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PHP

Every dynamic page a LAMP server produces passes through PHP. Linux keeps the processes alive, Apache 129 accepts the connection and MySQL 524 holds the rows, but the decision about what a visitor actually sees (which products, in what order, whether the login worked, what the error says) is made by a few hundred lines of PHP that run, print and forget on every request.

PHP has changed more in the last decade than its reputation suggests. The language you will write here has strict types, enums, readonly classes, property hooks, first-class callables, attributes, a pipe operator and a JIT compiler. Much of the PHP 5 code in old tutorials no longer runs at all: mysql_*, each(), create_function() and mcrypt are gone. Every example in this chapter is written for PHP 8.5, the current stable series, and was run on PHP 8.5 before its output was printed. Where a feature arrived in an earlier release, the text says so, so you know what an older server can use.

The chapter moves from the engine outward. It starts with how PHP sits behind Apache and how a request becomes a page, then covers the language itself: types, operators, functions, arrays, strings, dates, files and the object model through interfaces, traits, generators, enums and attributes. From there it turns to the work a web application does: Composer 5,243 and autoloading, error handling and logging, forms and validation, sessions and uploads, database access with PDO and prepared statements, security, JSON and HTTP APIs, and email and images. It finishes with the tools that keep code honest in production: PHPUnit 79,198 , debugging and static analysis, OPcache and PHP-FPM tuning, and asynchronous PHP.

MySQL taught the SQL, so the database sections here cover only the PHP side of the conversation. Laravel builds on all of it with Laravel 2,157 , which is PHP code organized by conventions: everything you learn here is what runs underneath.

What you will learn

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