我是RoR的初学者 .
我正在使用Android应用程序将文件上传到服务器（rails） .
上传适用于单个文件，有时适用于多个文件 .
我已经跟踪堆栈跟踪并显示了一些变量，但我不明白为什么会发生错误 .
在错误期间，第二个文件在名称中无法识别，但它正在根据文件类型进行识别 .
我不明白为什么它对这些特定文件起作用，如下所示 .
请帮我理解这个 .
当它不起作用时：
tag_multipart_encoding（filename，content_type，name）中的数据：
Floyd.txt
纯文本/
上传文件[]
图像/ JPEG
日志：
[2015-11-15 07:52:29] ERROR NoMethodError：未定义方法force_encoding'为nil：NilClass /home/pi/.rvm/gems/ruby-2.2.1/gems/rack-1.6.4/lib/ rack / multipart / parser.rb：197：intag_multipart_encoding'/home/pi/.rvm/gems/ruby-2.2.1/gems/rack-1.6.4/lib/rack/multipart/parser.rb:76:in block （2级）解析'/home/pi/.rvm/gems/ruby-2.2.1/gems/rack-1.6.4/lib/rack/multipart/parser.rb:252:inget_data'/ home / pi / .rvm / gems / ruby-2.2.1 / gems / rack-1.6.4 / lib / rack / multipart / parser.rb:75:as in parse'/home/pi/.rvm/gems/ruby-2.2 . 1 / gems / rack-1.6.4 / lib / rack / multipart / parser.rb:56:inloop'/home/pi/.rvm/gems/ruby-2.2.1/gems/rack-1.6.4/lib/ rack / multipart / parser.rb：56：in parse'/home/pi/.rvm/gems/ruby-2.2.1/gems/rack-1.6.4/lib/rack/multipart.rb:25:inparse_multipart'/ home / pi / .rvm / gems / ruby-2.2.1 / gems / rack-1.6.4 / lib / rack / request.rb:376：in parse_multipart'/home/pi/.rvm/gems/ruby-2.2 . 1 / gems / rack-1.6.4 / lib / rack / request.rb:208:inPOST'/home/pi/.rvm/gems/ruby-2.2.1/gems/rack-1.6.4/lib/rack/ methodoverride.rb ：39：in method_override_param'/home/pi/.rvm/gems/ruby-2.2.1/gems/rack-1.6.4/lib/rack/methodoverride.rb:27:inmethod_override'/home/pi/.rvm/ gems / ruby-2.2.1 / gems / rack-1.6.4 / lib / rack / methodoverride.rb：15：in call'/home/pi/.rvm/gems/ruby-2.2.1/gems/rack-1.6 .4 / lib / rack / runtime.rb：18：incall'/home/pi/.rvm/gems/ruby-2.2.1/gems/activesupport-4.2.3/lib/active_support/cache/strategy/local_cache_middleware.rb ：28：在电话'/home/pi/.rvm/gems/ruby-2.2.1/gems/rack-1.6.4/lib/rack/lock.rb:17:incall'/home/pi/.rvm/ gems / ruby-2.2.1 / gems / actionpack-4.2.3 / lib / action_dispatch / middleware / static.rb:116：in call'/home/pi/.rvm/gems/ruby-2.2.1/gems/rack -1.6.4 / lib / rack / sendfile.rb：113：incall'/home/pi/.rvm/gems/ruby-2.2.1/gems/railties-4.2.3/lib/rails/engine.rb:518 ：在电话'/home/pi/.rvm/gems/ruby-2.2.1/gems/railties-4.2.3/lib/rails/application.rb:165:incall'/home/pi/.rvm/gems/ ruby-2.2.1 / gems / rack-1.6.4 / lib / rack / lock.rb:17:in call'/home/pi/.rvm/gems/ruby-2.2.1/gems/rack-1.6.4 /lib/rack/content_length.rb:15:incall '/home/pi/.rvm/gems/ruby-2.2.1/gems/rack-1.6.4/lib/rack/handler/webrick.rb:88:in service'/home/pi/.rvm/rubies/ ruby-2.2.1 / lib / ruby / 2.2.0 / webrick / httpserver.rb:138：inservice'/home/pi/.rvm/rubies/ruby-2.2.1/lib/ruby/2.2.0/webrick/ httpserver.rb:94：运行'/home/pi/.rvm/rubies/ruby-2.2.1/lib/ruby/2.2.0/webrick/server.rb:294:inblock in start_thread'
当它工作时：
tag_multipart_encoding（filename，content_type，name）中的数据：
Megadeth Set.png
图像/ PNG
上传文件[]
tmp1.txt
纯文本/
上传文件[]
日志：
在2015-11-15 08:12:58 0530开始发布“/ upload”for 192.168.1.2无法从192.168.1.2渲染控制台！允许的网络：127.0.0.1，:: 1,127.0.0.0/127.255.255.255由HomeController处理#upload作为HTML参数：{“fileUpload”=> [＃，@ original_filename =“Megadeth Set.png”，@ content_type =“ image / png“，@ headers =”Content-Disposition：form-data; name = \“fileUpload [] \”; filename = \“Megadeth Set.png \”\ r \ nConContent-Type：image / png \ r \ nContent-Transfer-Encoding：binary \ r \ n“>，＃，@ original_filename =”tmp1.txt“，@ content_type =”text / plain“，@ headers =”Content-Disposition：form-data; name = \“ fileUpload [] \“; filename = \”tmp1.txt \“\ r \ nConContent-Type：text / plain \ r \ nContent-Transfer-Encoding：binary \ r \ n”>]}