Score:1

Drupal

Ajax form inside custom system.404 route controller doesn't work

Chris Roditis

12/2/22, 6:36 PM

I need to display custom logic in 404 pages so I have overridden the route controller of the system.404 route like this:

class RouteSubscriber extends RouteSubscriberBase {

  protected function alterRoutes(RouteCollection $collection) {
    if ($route = $collection->get('system.404')) {
      $route->setDefault('_controller', '\Drupal\mymodule\Controller\myController::on404');
    }
  }
}

So let's say I am currently at the path /non-existing-path and the on404 callback renders my custom content just fine. Problem is I am also rendering a form that contains an Ajax element (a button), which doesn't work because apparently the Ajax request is made towards the following path:

/system/404?q=non-existing-path&destination=non-existing-path&_exception_statuscode=404&ajax_form=1&_wrapper_format=drupal_ajax

which, not unexpectedly, returns a Status Code: 404 Not Found

What am I missing?

So far I've tried intercepting the NotFoundHttpException with my own listener and changing it to a HttpException(200) in hopes I could turn a 404 page into a 200 but I am at a loss after that and it seems like an overkill.

1 + 7

ajax

4uk4

12/3/22, 6:34 AM

If you want to try to change the 404 to a 200 set a redirect response in the event listener.

Chris Roditis

12/3/22, 10:30 AM

thanks but this will redirect me to another path, I want to stay at the current path (that doesn't exist) and render my content together with the ajax form

4uk4

12/3/22, 11:32 AM

OK, then I misread your last sentence. Concerning the main topic. `/system/404` doesn't return a 404 status code when used outside of an exception. It returns the content of system.404 in a 200 response and it works with Ajax. Just tested it by setting a form as 404 content.

Chris Roditis

12/3/22, 10:30 PM

Thanks for looking into it but to make it more clear, I am trying to render a form (with an ajax button in it), in the default 404 page. So whenever someone hits a non existent page, the "Page not found" message appears and below it the form. Problem is the ajax button doesnt work.

4uk4

12/4/22, 6:17 AM

As explained, I can't reproduce the issue. The system/404 route returns a 200 (not a 404 as you've mentioned) and Ajax actions over this route work without problems in my tests with two different forms, a custom form and a core form (node edit form).

Chris Roditis

12/4/22, 8:17 AM

The path Im concerned with is not system/404, but any random non-existent path. Therefore I'm concerned with the call of the 'system.404' route *within* the NotFoundHttpException exception, not outside of one. Only when a 404 Not found is thrown.

4uk4

12/4/22, 9:06 AM

I have placed both test forms in a 404 of a random non-existent path as well. Cause for concern are the subsequent requests for system/404, which in my case return a status code 200 and in your case a status code 404, which I can't reproduce.

Score:0

Drupal

4uk4

12/4/22, 12:22 PM

Ajax form inside custom system.404 route controller does work

For example a node form returned from the controller:

<?php

namespace Drupal\mymodule\Controller;    

use Drupal\node\Entity\Node;

class MyController extends ControllerBase {

  public function on404() {
    $node = Node::create(['type' => 'article']);
    return $this->entityFormBuilder()->getForm($node);
  }

}

The node form is fully functional including complex Ajax operations like opening the media browser.

Status code 404 or 200

Problem is I am also rendering a form that contains an Ajax element (a button), which doesn't work because apparently the Ajax request is made towards the following path:

/system/404?q=non-existing-path&destination=non-existing-path&_exception_statuscode=404&ajax_form=1&_wrapper_format=drupal_ajax

which, not unexpectedly, returns a Status Code: 404 Not Found

This is not true, a request for /system/404 returns a 200 status code when called outside of an exception handler, for example in an ajax request. The system.404 route is a normal route which is executed by the exception handler in a sub-request. The 404 status is added later and not part of this route.

0 + 1

Chris Roditis

12/4/22, 8:56 PM

"The system.404 route is a normal route which is executed by the exception handler in a sub-request" this helped point me in the right direction. Thanks for all the help!

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