Oliver’s Place

This article is the second one in my article series about fast loading web pages. The first article dealt with the Django Framework while this one is about Grails which I have recently elected as my preferred rapid web application framework. Ever since I switched from Django to Grails there was one issue that bothered me and that was the loss of the ability to serve complete pre-rendered pages from a distributed cache to the enduser while bypassing the application server.

The solution described in this article is in use on the production servers powering mmogle.com where it ensures page response times below 100ms for cached content.

Let me summarize the concept for readers not familiar with my first article: The goal we want to achieve is to greatly decrease the load on the application server (container) by storing the raw HTML output of rendered pages in a (distributed-) cache to be picked up by a Frontend Web Server without even bothering the application server behind it for the current request. Since we would need stuff like Edge Side Includes (ESI) for dealing with personalized pages, we are going limit ourselves to anonymous users.

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Inspired by this article I decided to find out if the same technique can be exploited in my current project which is developed in django.

My first problem was to come up with a viable cache key scheme since simply using the full request URI as suggested in the article wouldn’t work for me because my site renders a different version of a navigation menu depending on the authentication state of current the user. After weighing in the advantages and disadvantages between the super clean variant of factoring the session cookie and all other cookies into the memcached key and a less heavy weight method that would only append a server supplied abstract “page version” field to the request URI, I went for the latter. My resulting nginx virtual host config was looking like this:

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