Laravel Facades Part 1 – What they are and how they work

Facades allow us to call classes defined under the service container in an elegant and expressive way – as “static” interfaces. If you are a Laravel developer, chances are that you are using Facades all the time. You may not just know that yet. Laravel ships in with many facades like Hash, Input, Mail etc. Let’s take the example of Hash facade and try to figure out how it works.

You may be familiar with something like this,

Hash::make(‘password’);

If you search for a class named Hash, you won’t find it. Go to app/config.php and scroll down to the bottom where the class Aliases are defined. There you will see this,

 'Hash' => Illuminate\Support\Facades\Hash::class

Take a look at that file,

vendor\laravel\framework\src\Illuminate\Support\Facades\Hash.php

This file has just one method in it,

protected static function getFacadeAccessor()
{
return 'hash';
}

Go back to the app/config.php file again and take a look at the providers list, you can see that a Service provider has been added for Hashing

 Illuminate\Hashing\HashServiceProvider::class

Take a look at the service provider under vendor\laravel\framework\src\Illuminate\Hashing\HashServiceProvider.php
You will see this under the register method,

$this->app->singleton('hash', function () {
return new BcryptHasher;
});

It defines that the class BcryptHasher is associated with the hash facade ( the value returned by the getFacadeAccessor method in the Hash Facade file we saw above). Let’s try to find that class

You can see it here

vendor\laravel\framework\src\Illuminate\Hashing\BcryptHasher.php

But wait, the make method is not static but we are able to call it like

Hash::make(‘password’)

Underneath the hood, Laravel makes use of the callStatic magic method and reflection to make this happen. You can read through those if you are not familiar with the terms
http://php.net/manual/en/language.oop5.overloading.php#object.callstatic

What is Reflection in PHP?

Let’s continue digging in. The BcryptHasher implements HasherContract. Its imported at the top of the file,

use Illuminate\Contracts\Hashing\Hasher as HasherContract;

It’s a nice and clean interface that defines the contract which means every one of its implementations that should satisfy this contract.

Suppose you wish to implement your own hashing function or change the existing Bcrypter class. Just go to the HashServiceProvider and change the class there,

$this->app->singleton('hash', function () {

            return new CustomHasher;

        });

Clean and simple! The very reason we all love Laravel.

As you can see Facades are great if you know how to use them. You have an elegant syntax and flexibility while not compromising on anything. In part 2, we will learn how to create your own custom Facades.