Pro PHP- Patterns, Frameworks, Testing and More

CHAPTER 16 ■ ADVANCED ZEND FRAMEWORK^239

Next, you will need to determine why the exception was thrown. The error information is

contained in the request parameter 'error_handler' and can be fetched as shown in Listing 16-5.

Listing 16-5. Fetching Error Information (ErrorController.php)

<?php

class ErrorController extends Zend_Controller_Action {

public function errorAction() {

$request = $this->getRequest();

$errorHandler = $request->getParam('error_handler');

Zend_Debug::dump($errorHandler);

}

}

Finally set the throwExceptions() call in your bootstrap file to false, or simply remove the

entire line to re-enable the default behavior.

Now, if you generate an error, such as by visiting a nonexistent URL, you will get pages of

information about the error.

The error controller is not intended to catch all errors, like syntax errors, but it will do a

reasonably good job of catching any exception that occurs within your action controller’s

execution.

Application Logging

Zend_Log allows your applications to generate and record information about their operation.

This information can be integrated with error handling or used to generate debugging infor-

mation about operational parameters.

Zend_Log has four architectural parts:

Logs: These are the responsible objects, where you will call methods to add messages to

the log. They are responsible because they are where the other components tie in.

Writers: These allow you to record the data in a log to a variety of output formats— from

files and streams to a database when integrated with Zend_Db. I recommend using files

over recording events to a database, as database logging can make debugging a database

connection failure much more difficult.

Formatters: These are used to take the Zend_Log data and turn it into a specific format.

They are required because, by default, Zend_Log data is stored in an array format. Formatters

take this array form and turn it into a string for logging.

Filters: These allow you to control which error messages will be logged by defining a priority

threshold for your application. You may want to integrate the filter threshold with your

Zend_Config file.

These four components work together to provide a very powerful set of logging options. To

demonstrate the logging functionality, let’s look at how you can integrate the ErrorController

McArthur_819-9C16.fm Page 239 Friday, February 29, 2008 5:07 PM