PHP is a popular general-purpose scripting language especially suited for web development. It is fast, flexible, and pragmatic, powering everything from blogs to the most popular websites in the world.
PHP Anti-Patterns Overview
PHP, despite its widespread use and continuous improvements, still has common anti-patterns that can lead to bugs, security vulnerabilities, and maintenance problems. Here are the most important anti-patterns to avoid when writing PHP code.
Using Loose Comparisons
PHP’s loose comparison (==
) can lead to unexpected results due to type juggling. Always use strict comparison (===
) to compare both value and type.
Not Sanitizing User Input
Always sanitize user input to prevent SQL injection, XSS, and other security vulnerabilities. Use prepared statements for database queries.
Using Deprecated mysql_ Functions
The mysql_*
functions are deprecated and removed in PHP 7+. Use mysqli_*
or PDO instead for database operations.
Not Using Namespaces
Use namespaces to organize your code and avoid naming conflicts, especially in larger applications.
Using eval()
Never use eval()
as it allows arbitrary code execution. Use safer alternatives specific to your use case.
Not Using Autoloading
Use Composer’s autoloading (PSR-4) instead of manual require
/include
statements to automatically load classes when needed.
Not Using Type Declarations
Use type declarations (scalar types, return types, nullable types) to make your code more robust and self-documenting.
Using Short Tags
Not Using Error Handling
Use proper error handling with try-catch blocks and exceptions to gracefully handle errors.
Using Superglobals Directly
Don’t use superglobals ($_GET
, $_POST
, etc.) directly. Validate and sanitize input or use a request abstraction.
Not Using Environment Variables
Don’t hardcode sensitive information like database credentials or API keys. Use environment variables or a .env
file (with proper security).
Not Using Dependency Injection
Use dependency injection to make your code more testable and flexible.
Not Using Interfaces
Use interfaces to define contracts and allow for different implementations.
Using Magic Methods Excessively
Magic methods (__get
, __set
, etc.) can make code harder to understand and debug. Use them sparingly and prefer explicit properties and methods.
Not Using Composer for Dependencies
Use Composer to manage dependencies instead of downloading libraries manually.
Not Using a Proper MVC Structure
Separate your code into Model (data), View (presentation), and Controller (logic) components.
Not Using PHP-FIG Standards
Follow PHP-FIG standards (PSR-1, PSR-2/PSR-12, etc.) for consistent, readable code.
Not Using Static Analysis Tools
Use static analysis tools like PHPStan, Psalm, or PHP_CodeSniffer to catch potential issues early.
Not Using Proper Session Management
Configure sessions securely to prevent session hijacking and other attacks.