Recently I was given the task of integrating a (complete for all intents and purposes) PHP application with our main Ruby on Rails application. Because the PHP application needed to display a similar interface and required knowledge of the user’s account, I needed a way to access that data from the database both applications were now sharing. The only real requirement I had was that I absolutely didn’t want to make the user login to the PHP app if they were already authenticated on the Rails side of things as this seemed unnecessary and interrupted the flow things.

I did a bit of searching and, while I did find the wiki page on going from PHP -> Rails, I wasn’t able to find anything that fit my specific need, so I set out to roll my own. I read an article this morning from somebody who had ostensibly encountered the same problem as I, and was able to come up with a much different solution than what I had come up with. Therefore I thought it would be fun to share some of the details of my approach....