1 files changed, 15 insertions, 11 deletions
diff --git a/actionpack/lib/action_dispatch/middleware/request_id.rb b/actionpack/lib/action_dispatch/middleware/request_id.rb
index b9ca524309..805d3f2148 100644
--- a/actionpack/lib/action_dispatch/middleware/request_id.rb
+++ b/actionpack/lib/action_dispatch/middleware/request_id.rb
@@ -1,9 +1,12 @@
-require 'securerandom'
-require 'active_support/core_ext/string/access'
+# frozen_string_literal: true
+
+require "securerandom"
+require "active_support/core_ext/string/access"
 
 module ActionDispatch
-  # Makes a unique request id available to the action_dispatch.request_id env variable (which is then accessible through
-  # ActionDispatch::Request#uuid or the alias ActionDispatch::Request#request_id) and sends the same id to the client via the X-Request-Id header.
+  # Makes a unique request id available to the +action_dispatch.request_id+ env variable (which is then accessible
+  # through <tt>ActionDispatch::Request#request_id</tt> or the alias <tt>ActionDispatch::Request#uuid</tt>) and sends
+  # the same id to the client via the X-Request-Id header.
   #
   # The unique request id is either based on 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
@@ -12,23 +15,24 @@ module ActionDispatch
   # 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.
   class RequestId
-    X_REQUEST_ID = "X-Request-Id".freeze # :nodoc:
-    ACTION_DISPATCH_REQUEST_ID = "action_dispatch.request_id".freeze # :nodoc:
-    HTTP_X_REQUEST_ID = "HTTP_X_REQUEST_ID".freeze # :nodoc:
+    X_REQUEST_ID = "X-Request-Id".freeze #:nodoc:
 
     def initialize(app)
       @app = app
     end
 
     def call(env)
-      env[ACTION_DISPATCH_REQUEST_ID] = external_request_id(env) || internal_request_id
-      @app.call(env).tap { |_status, headers, _body| headers[X_REQUEST_ID] = env[ACTION_DISPATCH_REQUEST_ID] }
+      req = ActionDispatch::Request.new env
+      req.request_id = make_request_id(req.x_request_id)
+      @app.call(env).tap { |_status, headers, _body| headers[X_REQUEST_ID] = req.request_id }
     end
 
     private
-      def external_request_id(env)
-        if request_id = env[HTTP_X_REQUEST_ID].presence
+      def make_request_id(request_id)
+        if request_id.presence
           request_id.gsub(/[^\w\-]/, "".freeze).first(255)
+        else
+          internal_request_id
         end
       end