Technical Q&A QA1494

Why is my Ruby on Rails application with FastCGI generating "'load error /etc/irbrc" errors?

Q: Why is my Ruby on Rails application with FastCGI generating "load error /etc/irbrc" errors?

A: If you're hosting Ruby on Rails applications on Mac OS X 10.5 or Mac OS X 10.5 Server with FastCGI, you may encounter an error when accessing your application, accompanied by an error in the Apache error log, similar to the message in Listing 1 :

Listing 1: Sample Apache error log message from FastCGI.

[error] [client ::1] FastCGI: comm with server "/Library/WebServer/Documents/demoapp/dispatch.fcgi" aborted:
error parsing headers: malformed header 'load error /etc/irbrc'

To resolve this, first back up your current /etc/irbrc file and then replace it with the contents of Listing 2 (this requires admin privileges), and then restart your web server.

Listing 2: Replace your /etc/irbc file with these lines.

require 'irb/completion'
require 'irb/ext/save-history'
ARGV.concat [ "--readline", "--prompt-mode", "simple" ]
IRB.conf[:SAVE_HISTORY] = 100
IRB.conf[:HISTORY_FILE] = "#{ENV['HOME']}/.irb-save-history"

Here is one way of doing this from within Terminal:

Make a backup of /etc/irbrc

% sudo mv /etc/irbrc /etc/irbc.orig

Create and edit a new, empty copy of /etc/irbrc

% sudo pico /etc/irbrc

Copy Listing 2 and paste it into the new document, then save the file by pressing, in order, "Control-X" (Exit), "Y" (Yes), and "Return".

Change the permissions of /etc/irbrc to match the original (Read-only for User, Group and Others)

% sudo chmod a=r /etc/irbrc

Finally, restart Apache

% sudo apachectl graceful

Internal: <rdar://problem/5517579>

Document Revision History

Posted: 2007-11-28