ActionView::Template::Error (incompatible character encodings: UTF-8 and ASCII-8BIT)
I am using Ruby 1.9.2, Rails 3.0.4/3.0.5 and Phusion Passenger 3.0.3/3.0.4. My templates are written in HAML and I am using the MySQL2 gem. I have a controller action that when passed a parameter that has a special character, like an umlaut, gives me the following error:
ActionView::Template::Error (incompatible character encodings: UTF-8 and ASCII-8BIT)
The error points to the first line of my HAML template, which has the following code on it:
<!DOCTYPE html>
My understanding is that this is caused because I have a UTF-8 string that is being concatenated with an ASCII-8BIT string, but I can't for the life of me figure out what that ASCII-8BIT string is. I have checked that the params in the action are encoded using UTF-8 and I have added an encoding: UTF-8 declaration to the top of the HAML template and the ruby files and I still get this error. My application.rb file has a config.encoding = "UTF-8" declaration in it as well and the following all result in UTF-8:
ENV['LANG']
__ENCODING__
Encoding.default_internal
Encoding.default_external
Here's the kicker: I cannot reproduce this result locally on my Mac-OSX using standalone passenger or mongrel in either development or production. I can only reproduce it on a production server running nginx+passenger on linux. I have verified in the production server's console that the latter mentioned commands all result in UTF-8 as well.
Have you experienced this same error and how did you solve it?
Answer
After doing some debugging I found out the issue occurs when using the ActionDispatch::Request object which happens to have strings that are all coded in ASCII-8BIT, regardless of whether my app is coded in UTF-8 or not. I do not know why this only happens when using a production server on Linux, but I'm going to assume it's some quirk in Ruby or Rails since I was unable to reproduce this error locally. The error occurred specifically because of a line like this:
@current_path = request.env['PATH_INFO']
When this instance variable was printed in the HAML template it caused an error because the string was encoded in ASCII-8BIT instead of UTF-8. To solve this I did the following:
@current_path = request.env['PATH_INFO'].dup.force_encoding(Encoding::UTF_8)
Which forced @current_path to use a duplicated string that was forced into the proper UTF-8 encoding. This error can also occur with other request related data like request.headers.