Making Rails' session work with Facebook

When using Facebook and ActiveRecordStore for sessions in Rails, rails generates a new session for every request. The following is a quick solution to the problem. First change your application's session_key by adding the following to the bottom of environment.rb.

ActionController::Base.session_options['session_key'] = 'fb_sig_session_key'

Next, override ActiveRecordStore#initialize to by adding the following to the bottom of environment.rb

class CGI
 class Session
   class ActiveRecordStore
     def initialize(session, option = nil)
       session_id = session.session_id
       unless @session = ActiveRecord::Base.silence { @@session_class.find_by_session_id(session_id) }
         @session = @@session_class.new(:session_id => session_id, :data => {})
       end
     end
   end
 end
end

Then restart your server. Your session should now persist between requests and have the same id as fb_sig_session_key.

Changing form element names

Last night's facebook update is incompatible with the way the rails handles form parameters. "object[field_1]" becomes "object" => "Array" instead of "object" => {"field_1" => ...}. Until the issue is resolved, a simple fix is to tell rails to name forms using parentheses instead of brackets. Additionally, rails will need to parse parentheses in parameter keys as brackets. The following code does just that. To use, just slap it at the bottom of your environment.rb.

module ActionView
 module Helpers
   class InstanceTag
     def tag_name
       "#{@object_name}(#{@method_name})"
     end
   
     def tag_name_with_index(index)
       "#{@object_name}(#{index})(#{@method_name})"
     end
   end
 end
end

class CGIMethods
 def self.parse_request_parameters(params)
   parser = FormEncodedPairParser.new

   params = params.dup
   until params.empty?
     for key, value in params
       if key.blank?
         params.delete key
       elsif !key.include?('(') && !key.include?('[')
         # much faster to test for the most common case first (GET)
         # and avoid the call to build_deep_hash
         parser.result[key] = get_typed_value(value[0])
         params.delete key
       elsif value.is_a?(Array)
         parser.parse(key.tr('()', '[]'), get_typed_value(value.shift))
         params.delete key if value.empty?
       else
         raise TypeError, "Expected array, found #{value.inspect}"
       end
     end
   end
   parser.result
 end
end