'ipc://127.0.0.1:9998')
app = Brubeck(mongrel2_pair=mongrel2_pair,
handler_tuples=urls)
app.run()
Brubeck gets by with a little help from these friends:
- Mongrel2: lean & fast, asynchronous web serving
- Eventlet: non-blocking I/O & coroutines
- ZeroMQ: fast messaging & supports most languages
- DictShield: data modeling & validation with no database opinions
Listsurf is a simple to way to save links. Yeah... another delicious clone!
It serves as a basic demonstration of what a complete site looks like when you built with Brubeck. It has authentication with secure cookies, offers a JSON API, uses Jinja2 for templating and stores data in MongoDB.
In this section we'll discuss writing request handler, adding user authentication and rendering pages with templates.
The framework can be used for different requirements. It can be lean and lightweight for high throughput or you can fatten it up and use it for rendering pages in a database backed CMS.
The general architecture of the system is to map requests for a specific URL to some callable to handle it. The configuration attempts to match handlers to URL's by inspecting a list of (url pattern, callable) tuples.
Some people like to use classes as handlers. Some folks prefer to use functions. Brubeck supports both.
When a class model is used, the class will be instantiated for the life of the request and then thrown away. This makes building state for each request fairly easy, since you can just attach members to self knowing that memory will be back soon.
Brubeck's MessageHandler design is similar to what you see in Facebook's Tornado, or web.py.
To answer HTTP GET requests, implement get() on a WebMessageHandler instance.
class DemoHandler(WebMessageHandler):
def get(self):
self.set_body('Take five!')
return self.render()
Then we add DemoHandler to the routing config instantiate a Brubeck instance.
That looks like this:
urls = [(r'^/brubeck', DemoHandler)]
config = {
'handler_tuples': urls,
...
}
Brubeck(**config).run()
If you'd prefer to just use a simple function, you instantiate a Brubeck instance and wrap your function with the add_route decorator.
That looks like this:
app = Brubeck(mongrel2_pair=('ipc://127.0.0.1:9999',
'ipc://127.0.0.1:9998'))
@app.add_route('^/brubeck', method='GET')
def foo(application, message):
return http_response('Take five!', 200, 'OK', {})
app.run()
Templates support is contained in brubeck.templates as rendering mixins. Brubeck currently supports Jinja2 or Tornado templates.
Each Mixin will attach a render_template function to your handler and overwrite the default render_error to produce templated errors messages.
Using a template system is then as easy as calling render_template with the template filename and some context, just like you're used to.
Using Jinja2 template looks like this.
from brubeck.templating import Jinja2Rendering
class DemoHandler(WebMessageHandler, Jinja2Rendering):
def get(self):
context = {
'name': 'J2 D2',
}
return self.render_template('success.html', **context)
Tornado templates are supported by the TornadoRendering mixin. The code looks virtually the same to keep mixing template systems lightweight.
from brubeck.templating import TornadoRendering
class DemoHandler(WebMessageHandler, TornadoRendering):
...
Authentication can be provided by decorating functions with the @web_authenticated decorator. This decorator expects the handler to have a current_user property that returns either an authenticated User model or None.
The UserHandlingMixin provides functionality for authenticating a user and creating the current_user property.
The work that's required will depend on how you build your system. The authentication framework uses a DictShield Document to create the User model, so you can implement a database query or check user information in a sorted CSV. Either way, you still get the authentication framework you need.
In practice, this is what your code looks like.
from brubeck.auth import web_authenticated, UserHandlingMixin
class DemoHandler(WebMessageHandler, UserHandlingMixin):
@web_authenticated
def post(self):
...
The User model in brubeck.auth will probably serve as a good basis for your needs. A Brubeck user looks roughly like below.
class User(Document):
"""Bare minimum to have the concept of a User.
"""
username = StringField(max_length=30, required=True)
password = StringField(max_length=128)
...
If you need a session to persist, you can use Brubeck's secure cookies to track users.
You first add the cookie secret to your Brubeck config.
config = {
'cookie_secret': 'OMGSOOOOSECRET',
...
}
You then attempt to retrieve the cookie value by passing the application's secret key into the get_cookie function.
# Try loading credentials from secure cookie
user_id = self.get_cookie('user_id',
secret=self.application.cookie_secret)
What you do from there is up to you.