What is a Namespace in PHP?

A namespace in PHP is a way to group related code and avoid name conflicts between classes, functions, or constants.

Why Do We Need Namespaces?

magine you're working on a large project (like Drupal) with hundreds of modules. What happens if two modules define a class called UserController?

Without namespaces, PHP wouldn't know which one you're referring to—leading to fatal errors.

Namespaces Solve This Problem

Namespaces work like folders in your file system:

// File: modules/custom/my_module/src/Controller/MyController.php
namespace Drupal\my_module\Controller;

class MyController {
// Your controller code here
}

In this case, even if another module has a class called MyController, it won't clash because it's in a different namespace.

Analogy

Think of namespaces like:

Email addresses: You can have john@gmail.com and john@yahoo.com — the usernames are the same, but the domain keeps them separate.
Folders: You can have a file named invoice.pdf in multiple folders. As long as they’re in different folders, they don’t conflict.

PHP Namespace Syntax

Here's a basic syntax:

<?php
namespace MyProject\SubNamespace;

class MyClass {
public function sayHello() {
return "Hello from MyClass!";
}
}

To use this class somewhere else:

use MyProject\SubNamespace\MyClass;

$obj = new MyClass();
echo $obj->sayHello();

Namespaces in Drupal

Drupal follows the PSR-4 autoloading standard, which means:

The namespace matches the folder structure.
Drupal automatically loads classes based on their namespace.

Example:

namespace Drupal\my_module\Controller;

use Drupal\Core\Controller\ControllerBase;

class MyController extends ControllerBase {
public function content() {
return ['#markup' => 'Hello Drupal with namespaces!'];
}
}

Key Takeaways

Namespaces prevent naming conflicts.
They group related code logically.
In Drupal, they follow the Drupal\module_name\SubFolder structure.
Understanding them is essential for writing modern Drupal code.

Why Do We Need Namespaces?

Namespaces Solve This Problem

Analogy

PHP Namespace Syntax

Namespaces in Drupal

Key Takeaways

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