Class: ActionDispatch::RequestId

Inherits:
Object
  • Object
show all
Defined in:
actionpack/lib/action_dispatch/middleware/request_id.rb

Overview

Makes a unique request id available to the action_dispatch.request_id env variable (which is then accessible through ActionDispatch::Request#uuid) and sends the same id to the client via the X-Request-Id header.

The unique request id is either based off the X-Request-Id header in the request, which would typically be generated by a firewall, load balancer, or the web server, or, if this header is not available, a random uuid. If the header is accepted from the outside world, we sanitize it to a max of 255 chars and alphanumeric and dashes only.

The unique request id can be used to trace a request end-to-end and would typically end up being part of log files from multiple pieces of the stack.

Instance Method Summary collapse

Constructor Details

#initialize(app) ⇒ RequestId

Returns a new instance of RequestId.



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# File 'actionpack/lib/action_dispatch/middleware/request_id.rb', line 16

def initialize(app)
  @app = app
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'actionpack/lib/action_dispatch/middleware/request_id.rb', line 20

def call(env)
  env["action_dispatch.request_id"] = external_request_id(env) || internal_request_id
  status, headers, body = @app.call(env)

  headers["X-Request-Id"] = env["action_dispatch.request_id"]
  [ status, headers, body ]
end