Referer (sic) - Headers & Cookies

I've been looking at solutions to track users when moving between WRN partner repositories. This is needed so that we can associate items viewed across the repositories rather than just within a repository.

I can think of a several ways of doing this (and there are probably many more!)

• Using IP addresses
• Using the optional Referer (sic) HTTP request Header field
• Using Cookies e.g. Google Analytics
• Using Apache logs

We'd rather not expose IP addresses (although we could encrypt them with a shared symmetric key, for example) so I think I will be looking at the other options.

The cookies used by Google Analytics for tracking are quite interesting. We could enable all the repositories with Google Analytics and then retrieve the data from the __utmz cookie.

On the other hand we could get the information from Apache logs and use this but for now I think the simplest method will be to just retrieve the referer (sic) from the request header using good old Java!

Here's a simple referer test using a servlet (JSP).

More on this later..