How to Create and Publish a Composer Package for PHP

Step 1: Create Package Directory

In this step you create a directory to store your Composer package.

<code># Create a new directory for your package.
mkdir name-of-your-package
# Switch to that directory.
cd name-of-your-package
</code>

Initialize the Composer file with composer init and follow the prompts to set the package name, version, author, and description.

Package name

Package version

Package author

Package description

Step 2: Create Package Files

Create the source code for the package.

<code># Create the source code directory.
mkdir src
# Create a PHP file for the class.
touch src/HelloWorld.php
</code>

Edit src/HelloWorld.php and add the following class:

<code>&lt;?php

namespace YourVendor\HelloWorld;

class HelloWorld
{
    public function sayHello()
    {
        return 'Hello, World!';
    }
}
</code>

The class HelloWorld defines a sayHello() method that returns a simple greeting.

Step 3: Configure Autoloading

Add PSR‑4 autoloading information to composer.json so Composer can load classes from the src/ directory.

<code>{
    "autoload": {
        "psr-4": {
            "YourVendor\\HelloWorld\\": "src/"
        }
    },
    "prefer-stable": true,
    "minimum-stability": "dev"
}
</code>

Run composer dump-autoload to generate the autoload.php file containing the package’s autoload information.

Step 4: Write Tests

Create a tests directory and add a PHPUnit test for the package.

<code>mkdir tests
touch tests/HelloWorldTest.php
</code>

Edit tests/HelloWorldTest.php with the following content:

<code>&lt;?php

use YourVendor\HelloWorld\HelloWorld;
use PHPUnit\Framework\TestCase;

class HelloWorldTest extends TestCase
{
    public function testSayHello()
    {
        $helloWorld = new HelloWorld();
        $this->assertEquals('Hello, World!', $helloWorld->sayHello());
    }
}
</code>

Running the test should output OK (1 test, 1 assertion) .

Step 5: Publish the Package

To make the package available to others, publish it on Packagist . Ensure you have a Packagist account, then submit the repository.

After publishing, the package can be required in other projects with:

<code>composer require yourvendor/helloworld
</code>

Step 6: Local Testing in a Laravel Project

To test the package locally, add it as a path repository in your Laravel project's composer.json :

<code>{
    "repositories": [
        {
            "type": "path",
            "url": "/path/to/HelloWorld"
        }
    ],
    "require": {
        "yourvendor/helloworld": "*"
    }
}
</code>

Replace /path/to/HelloWorld with the actual path, then run composer update to install the package.

Use the package in Laravel code:

<code>&lt;?php

use YourVendor\HelloWorld\HelloWorld;

$helloWorld = new HelloWorld();
echo $helloWorld->sayHello();
</code>

This basic example helps you get started; more advanced features such as configuration files, views, or migrations can be added as needed.