Ajax, Rails 2.0.2, and the FastCGI Problem

I encountered an error today with a Rails Ajax drag ‘n drop and sortable list I developed for a client. Scouring the production logs, I saw:

/!\ FAILSAFE /!\  Wed Apr 16 14:19:18 -0500 2008
Status: 500 Internal Server Error
can't modify frozen string

After some Googling, I saw a couple posts in the Ruby on Rails talk Google Group. Sure enough, others were experiencing the problem, but there was no reported solution. Apparently there is even a patch in the Rails core — or at least a ticket in for the problem. But, I don’t think that is necessary, because I came up with a solution without having to patch the core.

Turns out it was a configuration problem, specifically the error was due to the .htaccess file in the /public directory of my application.

Here are the steps I took to resolve the issue:

1. I changed the line that read

   RewriteRule ^(.*)$ dispatch.cgi [QSA,L]

   to the following:

   RewriteRule ^(.*)$ dispatch.fcgi [QSA,L]

2. Then I commented out the fastcgi-script handler line, as such:

   # General Apache options
   
   # AddHandler fastcgi-script .fcgi

3. And, voila!, there is no step three.

Now my spiffy management tool works the way it was intended. Hope this helps someone looking for an answer to this issue.