ruby-on-rails - 我如何从 Rails 中访问 Rack 环境？

Question

我有一个看起来像这样的 Rack 应用程序:

class Foo
  def initialize(app)
    @app = app
  end
  def call(env)
    env["hello"] = "world"
    @app.call(env)
  end
end

在将我的 Rack 应用程序挂接到 Rails 之后，如何从 Rails 中访问 env["hello"]？

更新:感谢 Gaius 的回答。 Rack and Rails 允许您在请求期间或 session 期间存储内容:

# in middleware
def call(env)
  Rack::Request.new(env)["foo"] = "bar"  # sticks around for one request

  env["rack.session"] ||= {}
  env["rack.session"]["hello"] = "world" # sticks around for duration of session
end

# in Rails
def index
  if params["foo"] == "bar"
    ...
  end
  if session["hello"] == "world"
    ...
  end
end

Answer 1

我很确定您可以使用 Rack::Request 对象来传递请求范围的变量:

# middleware:
def call(env)
  request = Rack::Request.new(env) # no matter how many times you do 'new' you always get the same object
  request[:foo] = 'bar'
  @app.call(env)
end

# Controller:
def index
  if params[:foo] == 'bar'
    ...
  end
end

或者，您可以直接获取“env”对象:

# middleware:
def call(env)
  env['foo'] = 'bar'
  @app.call(env)
end

# controller:
def index
  if request.env['foo'] == 'bar'
    ...
  end
end