I'm running typo on mod_ruby. It works fine, but some trivial fixes are required. If you want to run typo by Apache::RailsDispatcher, please apply the following patch.

=== config/environment.rb
==================================================================
--- config/environment.rb  (revision 264)
+++ config/environment.rb  (local)
@@ -82,7 +82,8 @@

 # Include your app's configuration here:
 $KCODE = 'u'
-require_dependency 'jcode'
+#require_dependency 'jcode'
+require 'jcode'
 require_dependency 'aggregations/delicious'
 require_dependency 'aggregations/tada'
 require_dependency 'aggregations/flickr'
@@ -96,4 +97,4 @@

 ActiveSupport::CoreExtensions::Time::Conversions::DATE_FORMATS.merge!(
   :long_weekday => '%a %B %e, %Y %H:%M'
-)
\ No newline at end of file
+)
=== lib/spam_protection.rb
==================================================================
--- lib/spam_protection.rb  (revision 264)
+++ lib/spam_protection.rb  (local)
@@ -111,7 +111,7 @@
   end
 end

-module ActiveRecord
+ActiveRecord.module_eval(<<EOF)
   module Validations
     module ClassMethods
       def validates_against_spamdb(*attr_names)
@@ -133,4 +133,4 @@
       end
     end
   end
-end
\ No newline at end of file
+EOF
=== lib/transforms.rb
==================================================================
--- lib/transforms.rb  (revision 264)
+++ lib/transforms.rb  (local)
@@ -12,7 +12,7 @@
   text.gsub(tag, '').gsub(/\s+/, ' ').strip
 end

-class String
+class Object::String
   # Converts a post title to its-title-using-dashes
   # All special chars are stripped in the process  
   def to_url
@@ -35,4 +35,4 @@

     result
   end
-end
\ No newline at end of file
+end

I implemented Apache::RailsDispatcher to run Rails applications on mod_ruby. You have to use the SVN HEAD version of mod_ruby to use it.

Apache::RailsDispatcher can run multiple applications in the same process. It works like this:

• require loads libraries into the top level, and they are shared with all applications.
• require_dependency loads libraries into an anonymous module for each application.
• In the development environment, the anonymous module is orphaned on each request. So required_dependency loads libraries every time.
• In the production environment, the same anonymous module is used for the same application. So required_dependency loads libraries only at once.
• Rails configurations such as ActiveRecord::Base.colorize_logging are reset on each request.

This hack is just a workaround until YARV supports multiple VM instances. We can get it in the near future, I hope.

To use Apache::RailsDispatcher, you have to write the following configuration in httpd.conf.

RubySafeLevel 0
# If you use RubyGem
# RubyRequire rubygems
RubyRequire apache/rails-dispatcher
RubyTransHandler Apache::RailsDispatcher.instance
<Location /appname>
  SetHandler ruby-object
  RubyHandler Apache::RailsDispatcher.instance
  RubyOption rails_uri_root /appname
  RubyOption rails_root /path/to/rails/root
  RubyOption rails_env production
</Location>

Please note that you can't override exinting classes like this:

class Array
  def cycle()
    self.each_with_index {|o, i| yield(o, %w(odd even)[i % 2])}
  end
end

You should prepend Object:: to the class name:

class Object::Array
  def cycle()
    self.each_with_index {|o, i| yield(o, %w(odd even)[i % 2])}
  end
end

This behaivour is same as Kernel.load(filename, true). If you don't like this, please convince Matz to change it.