使用「rails生成腳手架」時出現NoMethodError

Question

我正在使用nitrous.io關注Michael Hartl的Ruby on Rails教程。現在我正在嘗試使用scaffold命令，它返回一個NoMethodError。我很新的編碼，所以我不知道錯誤的原因，但這裏正是發生的事情：

~/workspace/rails_projects/demo_app(master)$ rails generate scaffold User name:string email:string 
/home/action/workspace/rails_projects/demo_app/config/environments/development.rb:1:in `<top (required)>': undefined method `configure' for #<DemoAppp::Application:0x007fa3572a63e8> (NoMethodError) 
     from /home/action/.gem/ruby/2.1.1/gems/activesupport-4.0.5/lib/active_support/dependencies.rb:229:in `require' 
     from /home/action/.gem/ruby/2.1.1/gems/activesupport-4.0.5/lib/active_support/dependencies.rb:229:in `block in require' 
     from /home/action/.gem/ruby/2.1.1/gems/activesupport-4.0.5/lib/active_support/dependencies.rb:214:in `load_dependency' 
     from /home/action/.gem/ruby/2.1.1/gems/activesupport-4.0.5/lib/active_support/dependencies.rb:229:in `require' 
     from /home/action/.gem/ruby/2.1.1/gems/railties-4.0.5/lib/rails/engine.rb:591:in `block (2 levels) in <class:Engine>' 
     from /home/action/.gem/ruby/2.1.1/gems/railties-4.0.5/lib/rails/engine.rb:590:in `each' 
     from /home/action/.gem/ruby/2.1.1/gems/railties-4.0.5/lib/rails/engine.rb:590:in `block in <class:Engine>' 
     from /home/action/.gem/ruby/2.1.1/gems/railties-4.0.5/lib/rails/initializable.rb:30:in `instance_exec' 
     from /home/action/.gem/ruby/2.1.1/gems/railties-4.0.5/lib/rails/initializable.rb:30:in `run' 
     from /home/action/.gem/ruby/2.1.1/gems/railties-4.0.5/lib/rails/initializable.rb:55:in `block in run_initializers' 
     from /home/action/.parts/packages/ruby2.1/2.1.1/lib/ruby/2.1.0/tsort.rb:226:in `block in tsort_each' 
     from /home/action/.parts/packages/ruby2.1/2.1.1/lib/ruby/2.1.0/tsort.rb:348:in `block (2 levels) in each_strongly_connected_component' 
     from /home/action/.parts/packages/ruby2.1/2.1.1/lib/ruby/2.1.0/tsort.rb:418:in `block (2 levels) in each_strongly_connected_component_from' 
     from /home/action/.parts/packages/ruby2.1/2.1.1/lib/ruby/2.1.0/tsort.rb:427:in `each_strongly_connected_component_from' 
     from /home/action/.parts/packages/ruby2.1/2.1.1/lib/ruby/2.1.0/tsort.rb:417:in `block in each_strongly_connected_component_from' 
     from /home/action/.gem/ruby/2.1.1/gems/railties-4.0.5/lib/rails/initializable.rb:44:in `each' 
     from /home/action/.gem/ruby/2.1.1/gems/railties-4.0.5/lib/rails/initializable.rb:44:in `tsort_each_child' 
     from /home/action/.parts/packages/ruby2.1/2.1.1/lib/ruby/2.1.0/tsort.rb:411:in `call' 
     from /home/action/.parts/packages/ruby2.1/2.1.1/lib/ruby/2.1.0/tsort.rb:411:in `each_strongly_connected_component_from' 
     from /home/action/.parts/packages/ruby2.1/2.1.1/lib/ruby/2.1.0/tsort.rb:347:in `block in each_strongly_connected_component' 
     from /home/action/.parts/packages/ruby2.1/2.1.1/lib/ruby/2.1.0/tsort.rb:345:in `each' 
     from /home/action/.parts/packages/ruby2.1/2.1.1/lib/ruby/2.1.0/tsort.rb:345:in `call' 
     from /home/action/.parts/packages/ruby2.1/2.1.1/lib/ruby/2.1.0/tsort.rb:345:in `each_strongly_connected_component' 
     from /home/action/.parts/packages/ruby2.1/2.1.1/lib/ruby/2.1.0/tsort.rb:224:in `tsort_each' 
     from /home/action/.parts/packages/ruby2.1/2.1.1/lib/ruby/2.1.0/tsort.rb:205:in `tsort_each' 
     from /home/action/.gem/ruby/2.1.1/gems/railties-4.0.5/lib/rails/initializable.rb:54:in `run_initializers' 
     from /home/action/.gem/ruby/2.1.1/gems/railties-4.0.5/lib/rails/application.rb:215:in `initialize!' 
     from /home/action/workspace/rails_projects/demo_app/config/environment.rb:5:in `<top (required)>' 
     from /home/action/.gem/ruby/2.1.1/gems/railties-4.0.5/lib/rails/application.rb:189:in `require' 
     from /home/action/.gem/ruby/2.1.1/gems/railties-4.0.5/lib/rails/application.rb:189:in `require_environment!' 
     from /home/action/.gem/ruby/2.1.1/gems/railties-4.0.5/lib/rails/commands.rb:44:in `<top (required)>' 
     from bin/rails:8:in `require' 
     from bin/rails:8:in `<main>' 

對我來說，似乎是出於某種原因對development.rb的路徑是不正確的一個，但我只是猜測。

Answer 1

這可能是由於環境中的命名空間問題導致的。你的應用程序被稱爲DemoAppp（注意「P」上），因此請確保您的命名約定遵循以下幾點：

# app/config/initializers/development.rb 
DemoAppp::Application.configure do 

或者，如果它可能是DemoAppp是一個拼寫錯誤，你可以想要用DemoApp替換DemoAppp與兩個「p」s。