Implementing your own smart 404 handler

In Yii, the error handling is very flexible, so you can create your own error handler for errors of specific types. 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. Set up a fresh Yii application by using yiic webapp as described in the official guide.

2. Configure a database and import the following SQL:

   CREATE TABLE `article` (
     `alias` varchar(255) NOT NULL,
     `title` varchar(255) NOT NULL,
     `text` text NOT NULL,
     PRIMARY KEY (`alias`)
   );

3. Generate an Article model using Gii.

4. Generate an Article crud using Gii.

5. Create the following articles:

   Title	Alias	Text
   Yii framework	yii-framework	Yii framework is good.
   Why Yii	why-yii	Why should I use Yii?
   PHP is a good tool	php-is-a-good-tool	PHP is nice!
   Yii as a tool for apps	yii-as-a-tool-for-apps	Yii is a good tool for apps.

How to do it...

Carry out the following...