Understanding Auth::check method - how it works under the hood - php

Question

I have created the following method in my admin controller:
public function index() {
// $recentBlogPost = DB::table('Admin')->get();
// Auth::logout();
if (!(Auth::check())) {
return Redirect::to('login');
}
$tags = DB::table('Tags')->get();
/* convert Object to array */
$tagsArray = array();
foreach($tags as $tag) {
$tagsArray[$tag->tag] = $tag->tag;
}
$tagsArray = json_decode(json_encode($tagsArray) , TRUE);
return view('admin.index')->with('tags' , $tagsArray);
}
Now i see the following line of code
(Auth::check())
I got this code from the laravel docs here ->https://laravel.com/docs/5.0/authentication
I would reallly like to know that that class or method is really doing under the hood , which file do i pull up for me to have a sneak peak to the code under the hood.

Answer 1

Auth::check()
// Illuminate\Auth\GuardHelpers
/**
* Determine if the current user is authenticated.
*
* #return bool
*/
public function check()
{
return ! is_null($this->user());
}
If you want to know $this->user():
// Illuminate\Auth\SessionGuard
/**
* Get the currently authenticated user.
*
* #return \Illuminate\Contracts\Auth\Authenticatable|null
*/
public function user()
{
if ($this->loggedOut) {
return;
}
// If we've already retrieved the user for the current request we can just
// return it back immediately. We do not want to fetch the user data on
// every call to this method because that would be tremendously slow.
if (! is_null($this->user)) {
return $this->user;
}
$id = $this->session->get($this->getName());
// First we will try to load the user using the identifier in the session if
// one exists. Otherwise we will check for a "remember me" cookie in this
// request, and if one exists, attempt to retrieve the user using that.
$user = null;
if (! is_null($id)) {
if ($user = $this->provider->retrieveById($id)) {
$this->fireAuthenticatedEvent($user);
}
}
// If the user is null, but we decrypt a "recaller" cookie we can attempt to
// pull the user data on that cookie which serves as a remember cookie on
// the application. Once we have a user we can return it to the caller.
$recaller = $this->getRecaller();
if (is_null($user) && ! is_null($recaller)) {
$user = $this->getUserByRecaller($recaller);
if ($user) {
$this->updateSession($user->getAuthIdentifier());
$this->fireLoginEvent($user, true);
}
}
return $this->user = $user;
}
How it happen?
You're using facade/helper - Illuminate\Support\Facades\Auth, but there are no check method.
Illuminate\Support\Facades\Auth extends Illuminate\Support\Facades\Facade
Illuminate\Support\Facades\Facade has a magic __callStatic() method
__callStatic execs check method on 'auth' instance
'auth' instance/singleton is registered in Illuminate\Auth\AuthServiceProvider::registerAuthenticator()
Ok, it means 'auth' instance is a 'Illuminate\Auth\AuthManager'
There is no 'check' method, but 'Illuminate\Auth\AuthManager' has a magic __call method
Illuminate\Auth\AuthManager::__call() execs 'check' method on 'guard' instance
Illuminate\Auth\AuthManager::guard() inits a guard according to your configs/auth.php
By default guard - session (Illuminate\Auth\SessionGuard)
Illuminate\Auth\SessionGuard does not have check method, but it uses Illuminate\Auth\GuardHelpers trait
Illuminate\Auth\GuardHelpers has check method
In other word Auth facade:
Execs facade methods
If facade method not found, execs Illuminate\Auth\AuthManager methods
If AuthManager method not found, execs guard(and guard trait) methods

Answer 2

To understand how it works it's better to look at the check() method source code:
public function check()
{
return ! is_null($this->user());
}
So it's just checking if user instance exists or not and returns true or false.