带有导轨的Hello World机架中间件3:如何处理所有请求的主体 [英] Hello World rack middleware with rails 3: how to process body of all requests

问题描述

我想尝试一个简单的机架中间件"hello world"，但是我似乎陷入了困境. 似乎主要语法已更改，因为某些示例使用了以下代码:

i want to try out a simple rack middleware "hello world", but i seem to get stuck. it looks like the main sytax changed, since some examples use this code:

require 'rack/utils'

class FooBar

  def initialize(app)
    @app = app
  end

  def call(env)
    status, headers, body = @app.call(env)
         body.body << "\nHi from #{self.class}"
         [status, headers, body]
  end
end

产生错误:

undefined method `<<' for #<ActionDispatch::Response:0x103f07c48>

即使我查看那里的其他代码，我似乎也无法使它们在rails 3.0.3下运行.

even when i look at other codes out there, i cannot seem to get them running with rails 3.0.3.

这是我的具体问题:

• 我如何获得一个简单的机架中间件来运行和修改Rails应用程序的任何输出内容?
• 我应该在哪里放置Rails.application.config.middleware.use声明? (我为此在config/initializers中创建了自己的初始化程序)

非常感谢！

推荐答案

Rails 3.2.12 + :

上一个答案不适用于Rails 3.2.12 +

previous answer does not work for Rails 3.2.12+

这个做:

# in config/application.rb
config.middleware.use 'FooBar'

# in config/initializers/foo_bar.rb
class FooBar
  def initialize(app)
    @app = app
  end

  def call(env)
    status, headers, response = @app.call(env)
    response.body += "\nHi from #{self.class}"
    # response.body << "..." WILL NOT WORK
    [status, headers, response]
  end
end

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