What is FastCGI?

FastCGI is a language independent, webserver-independent, scalable, open extension to CGI that provides high performance without the limitations of server specific APIs.

Using FastCGI with Rails

Unix/Linux/BSD

If you are using Apache you will need mod_fcgi, and the FastCGI? Development kit; These can be obtained from http://www.fastcgi.com . You will also need ruby-fcgi.

Note that official FastCGI with Apache 2 is considered unreliable, a prefered module for use with Apache 2 and up, mod_fcgid can be found here: http://fastcgi.coremail.cn/
(Also found in major package systems)

You can do the install manually or using your package manager.

Package Managers

Download and install mod_fcgi from your distributions package management system of choice. A good resource is http://rpm.pbone.net/

1. Gentoo:
   

   
   emerge fcgi ruby-fcgi mod_fastcgi
   
   

   
   Then edit /etc/apache(2)/modules/_mod_fastcgi.conf as described below. Add -D FASTCGI to /etc/conf.d/apache(2)
2. Debian/Ubuntu:
   Under debian and ubuntu, run
   

    
   
   apt-get install libapache-mod-fastcgi libfcgi-ruby1.8
   
   

   
   (for apache 2, replace libapache with libapache2).
3. Fedora
   Under Fedora, there is no package for mod_fcgi. See RailsOnFedora for a step by step guide to getting FCGI working in Fedora.

Manually

1. Install the FastCGI? Devel kit.
   

   
   $ wget <a href="http://www.fastcgi.com/dist/fcgi-2.4.0.tar.gz">www.fastcgi.com/dist/fcgi-2.4.0.tar.gz</a> 
   $ tar zxvf fcgi-2.4.0.tar.gz
   $ cd fcgi-2.4.0
   $ ./configure
   $ sudo make install
   
   

2. Install ruby-fcgi. To be able to compile this gem, you might need libfcgi-dev:
   

   
   $ sudo apt-get install libfcgi-dev
   $ sudo gem install fcgi
   
   

   
   some systems may need: (FreeBSD for example)
   

   
   $ sudo gem install fcgi -- --with-fcgi-include=/usr/local/include --with-fcgi-lib=/usr/local/lib
   
   

   
   (ToDo: expand on this)

1. add the following to your apache httpd. conf
   

   
   LoadModule fastcgi_module /usr/lib/apache2/modules/mod_fastcgi.so
   <IfModule mod_fastcgi.c>
       FastCgiIpcDir /tmp/fcgi_ipc/
       AddHandler fastcgi-script .fcgi
   </IfModule>
   
   

   
   You may have mod_fastcgi.so installed in a different place. If so, use the correct path.
2. reload apache with
   

   
   $ apache2ctl reload
   
   

   
   Use apachectl if you are not using apache2
3. change directories to your rails app
4. in public/dispatch.fcgi you may have to change
   

   
   require 'fcgi'
   
   

   
   to
   

   
   require 'rubygems'
   require_gem 'fcgi'
   
   

   
   NOTE: in Rails 1.0.0 there is no require ‘fcgi’ in the dispatch.fcgi, so this change is not needed. If you are running a old rails version just update all your installed gems using :
   

   
   $ sudo gem update
   
   

5. in public/.htaccess change
   

   
   RewriteRule ^(.*)$ /dispatch.cgi?$1 [QSA,L]
   
   

   
   to
   

   
   RewriteRule ^(.*)$ /dispatch.fcgi?$1 [QSA,L]
   
   

thanks to ((Jarkko Laine))

For me (Mefiboset) this did not work, I used this instead:

RewriteRule ^(.*)$ /dispatch.fcgi$1 [L]

Make sure your rails environment is correct!

If your app (or an opensource app like typo or hierarki) is working fine using a webbrick server normaly started with:

$ ./script/server -e production

but the fastcgi version keeps returning error messages, check out the environment settings in the file config/environment.rb, it should contain a line like this:

ENV['RAILS_ENV'] ||= 'production'

It took me a long night without sleep to find this out.

Also note that testing dispatch.fcgi from the command line can reveal interesting errors:

$ public/dispatch.fcgi

If you get Ruby errors you should fix these first, however if you see a

Status: 500 Internal Server Error

this may be a good sign: it seems the normal response if dispatch.fcgi is run from the command line !.

If you get errors

• The dispatch.fcgi or dispatch.cgi has an incorrect path to Ruby. This won’t be the case if you used the ocs-install-rails script, but if you developed on another machine, please make sure the path is #!/usr/bin/ruby in all scripts that include a Ruby path at the top (including the dispatch scripts in public folder and the generators and other utilities in the script folder)

• Make sure your app folder owner is the same as the webserver (ie. nobody)

• Make sure that the dispatch.fcgi and dispatch.cgi scripts have 0755 (-rwxr-xr-x) permissions.

• Make sure you are accessing the Rails app with a trailing / after the URL, like yoursite.com/rails/ instead of yoursite.com/rails

• If you have previously tested the application, you may need to clear old session files, which are found in tmp/sessions

• You may also need to chmod tmp/sessions 777 or sort it so the fcgi process can write session files into that directory

See Also

• Lighttpd and FastCGI
• Fast CGI and Apache2 for Red Hat Linux 9
• HowToUseOracleWithFastCGI
• Fast CGI with Apache2 and RHEL 4
• Debian mod_fastcgi Notes
• HowtoSetupApacheWithFastCGIAndRubyBindings
• FastCGI on OS X
• FastCGI on unix linux bsd
• HowtoInstallAndRunRubyOnRailsOnCpanel (Cpanel and easyapache specific FCGI instructions)
• How To Configure Sun Java System Web Server 7.0
• HowtoSetupIIS

For Windows systems

• FastCGI installation under Windows

Resources

• FCGIRubyWhyArentMyChangesDisplayed

Troubleshooting

If you get in your log files something along the lines of “dispatch.fcgi has failed to remain running for 30 seconds given 3 attempts, its restart interval has been backed off to 600 seconds” then you need to edit public/dispatch.fcgi and dispatch.rb to change the location of ruby on the first line to the correct location on your deployment machine – this is especially important if you’ve developed on Windows and are deploying on Unix

If you get error: undefined method `is_cgi?’

because native fcgi.so not loaded correctly.
fcgi.so depends on libfcgi.so.0

add this to /etc/ld.so.conf:

/usr/local/lib

then type: /sbin/ldconfig
retry again

Side Note: The above says to use apachectl or apache2ctl to restart apache. However, several linux distros use scripts in /etc/init.d to control daemon processes like apache. If you have such a directory, check to see if there’s an apache script in there!.