Question

We have an old legacy PHP application. Now I want to write a new application module using Ruby on Rails.

Deployment is a one problem. I guess that it should be possible to run PHP app (via mod_php) and RoR app (via mod_proxy / mongrel) on a one Apache server. I don’t want to use mod_rails because it requires to run php via fcgi. So is a risk of breaking something. Both PHP and RoR will use the same DB.

The tricky part is how to pass login info from PHP application to RoR app. Users login into PHP and their info is stored in PHP session data. The RoR app will be placed in a subdirectory of main PHP app (eg http://www.example.com/railsapp). So RoR should receive all HTTP cookies. And the question is how to extract PHP session data from RoR app.

Above this is just my first idea which is rather bad because of possible race conditions between PHP mod and RoR. I can modify the PHP app to store some info in DB when a user logs in. But I don’t know how to handle a case when PHP session data expired and some data in DB should be updated (logout a user).

Does anyone solved similar problem? Or at least can point a most promising direction?

Update: It should be possible to configure mod_php to store session data in sql DB. In this way there will be no race conditions. DB engine should prevent race conditions.

Update2: Actually it is possible to use mod_rails with Apache in prefork mode. Which is required by the mod_php. It is just recommended for mod_rails to run Apache in worker mpm mode. So the whole deployment of PHP / RoR apps is greatly simplified.

Answer 1

First, if you are placing the rails app in a sub directory it is possible to use mod_rails. In your configuration for the PHP site you can have a location that has a root for rails.

<Location /railsapp>   DocumentRoot /.../app/public </Location> 

To get a session over to the rails side, you could either create a connect page on the rails and call it from the PHP side and pass in some data to login. You just need to protect this page from any request not from the localhost (easy to do).

You could also switch rails to use a database to store its sessions, you should then be able to generate a session id, store it in a cookie with the correct name and secret, and create a session in the database manually with that id.

You can also (which I recommend) have proxy page on the rails side which logs the user in and redirects them to their desired page. You could do it like this (not actual working code, but you get the idea):

PHP

$key = md5hash($user_id . $user_password_hash . $timestamp) $url = '/railsapp/proxy?userid=' . $user_id . '&key=' . $key . '&page=home%2Fwelcome' <a href='<$ $url $>'>Rails App</a> 

Rails

map.proxy 'proxy', :controller => 'proxy', :action => 'connect'  class ProxyController < ActionController::Base   def connect     key = ...     if params[:key] == key       login_user params[:userid]       redirect_to params[:page]     else       render :nothing, :status => 403     end   end end