PSR-1: Basic Coding Standard in PHP

Ever wondered why some PHP codebases are a joy to work with while others feel like a maze? A lot of it comes down to following consistent coding standards. Let’s explore PSR-1, the foundation of modern PHP development that helps teams write cleaner, more maintainable code!

Overview of PSR-1 Rules

1. Files and Namespaces

• Files MUST use only <?php and <?= tags
• Files MUST use only UTF-8 without BOM for PHP code
• Files SHOULD either declare symbols (classes, functions, constants) OR cause side-effects (generate output, modify settings, etc.) but SHOULD NOT do both

2. Namespace and Class Names

• Classes MUST be declared in StudlyCaps
• Class constants MUST be declared in all upper case with underscore separators

3. Class Methods

• Method names MUST be declared in camelCase

Practical Implementation

Let’s look at a correct PSR-1 implementation from our example repository:

<?php

namespace JonesRussell\PhpFigGuide\PSR1;

class UserManager
{
    const VERSION = '1.0.0';
    const ERROR_TYPE_NOT_FOUND = 'not_found';

    public function getUserById($id)
    {
        // Implementation
        return ['id' => $id, 'name' => 'John Doe'];
    }
}

This example demonstrates:

• Proper namespace declaration using StudlyCaps
• Class name in StudlyCaps
• Constants in uppercase with underscores
• Method name in camelCase

Common Violations and Fixes

1. Mixed Responsibilities

2. Incorrect Naming

Integration with Modern PHP Tools

Our example repository includes setup for:

• PHP_CodeSniffer for PSR-1 validation (composer check-style)
• Automated style fixing (composer fix-style)
• PHPUnit for testing implementations
• Composer autoloading following PSR-4

Next Steps

In our next post, we’ll explore PSR-12, which extends these basic coding standards with more comprehensive style guidelines. This post is part of our PSR Standards in PHP series.

Resources

• Official PSR-1 Specification
• PHP_CodeSniffer PSR-1 Ruleset
• Series Example Repository (v0.1.0 - PSR-1 Implementation)