Using psr-4 standard in composer autoload to implement class namespace

13/10/2017 - PHP

This application shows us how to implement PSR-4 standard in order to use a common "namespace" for all our classes in our application.


composer.json


{
  "autoload": {
    "psr-4": {
      "Application\\": "src/Application/"
    }
  }
}

Any class located under src/Application/ folder or sub folders, will use Application namespace like shown below.


# src/Application/ClassOne.php

<?php

namespace Application;

class ClassOne
{
    ...
}

# src/Application/Service/ClassTwo.php

<?php

namespace Application\Service;

class ClassTwo
{
    ...
}

Our application structure looks like below.


| root/
|   - src/
|     - Application/      # namespace itself
|       - Service/
|           ClassOne.php  # namespace Application\Service
|         ClassTwo.php    # namespace Application
|   composer.json