What's the most common pattern for error handling you see in beginner's PHP code? - That's right, do_X() or die('do_X failed);. That's nice and all, as at least you have some sort of error handling, but I think this way of handling errors must go. There is no place for it in modern PHP code - it's the worst way to handle errors, not much better than not handling them at all.

He talks about why die() is so bad and some alternatives to it - trigger_error (with a custom error handler) and exceptions. When used correctly, these two can help your script correctly catch and handle errors without the mess of a die().

I see it all the time, and I see people telling other people to do that all the time. It's plain simply bad practice and it's time that people start to understand this. When I confront people with it they usually say something along the lines of "oh, but it's just for debugging purposes". Okay, so I tend to put echo and var_dump() statements in my code for debugging as well. However, this is not the same.

They list several reasons why the "or die trick" is a bad idea including the non-catchable error that's thrown and that there's no control over where the error message from die goes. As a better alternative, they suggest using trigger_error and the exception handling built into PHP5 to correctly catch any potential errors a statement might throw.

Now, I have no actual authority to do so. My PHP CVS karma does not extend that far. And I doubt it will actually get removed despite it being nothing more than an alias for exit now. No, what I would like to call a death to is the usage of die such as [echoing out a message to the user instead of doing proper error handling].

He points out a few perfectly viable alternatives like the exception handlers, the trigger_error function and custom error handlers.

Scripts tend to die, and that's not usually nice. We do not want to show the user a fatal error nor a blank page (display errors off) . PHP has a function called register_shutdown_function which lets us set up a function which is called at execution shutdown. What this means is that our function will be executed when our script is done executing / dying and PHP execution is about to shut down.

He suggests various things that can be done with the functionality, including checking for successful script execution (via a false variable that can be checked for success).

Since error handling is something that you should introduce (at least progressively) into your applications, in this article I'll explore some of the most common error checking methods available in PHP, in order to make web applications much more robust and reliable.

The end result of this experience will be an illustrative list of hands-on examples that utilize different error handling methods, ranging in from using simple "die()" statements, to manipulating errors within an object-oriented context, by utilizing exceptions.

They cover things like the basic die() statement, triggering errors in your code with the trigger_error() function, using the error handling in PEAR, and setting boolean flags to catch when things go wrong...]]> Thu, 12 Jan 2006 06:34:19 -0600