Displaying custom errors

In Yii, the error handling is very flexible, so you can create your own error handler for errors of a specific type. In this recipe, we will handle a 404 not found error in a smart way. We will show a custom 404 page that will suggest the content based on what was entered in the address bar.

Getting ready

1. Create a new yii2-app-basic application by using the Composer package manager, as described in the official guide at http://www.yiiframework.com/doc-2.0/guide-start-installation.html.
2. Add the fail action to your SiteController:

   class SiteController extends Controller
   {
       // …
   
       public function actionFail()
       {
           throw new ServerErrorHttpException('Error message example.');
       }
   }

3. Add the web/.htaccess file with the following content:

   RewriteEngine on
   RewriteCond %{REQUEST_FILENAME} !-f
   RewriteCond %{REQUEST_FILENAME} !-d
   RewriteRule . index.php

4. Configure pretty URLs for the urlManager component in your config/web.php file:

   'components...