This is great! With the Talentsuche.de RubyOnRails app growing the mongrel development server was getting slow and slower. Lately a request took up to 3000ms - that's unusable for front end development.

But there is quick way to speed this up. Mongrels default behaviour is to listen on all interfaces/addresses (0.0.0.0). By setting a single ip you can make it a lot faster.

 ./script/server -b 10.23.23.23 -p 3000

To register a custom mime type in Rails, call the register method from your controller:

Mime::Type.register "image/jpeg", :jpg

Your mime type can be used in the respond_to block now:

format.jpg do 
  #do something
end

It's a really dirty hack. But String#split supports unicode by default, while String#gsub gets confused. However: the problem is fixed in 1.9.