Rails ArgumentError: invalid %-encoding

by

if you don’t mind against monkeypatching Rack then create in config/initializers file (for example rack.rb) with this content:

module Rack
  module Utils
    if defined?(::Encoding)
      def unescape(s, encoding = Encoding::UTF_8)
        begin
          URI.decode_www_form_component(s, encoding)
        rescue ArgumentError
          URI.decode_www_form_component(URI.encode(s), encoding)
        end
      end
    else
      def unescape(s, encoding = nil)
        begin
          URI.decode_www_form_component(s, encoding)
        rescue ArgumentError
          URI.decode_www_form_component(URI.encode(s), encoding)
        end
      end
    end
    module_function :unescape
  end
end

p.s. it works with passenger, but with Webrick and Thin it doesn’t. It looks like both webrick and thin parse a request too, so the failure happens before initializer is loaded. For example with Thin error happens in thin-1.6.2/lib/thin/request.rb:84.

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