问题
When is the Rails request object available at the earliest time during the request lifecycle? Essentially, when is the request first available as a request object, and in which object? ActionDispatch?
Can you access request parameters from Tester::Application? If so, how? If not, what about using the environment? When is that information set?
回答1:
The Rack webserver creates the request object and then ActionDispatch inherits from it. So essentially, you'd be able to access the Rack::Request or ActionDispatch::Request objects within the middleware of the app.
Rack::Request
https://github.com/rack/rack/blob/master/lib/rack/request.rb
ActionDispatch::Request
https://github.com/rails/rails/blob/master/actionpack/lib/action_dispatch/http/request.rb
回答2:
A middleware is probably the best way to access this data. I made a simple gem for setting up a raw HTTP request/response log in Rails using the classes mentioned in the accepted answer.
https://github.com/andrhamm/marcopolo
来源：https://stackoverflow.com/questions/8422716/rails-how-do-you-access-the-raw-request-data-at-the-absolute-lowest-level