How do I get the ID of the authenticated user using plain php

Depends if you use cookie or session. An example of checking a login

public function chklog()
    {
        if (Session::get('loggin') == false) {
            Url::redirect('admin');
        }
    }

Example from another framework. But you could google php login script and get some good ideas.

question updated

Look in the auth class source code. It uses plan php to keep tabs on the auth user.

@jekinney when I tried to go to auth definition this is the code I get.

<?php

namespace Illuminate\Support\Facades;

/**
 * @see \Illuminate\Auth\AuthManager
 * @see \Illuminate\Contracts\Auth\Factory
 * @see \Illuminate\Contracts\Auth\Guard
 * @see \Illuminate\Contracts\Auth\StatefulGuard
 */
class Auth extends Facade
{
    /**
     * Get the registered name of the component.
     *
     * @return string
     */
    protected static function getFacadeAccessor()
    {
        return 'auth';
    }
}

@Eco012390

https://laravel.com/api/5.2/Illuminate/Auth.html

The api docs with links to source code

This will work in plain PHP: auth()->user()->id

I believe this works also $request->user()

but I am concerned why you ask. If there is some reason you cannot use the facade then maybe you are hoping to get the authenticated user in some separate php file, ie, not part of the framework. If this is the case then you will be disappointed.

@Snapey yeah that's what I'm trying to do. my professor told me not to use any libraries in the algorithm i'm making for my newsfeed. so I was wondering how would I get the authenticated user ID without using any libraries.

Sorry, but the user only exists because the framework is bootstrapped when index.php is loaded.

PHP does not natively support the concept of a user, although of course it does support sessions.

Without a library, you would need to start sessions, receive the login form from the user, validate it then store the user identifier in the session.

Next time the user returns, get the id from the session storage.

You will need some pretty old tutorials to cover this without using a framework because in real life, noone codes this from the ground-up any more. This might give you an idea.. https://www.formget.com/login-form-in-php/

ROFLMAO :) @Eco012390 You need to pay more attention in your class :)

hahaha. @d3xt3r yeah I should start paying attention in my classes.