Koudoku 在本地运行良好，但在 Heroku 上崩溃

Question

我最近安装了Koudoku gem，它在我的计算机上运行良好，但是当我现在推送到 heroku 时，应用程序出现错误，日志如下所示。有谁知道为什么我收到有关 application_helper 的错误？我的项目中通常没有那个特定的文件，但我相信 Koudoku 引擎会在运行时添加它。感谢您的帮助！

编辑：我没有答案，但我怀疑这可能是由于引擎的初始化方式。我在 config/application.rb 文件中设置了以下行： config.assets.initialize_on_precompile = false 我认为这可能会阻止初始化程序加载，除非我根据这篇博文向我的 lib/engine.rb 添加一些内容： http://octothought.com/precompiling-assets-for-a-rails-engine-on-heroku/

谁能帮助我了解如何根据我的情况调整他们添加到 engine.rb 的代码？他们说：“神奇的咒语是将一个特殊的 :group => :assets 或 :group => :all 选项传递给引擎的初始化程序，并确保在该初始化程序中配置预编译。”但是在实际代码中，他们谈论的火箭发动机让我感到困惑。

initializer "RocketEngine asset precompile", :group => :all do |app|
  app.config.assets.precompile += %w(
    rocket.css 
    rocket.js
  )
end

这是我在 heroku 上的实际错误：

 heroku[web.1]: State changed from crashed to starting
 heroku[web.1]: Starting process with command `bin/rails server -p 54469 -e production`
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/actionpack-4.2.0.beta2/lib/abstract_controller/helpers.rb:144:in `modules_for_helpers'
 app[web.1]: => Booting WEBrick
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/bundler/gems/koudoku-9e73e64e5520/app/controllers/koudoku/application_controller.rb:4:in `<class:ApplicationController>'
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/railties-4.2.0.beta2/lib/rails/engine.rb:465:in `each'
 app[web.1]:    from /app/vendor/ruby-2.1.5/lib/ruby/2.1.0/tsort.rb:226:in `block in tsort_each'
 app[web.1]:    from /app/vendor/ruby-2.1.5/lib/ruby/2.1.0/tsort.rb:205:in `tsort_each'
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/activesupport-4.2.0.beta2/lib/active_support/dependencies.rb:308:in `depend_on'
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/railties-4.2.0.beta2/lib/rails/engine.rb:467:in `block in eager_load!'
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/rack-1.6.0/lib/rack/server.rb:208:in `app'
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/railties-4.2.0.beta2/lib/rails/commands/commands_tasks.rb:80:in `block in server'
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/railties-4.2.0.beta2/lib/rails/commands/commands_tasks.rb:75:in `tap'
 app[web.1]:    from bin/rails:8:in `<main>'
 app[web.1]: Exiting
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/actionpack-4.2.0.beta2/lib/abstract_controller/helpers.rb:148:in `block in modules_for_helpers'
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/activesupport-4.2.0.beta2/lib/active_support/dependencies.rb:248:in `require'
 app[web.1]:    from /app/config.ru:3:in `block in <main>'
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/railties-4.2.0.beta2/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
 app[web.1]:    from bin/rails:8:in `require'
 app[web.1]: => Run `rails server -h` for more startup options
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/actionpack-4.2.0.beta2/lib/abstract_controller/helpers.rb:108:in `helper'
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/activesupport-4.2.0.beta2/lib/active_support/dependencies.rb:349:in `require_or_load'
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/railties-4.2.0.beta2/lib/rails/engine.rb:465:in `eager_load!'
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/railties-4.2.0.beta2/lib/rails/application/finisher.rb:56:in `each'
 app[web.1]:    from /app/vendor/ruby-2.1.5/lib/ruby/2.1.0/tsort.rb:427:in `each_strongly_connected_component_from'
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/rack-1.6.0/lib/rack/builder.rb:49:in `eval'
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/rack-1.6.0/lib/rack/server.rb:336:in `wrapped_app'
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/railties-4.2.0.beta2/lib/rails/commands/server.rb:80:in `start'
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/railties-4.2.0.beta2/lib/rails/commands.rb:17:in `<top (required)>'
 app[web.1]: /app/vendor/bundle/ruby/2.1.0/gems/actionpack-4.2.0.beta2/lib/abstract_controller/helpers.rb:151:in `rescue in block in modules_for_helpers': Missing helper file helpers/application_helper.rb (AbstractController::Helpers::MissingHelperError)
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/actionpack-4.2.0.beta2/lib/action_controller/metal/helpers.rb:93:in `modules_for_helpers'
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/railties-4.2.0.beta2/lib/rails/initializable.rb:30:in `run'
 app[web.1]:    from /app/vendor/ruby-2.1.5/lib/ruby/2.1.0/tsort.rb:224:in `tsort_each'
 app[web.1]:    from /app/vendor/bundle/ruby/2.1.0/gems/activesupport-4.2.0.beta2/lib/active_support/dependencies.rb:248:in `block in require'

Answer 1

我通过将 application_helper.rb 添加到 app/helpers 来解决此问题：

module ApplicationHelper
end

同时在 controllers/application_controller.rb 中导入 ApplicationHelper

class ApplicationController < ActionController::Base
  protect_from_forgery with: :exception
  include ApplicationHelper
end