PHP best practices

Introduction

In this section we will list some of the best PHP practices you should consider adopting. PHP offers a lot of options and styles of writing your code. However, as your application grows and becomes more complex, following best practices is a must if you want modern and maintainable PHP code or simply want to be a better PHP developer.

PHP setup

PHP version

Use the latest stable PHP version (i.e., PHP 7.2 at the time of writing this). You will be able to use great new features and overall performance will be improved. Using old versions can lead to security issues.

PHP extensions

For performance and security reasons, a good practice is to disable extensions that you will not need in your production environment.

Coding style

Coding standards

Use PSR-1 and PSR-2 coding standards.

Arrays

Use short syntax for defining arrays:

$array = [
    "foo" => "bar",
    "bar" => "foo",
];

Ternary operator

In cases where you need to make a quick conditional check, there's a ternary operator that can make your code cleaner and more readable.

Let's assume you want to set the $discount based on the value of the $amount. If the $amount is less than 100, then the discount is 10%, and otherwise, it is 20%.

Say you want to check if the $amount variable equals 10, and if $amount equals 10 you want to set the $total to 1000, and if the $amount is NOT equal to 10 you want to set $total to 200.

You could use an if else statement:

<?php

if ($amount < 100) {
    $discount = 10;
} else {
    $discount = 20;
}

By using a ternary operator, you could write this in one line:

<?php

$discount = ($amount < 100) ? 10 : 20;

Note that in cases where you need to append a query if a certain condition is met, an if statement would be a better choice.

Composer

In modern PHP, we should write less code, and since many problems have already been solved, use existing solutions and libraries. Composer is a tool for managing your dependencies in a PHP project. By using a terminal, you can add, update, and remove dependent packages from packagist.org and other repositories. Composer uses a composer.json file, located in your project directory, for managing dependent packages.

Testing

Always test your code. If you're not familiar with concept of testing, start with PHPUnit.

Emails

For sending emails there are multiple options in PHP, from using PHP's default mail() function, to external third-party libraries such as Swift Mailer and PHPMailer. Try to avoid the default mail() function and instead use Swift Mailer or PHPMailer. Building modern contact forms, customizing headers, sending HTML emails, SMTP sending, different setups for sending emails in development environments, testing emails and other advanced functionalities are sort of a must these days, and the mail() function is too basic for that.

Passwords

Storing passwords must be done with PHP's built-in password hashing API.

Databases

For databases, using PDO or simply just an ORM is very convenient and can greatly help you handle advanced database manipulation tasks.

<?php
// PDO and MySQL example
$pdo = new PDO('mysql:host=localhost;dbname=database', 'user', 'password');
$statement = $pdo->query("SELECT id FROM friend");
$row = $statement->fetch(PDO::FETCH_ASSOC);
echo htmlentities($row['id']);

Security

Secured configuration files

Storing configuration files MUST be encapsulated.

return [
    # Database Configuration
    'database' => [
        'hostname' => 'localhost',
        'port' => 3306,
        'username' => 'someone',
        'password' => 'v3RyS3c|_|re'
    ],
];
<?php

$config = require __DIR__.'/relative/path/to/the/config.php';

Direct access to configuration files stored as formats such as JSON or YAML, for example, should always be restricted by .htaccess:

#Apache 2.4+
Require local

#Before Apache 2.4
Order Deny,Allow
Deny from all

For Nginx servers, where .htaccess files aren't used, the equivalent can be achieved by using your nginx.conf file:

location /foo/bar/config.yml {
   deny all;
}

When possible, for the best protection of configuration files, store them outside of the publicly available document root.

Documentation

Always maintain documentation for your code. It adds extra time to your work, but will be helpful to others (and also to you) in the future, to understand what you've written. We forget what certain functions, methods and parts of code do, so please always take extra time to document your work.

For inline PHP documentation, use phpDocumentor:

<?php

/**
 * Foo file description.
 */

/**
 * I belong to a class
 */
class Foo
{
}

Development environment

Don't pick a premade *AMP (MAMP/LAMP/WAMP/XAMPP) stack. Instead, use virtualization software like Vagrant or Docker. Vagrant helps you create and configure lightweight, reproducible, and portable development environments. When using virtualization, make sure to create a virtual machine that resembles the production server (the machine where you deploy). This will help you catch deployment issues during the development stage. These articles can help you get started with Vagrant and Docker in PHP development:

Since the information provided on the article page may be outdated, you should also refer to the official documentation for vagrant and docker, provided by the application vendor.



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Content of this work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) license. Code snippets in examples are published under the CC0 1.0 Universal (CC0 1.0). Thanks to all contributors.