Paperclip – nil的未定义方法`match’：NilClass
我是铁杆和ruby的新手。 我正在创建一个简单的应用程序，我可以上传照片。 我安装了paperclip gem，我正在尝试在我的模型中配置它以指定缩略图大小，如下所示：
has_attached_file :photo, :styles => {:thumb => '120x120>', :large => '640x480>' }, :default_style => :thumb, :url => "/system/photos/:basename.:extension", :path => ":rails_root/public/system/photos/:basename.:extension" 但是，我一直收到错误：
undefined method `match' for nil:NilClass
当我删除：styles参数时，一切都按预期工作。
任何人都可以解决一些问题并指出我正确的方向吗？
谢谢
编辑：
堆栈跟踪如下：
C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/bundler/gems/paperclip-70f0f1fea030/lib/paperclip/content_type_detector.rb:60:in `type_from_file_command' C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/bundler/gems/paperclip-70f0f1fea030/lib/paperclip/content_type_detector.rb:16:in `detect' C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/bundler/gems/paperclip-70f0f1fea030/lib/paperclip/io_adapters/file_adapter.rb:14:in `cache_current_values' C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/bundler/gems/paperclip-70f0f1fea030/lib/paperclip/io_adapters/file_adapter.rb:5:in `initialize' C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/bundler/gems/paperclip-70f0f1fea030/lib/paperclip/io_adapters/registry.rb:29:in `new' C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/bundler/gems/paperclip-70f0f1fea030/lib/paperclip/io_adapters/registry.rb:29:in `for' C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/bundler/gems/paperclip-70f0f1fea030/lib/paperclip/attachment.rb:412:in `post_process_style' C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/bundler/gems/paperclip-70f0f1fea030/lib/paperclip/attachment.rb:402:in `block in post_process_styles' C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/bundler/gems/paperclip-70f0f1fea030/lib/paperclip/attachment.rb:401:in `each' C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/bundler/gems/paperclip-70f0f1fea030/lib/paperclip/attachment.rb:401:in `post_process_styles' C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/bundler/gems/paperclip-70f0f1fea030/lib/paperclip/attachment.rb:394:in `block (2 levels) in post_process' activesupport (3.2.7) lib/active_support/callbacks.rb:403:in `_run__792123923__photo_post_process__530674861__callbacks' activesupport (3.2.7) lib/active_support/callbacks.rb:405:in `__run_callback' activesupport (3.2.7) lib/active_support/callbacks.rb:385:in `_run_photo_post_process_callbacks' activesupport (3.2.7) lib/active_support/callbacks.rb:81:in `run_callbacks' C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/bundler/gems/paperclip-70f0f1fea030/lib/paperclip/callbacks.rb:26:in `run_paperclip_callbacks' C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/bundler/gems/paperclip-70f0f1fea030/lib/paperclip/attachment.rb:393:in `block in post_process' activesupport (3.2.7) lib/active_support/callbacks.rb:403:in `_run__792123923__post_process__530674861__callbacks' activesupport (3.2.7) lib/active_support/callbacks.rb:405:in `__run_callback' activesupport (3.2.7) lib/active_support/callbacks.rb:385:in `_run_post_process_callbacks' activesupport (3.2.7) lib/active_support/callbacks.rb:81:in `run_callbacks' C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/bundler/gems/paperclip-70f0f1fea030/lib/paperclip/callbacks.rb:26:in `run_paperclip_callbacks' C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/bundler/gems/paperclip-70f0f1fea030/lib/paperclip/attachment.rb:392:in `post_process' C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/bundler/gems/paperclip-70f0f1fea030/lib/paperclip/attachment.rb:107:in `assign' C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/bundler/gems/paperclip-70f0f1fea030/lib/paperclip.rb:196:in `block in has_attached_file' activerecord (3.2.7) lib/active_record/attribute_assignment.rb:85:in `block in assign_attributes' activerecord (3.2.7) lib/active_record/attribute_assignment.rb:78:in `each' activerecord (3.2.7) lib/active_record/attribute_assignment.rb:78:in `assign_attributes' activerecord (3.2.7) lib/active_record/base.rb:498:in `initialize' activerecord (3.2.7) lib/active_record/persistence.rb:44:in `new' activerecord (3.2.7) lib/active_record/persistence.rb:44:in `create' app/controllers/photography_controller.rb:23:in `create' actionpack (3.2.7) lib/action_controller/metal/implicit_render.rb:4:in `send_action' actionpack (3.2.7) lib/abstract_controller/base.rb:167:in `process_action' actionpack (3.2.7) lib/action_controller/metal/rendering.rb:10:in `process_action' actionpack (3.2.7) lib/abstract_controller/callbacks.rb:18:in `block in process_action' activesupport (3.2.7) lib/active_support/callbacks.rb:414:in `_run__403597772__process_action__67609296__callbacks' activesupport (3.2.7) lib/active_support/callbacks.rb:405:in `__run_callback' activesupport (3.2.7) lib/active_support/callbacks.rb:385:in `_run_process_action_callbacks' activesupport (3.2.7) lib/active_support/callbacks.rb:81:in `run_callbacks' actionpack (3.2.7) lib/abstract_controller/callbacks.rb:17:in `process_action' actionpack (3.2.7) lib/action_controller/metal/rescue.rb:29:in `process_action' actionpack (3.2.7) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action' activesupport (3.2.7) lib/active_support/notifications.rb:123:in `block in instrument' activesupport (3.2.7) lib/active_support/notifications/instrumenter.rb:20:in `instrument' activesupport (3.2.7) lib/active_support/notifications.rb:123:in `instrument' actionpack (3.2.7) lib/action_controller/metal/instrumentation.rb:29:in `process_action' actionpack (3.2.7) lib/action_controller/metal/params_wrapper.rb:207:in `process_action' activerecord (3.2.7) lib/active_record/railties/controller_runtime.rb:18:in `process_action' actionpack (3.2.7) lib/abstract_controller/base.rb:121:in `process' actionpack (3.2.7) lib/abstract_controller/rendering.rb:45:in `process' actionpack (3.2.7) lib/action_controller/metal.rb:203:in `dispatch' actionpack (3.2.7) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch' actionpack (3.2.7) lib/action_controller/metal.rb:246:in `block in action' actionpack (3.2.7) lib/action_dispatch/routing/route_set.rb:73:in `call' actionpack (3.2.7) lib/action_dispatch/routing/route_set.rb:73:in `dispatch' actionpack (3.2.7) lib/action_dispatch/routing/route_set.rb:36:in `call' journey (1.0.4) lib/journey/router.rb:68:in `block in call' journey (1.0.4) lib/journey/router.rb:56:in `each' journey (1.0.4) lib/journey/router.rb:56:in `call' actionpack (3.2.7) lib/action_dispatch/routing/route_set.rb:600:in `call' actionpack (3.2.7) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call' rack (1.4.1) lib/rack/etag.rb:23:in `call' rack (1.4.1) lib/rack/conditionalget.rb:35:in `call' actionpack (3.2.7) lib/action_dispatch/middleware/head.rb:14:in `call' actionpack (3.2.7) lib/action_dispatch/middleware/params_parser.rb:21:in `call' actionpack (3.2.7) lib/action_dispatch/middleware/flash.rb:242:in `call' rack (1.4.1) lib/rack/session/abstract/id.rb:205:in `context' rack (1.4.1) lib/rack/session/abstract/id.rb:200:in `call' actionpack (3.2.7) lib/action_dispatch/middleware/cookies.rb:338:in `call' activerecord (3.2.7) lib/active_record/query_cache.rb:64:in `call' activerecord (3.2.7) lib/active_record/connection_adapters/abstract/connection_pool.rb:473:in `call' actionpack (3.2.7) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call' activesupport (3.2.7) lib/active_support/callbacks.rb:405:in `_run__122749671__call__530674861__callbacks' activesupport (3.2.7) lib/active_support/callbacks.rb:405:in `__run_callback' activesupport (3.2.7) lib/active_support/callbacks.rb:385:in `_run_call_callbacks' activesupport (3.2.7) lib/active_support/callbacks.rb:81:in `run_callbacks' actionpack (3.2.7) lib/action_dispatch/middleware/callbacks.rb:27:in `call' actionpack (3.2.7) lib/action_dispatch/middleware/reloader.rb:65:in `call' actionpack (3.2.7) lib/action_dispatch/middleware/remote_ip.rb:31:in `call' actionpack (3.2.7) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call' actionpack (3.2.7) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call' railties (3.2.7) lib/rails/rack/logger.rb:26:in `call_app' railties (3.2.7) lib/rails/rack/logger.rb:16:in `call' actionpack (3.2.7) lib/action_dispatch/middleware/request_id.rb:22:in `call' rack (1.4.1) lib/rack/methodoverride.rb:21:in `call' rack (1.4.1) lib/rack/runtime.rb:17:in `call' activesupport (3.2.7) lib/active_support/cache/strategy/local_cache.rb:72:in `call' rack (1.4.1) lib/rack/lock.rb:15:in `call' actionpack (3.2.7) lib/action_dispatch/middleware/static.rb:62:in `call' railties (3.2.7) lib/rails/engine.rb:479:in `call' railties (3.2.7) lib/rails/application.rb:220:in `call' rack (1.4.1) lib/rack/content_length.rb:14:in `call' railties (3.2.7) lib/rails/rack/log_tailer.rb:17:in `call' rack (1.4.1) lib/rack/handler/webrick.rb:59:in `service' C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `service' C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run' C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'
PhotographyController：
def create @photo = Photo.create(params[:photo]) end
最后，我的forms部分可能会有所帮助：
{ :controller => 'photography', :action => 'create'}, :html => { :multipart => true } do |f| %> prohibited this photo from being saved:
再次感谢。
我使用回形针遇到了这个错误以及其他类似的错误。 但我在Windows上运行我的开发环境，最新版本的paperclip使用`file’命令，windows似乎不太喜欢。
希望这很快就能解决，但是现在我通过使用最后一个有效的回形针版本回避了这个问题，即3.0.4。
如果您也在Windows上运行，只需将其添加到您的Gemfile：
gem 'paperclip', '3.0.4'
PS尝试在开发时使用3.0.4以及生产的最新版本可能是值得的。