invalid byte sequence in US-ASCII (Ruby 1.9 + rails 2.3.8 + mongodb + mongo_mapper)

Question

My setup is:

linux + Ruby 1.9 + rails 2.3.8 + mongodb + mongo_mapper

I followed http://railscasts.com/episodes/194-mongodb-and-mongomapper, that everything is OK

Answer 1

I had this error with a Rack application.

Adding

   Encoding.default_external = Encoding::UTF_8

   Encoding.default_internal = Encoding::UTF_8

to config.ru resolved it for me.