discord/connect_discord_oauth.php

<?php
// get current url
$current_url = $_SERVER['REQUEST_URI'];

// if user is currently on registration page
if (strpos($current_url, 'registration') !== false) {

    // require proper directory for config.php
    require_once 'models/config.php';

// if user is not on registration page...
} else {

    // require proper directory for config.php
    require_once '../models/config.php';

}

// require other necessary files;
require $DBphp_location;
require 'discord_oauth.php';

$redirectURL = $discord_redirect_url; //The URL that the user will be redirect back too
$clientID = 'xxx';                              //The ID of the client
$clientSecret = 'xxx';            //The sensitive and secret key of the client
$scope = 'identify email';


function getUserId($code) {
    require '../models/config.php';
    $redirectURL = $discord_redirect_url; //The URL that the user will be redirect back too
    $clientID = 'xxx';                              //The ID of the client
    $clientSecret = 'xxx';            //The sensitive and secret key of the client
    $scope = 'identify email';

    //Exchange the token
    $auth = discord_oauth_exchange($clientID, $clientSecret, $scope, $redirectURL, $code);

    echo '<strong>'.$redirectURL.'</strong><br />';

    if ($auth == null || !empty($auth['error'])) {
        printf('Failed: Authorization was bad: %s', $auth['error']);
        return -1;
    }

    $user = discord_oauth_get('/users/@me', $auth['access_token']);

    if ($user == null || !empty($user['message'])) {
        printf('Failed: /users/@me threw a error: %s', $user['message']);
        return -1;
    }

    return intval($user['id']);

}

// get current URL
$currentURL = $_SERVER['REQUEST_URI'];

// if currentURL contains 'discord'
if (strpos($currentURL, 'discord') !== false) {

    // If we don't have a code, redirect user
    if (!isset($_GET['code'])) {
        discord_oauth_redirect($clientID, $scope, $redirectURL);
        exit;
    }

}
//printf("<pre>\nCode: %s\nUser ID: %d", $_GET['code'], getUserId($_GET['code']));
?>