app/controllers/devise/omniauth_callbacks_controller.rb in devise-3.5.10 vs app/controllers/devise/omniauth_callbacks_controller.rb in devise-4.0.0.rc1

@@ -1,7 +1,7 @@
 class Devise::OmniauthCallbacksController < DeviseController
-  prepend_before_filter { request.env["devise.skip_timeout"] = true }
+  prepend_before_action { request.env["devise.skip_timeout"] = true }
 
   def passthru
     render status: 404, text: "Not found. Authentication passthru."
   end
 
@@ -11,17 +11,17 @@
   end
 
   protected
 
   def failed_strategy
-    env["omniauth.error.strategy"]
+    request.respond_to?(:get_header) ? request.get_header("omniauth.error.strategy") : env["omniauth.error.strategy"]
   end
 
   def failure_message
-    exception = env["omniauth.error"]
+    exception = request.respond_to?(:get_header) ? request.get_header("omniauth.error") : env["omniauth.error"]
     error   = exception.error_reason if exception.respond_to?(:error_reason)
     error ||= exception.error        if exception.respond_to?(:error)
-    error ||= env["omniauth.error.type"].to_s
+    error ||= (request.respond_to?(:get_header) ? request.get_header("omniauth.error.type") : env["omniauth.error.type"]).to_s
     error.to_s.humanize if error
   end
 
   def after_omniauth_failure_path_for(scope)
     new_session_path(scope)