Question

This is a weird one I know. I’m trying to tie together two Rails applications, a v3 and a v2.3.5

I want them to share the same domain, and in order to do that without changing the URLs in the older app, I’m trying to find a way to override the Rails router.

I want the newer app living at the root of the domain, and the older one under several directories. For example:

/          => app1 # v3
/users     => app1
/employees => app2 # v2.3.5
/payrolls  => app2

So, since app1 lives at root and I’m using Passenger, I only have to create symlinks in the public folder of app1 to the public folder of app2, like so:

app1/public/employees => app2/public
app1/public/payrolls  => app2/public

And then I add RailsBaseURI /employees and RailsBaseURI /payrolls to Apache’s config.

With that I can make old URLs of app2 work, but inside the app, the links point to a prefix. For example, /employees/1, /employees/employees/1, /payrolls/employees/1 all work, but links in the app point to /employees/employees/1 and /payrolls/employees/1 depending on which prefix I’m currently on.

So, I need to remove that prefix from the links so only the old URLs work.

I need to do this in order to release the newer app. In time I’ll upgrade the older one to v3 and work directly on this issue, but right now any hack is ok just to make it work.

I don’t expect a solution, but if you can point me in the right direction on where to look in Rails source, or maybe a simpler approach I’m not seeing, I’d be very grateful.

Answer 1

Turns out it’s pretty easy just by overriding url_for in the ApplicationHelper like so:

def url_for(options = {})
  original = super(options)
  # I tried this in order to improve performance:
  return original unless original.starts_with?('/employees/employees')
  original.gsub('/employees/employees', '/employees')
end

However, this caused intermittent errors in the app that I wasn’t able to pinpoint. I suppose it’s because of the performance hit.

So in the end I was forced to use a different domain for the newer apps.