Fix to_param unicode string gsub bug on jruby

14 June 2013

万恶的Windows系统下跑rails应用

伟大的国家单位只给我提供windows系统的服务器，我只能在有限的条件下发挥无限的本能去跑心爱的rails。
最初使用Nginx + Thin + Ruby 1.9，速度是一个字—-慢。
穷则思变，为了性能，我把 Rails 从 ruby 环境迁移到 JRuby，结果速度还真的比MRI要快很多。但有得必有失，原先为了url读的方便，我把 model的 to_param 重新定义了，采用了名称作为缺省的params:id,在

jruby -S trinidad

之后，可恶的事情发生了。

application error
org.jruby.exceptions.RaiseException: (ArgumentError) invalid byte sequence in GBK
        at org.jruby.RubyString.gsub(org/jruby/RubyString.java:3051)
        at org.jruby.RubyString.gsub(org/jruby/RubyString.java:3019)
        at RUBY.escape_glob_chars(E:/downloads/jruby-bin-1.7.0/jruby-1.7.0/lib/ruby/gems/shared/gems/actionpack-3.2.2/lib/action_dispatch/middleware/static.rb:41)
        at RUBY.match?(E:/downloads/jruby-bin-1.7.0/jruby-1.7.0/lib/ruby/gems/shared/gems/actionpack-3.2.2/lib/action_dispatch/middleware/static.rb:14)
        at RUBY.call(E:/downloads/jruby-bin-1.7.0/jruby-1.7.0/lib/ruby/gems/shared/gems/actionpack-3.2.2/lib/action_dispatch/middleware/static.rb:55)
        at RUBY.call(E:/downloads/jruby-bin-1.7.0/jruby-1.7.0/lib/ruby/gems/shared/gems/railties-3.2.2/lib/rails/engine.rb:479)
        at RUBY.call(E:/downloads/jruby-bin-1.7.0/jruby-1.7.0/lib/ruby/gems/shared/gems/railties-3.2.2/lib/rails/application.rb:220)
        at RUBY.call(file:E:/downloads/jruby-bin-1.7.0/jruby-1.7.0/lib/ruby/gems/shared/gems/jruby-rack-1.1.10/lib/jruby-rack-1.1.10.jar!/rack/handler/servlet.rb:22)

伪解决方案

看这个原因，应该是Jruby 没有按照程序的要求使用 utf-8 编码，还是按照 console 环境的编码 GBK进行字符串的处理。苦逼的中国人，编个程序还要比老外要复杂些。看了看 stackoverflow, 提出的解决方案是

#environment.rb
Encoding.default_external = Encoding::UTF_8
Encoding.default_internal = Encoding::UTF_8

照做，继续失败。

最终解决方案

ruby 最能干的事情就是开包，其次就是把A搞成B, B搞成A，实践 Metaprogramming 的时候到了。

# config/initializers/jruby_patch.rb
require 'action_dispatch/middleware/static'

module ActionDispatch
  class FileHandler
    alias_method :match_orig?, :match?

    def match_helper?(path)
      ec = Encoding::Converter.new 'gbk', 'utf-8'
      path = ec.convert path
      match_orig? path.to_s
    end

    alias_method :match?, :match_helper? 
  end
end

世界又恢复正常了:)

ruby 5