ETag magic with Django
An ETag is a feature of HTTP that allows for a web server to know if content has changed since the last time the browser visited the page. The client sends the ETag from the cached page in a header. If the ETag in the header matches the current ETag then the server lets the browser know that the cached is up-to-date by sending back a 304 Not Modified response.
Fast Caching with Django and Nginx
I've been toying with optimizing the caching on my blog recently – for my own interest (this humble blog doesn't get all that much traffic). All the same, any speed improvements will only mean snappier page-loads and greater capacity to handle a slashdotting, or similar.
I discovered that Nginx has a memcached module that can serve pages directly from memcached without touching the file-system, or a downstream web-app. Which makes for very fast response times. To get it working, you need to set a cache key named with the url of the page, and the value to the HTML. Alas, this means that it would not work with Django's caching mechanism due to the way Django caches unique pages based on the contents of the request header.
