Lesson 18 - Exceptions in PHP

In the previous lesson, Guestbook in PHP - continuation, we finished making a simple guestbook with modular captchas using interfaces. Today, we are going to dive deeper into the world of object-oriented programming by learning about exceptions. This is the last major construct that we hadn't discussed yet (every programmer should know about exceptions).

Exceptions

An exception could simply be described as a runtime error. A perfect textbook example would be dividing by zero or reading a non-existent file. Exceptions mostly occur when a user enters invalid input.

Modern programming languages use exceptions whenever something goes wrong. Unfortunately, PHP has a different and older non-object-oriented system for handling errors, called ErrorReporting. You all have definitely are aware of it at this point. When something goes wrong, PHP writes a notice, warning or fatal error (if the error was really serious).

Going over exceptions in PHP is kind of weird knowing that PHP itself doesn't use them much Some of its functions return false in case of failure, while others cause errors. Only the most modern ones throw exceptions.

Exceptions are an object-oriented way to deal with runtime errors, so we should definitely use them in our applications. The main reason being that they simplify and clarify our applications (like most object-oriented constructs). We are going to continue using them in the proceeding PHP courses.

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