PHP: How to manage errors gracefully?

Question

When failed to access something on the web (api, database), how would I stop executing the rest of the script and log the error in the log file? Well, and so that the visito

Answer 1

I generally like using Exceptions, in that kind of situation : it allows me to have all error-handling code at one place.

For instance, I'd use something a bit like this :

try {
    // Some code

    // Some code that throws an exception

    // Some other code -- will not be executed when there's been an Exception

} catch (Exception $e) {
    // Log the technical error to file / database

    // Display a nice error message
}

With that, all error-handling code is in the catch block -- and not scatterred accros my whole application.

Note, though, that many PHP functions don't throw exceptions, and only raise a warning or an error...

For those, you could use set_error_handler to define your own error handler -- which could throw an Exception ;-)
For instance, see the example on the manual page of ErrorException.

Although this will work real fine for many errors/warnings, you should note that it will not work for Parse Error nor Fatal Error :

• The first kind are actually raised before the PHP code is actually executed
• And the second kind are... well... Fatal.

And I would never place any die nor exit in the middle of my code : that's, in my opinion, one of the worst possible way of dealing with errors.

I would also configure my server / application so :

• Error messages are not displayed in the output, setting display_errors to Off.
• Errors are logged to a file, using log_errors and error_log.