Drupal 8 module routing page not found?

Question

I have a simple question, I want Drupal to route this page but keep getting this error:

"The website encountered an unexpected error. Please try again later."

The drupal error log displays this :

"InvalidArgumentException: Class "\Drupal\dblogin\Controller\DbloginController::reddb" does not exist. in Drupal\Core\DependencyInjection\ClassResolver->getInstanceFromDefinition() (line 24 of C:\drupal_sites\drupal-8.6.2\core\lib\Drupal\Core\DependencyInjection\ClassResolver.php)."

The code I have implemented for this is:

dblogin.reddb:
  path: /admin/reddb
  defaults:
    _title: 'DBlogin'
    _form: '\Drupal\dblogin\Controller\DbloginController::reddb'
  requirements:
    _permission: 'access content'

and in \\src\\Controller\\DbloginController.php

<?php
namespace Drupal\dblogin\Controller;
use Drupal\Core\Controller\ControllerBase;

class dbloginController extends ControllerBase {

public function reddb() {
      $build = [
        '#markup' => $this->t('DB Login'),
      ];
      return $build;
}
/**
 * replacement process callbacks.
 */
}
?>

I have also tried to just make it return "hello", but to no avail.

<?php
namespace Drupal\dblogin\Controller;
use Drupal\Core\Controller\ControllerBase;

class dbloginController extends ControllerBase {

    public function reddb() {
        return "hello";
    }
    /**
       * replacement process callbacks.
    */
}
?>

Could anyone help me out here? Thanks in advance!

Answer 1

Name of class should same in routing and controller file. You should make changes in code like

<?php
namespace Drupal\dblogin\Controller;
use Drupal\Core\Controller\ControllerBase;

class DbloginController extends ControllerBase {

    public function reddb() {
        return "hello";
    }
    /**
       * replacement process callbacks.
    */
}
?>

in routing.

  requirements:
    _permission: 'administer site configuration'

Answer 2

There are two Issues with your module which I can see from code.

1) In your routing file. Please replace your code with below lines.

dblogin.reddb:
  path: '/admin/reddb'
  defaults:
    _title: 'DBlogin'
    _form: '\Drupal\dblogin\Controller\DbloginController::reddb'
  requirements:
    _permission: 'access content'

2) In your controller. The file name and classname of your controller should be same everytime. So you controller code would be.

<?php
namespace Drupal\dblogin\Controller;
use Drupal\Core\Controller\ControllerBase;

class DbloginController extends ControllerBase {

public function reddb() {
      $build = [
        '#markup' => $this->t('DB Login'),
      ];
      return $build;
}
/**
 * replacement process callbacks.
 */
}
?>

Answer 3

error:

_form: '\Drupal\dblogin\Controller\DbloginController::reddb'

It must be:

_controller: '\Drupal\dblogin\Controller\DbloginController::reddb'