CacheCliene for Tornado

CacheClient is a simple HTTPClient wrapper for the Tornado web framework. CacheClient is used by Graypools to fetch remote data sources and cache the results. It uses an sqlite3 backend for quick read/writes and a very basic thread-locking mechanism for managing multiple asynchronous fetches.

The CacheClient is under ongoing development. Please feel free to submit any pull requests or issues, and we'll be happy to address them.

Hello, world

Here is the CacheClient interacting with Tornado's "Hello, world" example:

import tornado.ioloop
import tornado.web
from tornado import gen
from client import CacheClient

class MainHandler(tornado.web.RequestHandler):
    def get(self):
        self.write("Hello, world")

application = tornado.web.Application([
    (r"/", MainHandler),
])

loop = tornado.ioloop.IOLoop.instance()
client = CacheClient(loop)

@gen.coroutine
def _fetch_it():
    response = yield client.fetch('http://localhost/') # Fetch live.
    print(response.buffer.read())
    assert response.fresh == True
    response = yield client.fetch('http://localhost/') # fetch cached
    print(response.buffer.read())
    assert response.fresh == False  # See?
    client.cache.clear()  # Clean up
    loop.stop()

if __name__ == "__main__":
    application.listen(80)  # Will need to be root.
    loop.add_callback(_fetch_it)
    loop.start()