Setting up a Discord oauth2 login on my website (with PHP?) - authentication

Question

So I'm having troubles learning how to set up a login through discord on my site. I've been browsing for literally hours and haven't been able to find anything I understand...
At the moment, I have created the discord application, giving me a client ID and client secret, as well as a link back to my localhost:
https://discordapp.com/api/oauth2/authorize?client_id=550631359337594881&redirect_uri=http%3A%2F%2Flocalhost&response_type=code&scope=identify
At the moment I have it set up to redirect from a button to that URL, which then sends me to discord to accept. It then returns me to http://localhost?code=CODE_HERE
However, I don't know what I am supposed to do with this code. I am trying to set it up so that it will show the person's username with hashtag thing, and their profile picture.
I am currently using HTML, CSS, JS, and PHP on the site, but I think I might need to use something else, but I don't know how to set that up, or what it is I need. I am running my local server with XAMPP. I'd prefer if it is just PHP, but I'm open to other options.
Does anyone know how I can convert the code to a username + image?
Thanks in advance!

Answer 1

Try this
Credits to: eslachance
<?php
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
ini_set('max_execution_time', 300); //300 seconds = 5 minutes. In case if your CURL is slow and is loading too much (Can be IPv6 problem)
error_reporting(E_ALL);
define('OAUTH2_CLIENT_ID', '1234567890'); //Your client Id
define('OAUTH2_CLIENT_SECRET', 'verysecretclientcode'); //Your secret client code
$authorizeURL = 'https://discordapp.com/api/oauth2/authorize';
$tokenURL = 'https://discordapp.com/api/oauth2/token';
$apiURLBase = 'https://discordapp.com/api/users/#me';
session_start();
// Start the login process by sending the user to Discord's authorization page
if(get('action') == 'login') {
$params = array(
'client_id' => OAUTH2_CLIENT_ID,
'redirect_uri' => 'https://yoursite.location/ifyouneedit',
'response_type' => 'code',
'scope' => 'identify guilds'
);
// Redirect the user to Discord's authorization page
header('Location: https://discordapp.com/api/oauth2/authorize' . '?' . http_build_query($params));
die();
}
// When Discord redirects the user back here, there will be a "code" and "state" parameter in the query string
if(get('code')) {
// Exchange the auth code for a token
$token = apiRequest($tokenURL, array(
"grant_type" => "authorization_code",
'client_id' => OAUTH2_CLIENT_ID,
'client_secret' => OAUTH2_CLIENT_SECRET,
'redirect_uri' => 'https://yoursite.location/ifyouneedit',
'code' => get('code')
));
$logout_token = $token->access_token;
$_SESSION['access_token'] = $token->access_token;
header('Location: ' . $_SERVER['PHP_SELF']);
}
if(session('access_token')) {
$user = apiRequest($apiURLBase);
echo '<h3>Logged In</h3>';
echo '<h4>Welcome, ' . $user->username . '</h4>';
echo '<pre>';
print_r($user);
echo '</pre>';
} else {
echo '<h3>Not logged in</h3>';
echo '<p>Log In</p>';
}
if(get('action') == 'logout') {
// This must to logout you, but it didn't worked(
$params = array(
'access_token' => $logout_token
);
// Redirect the user to Discord's revoke page
header('Location: https://discordapp.com/api/oauth2/token/revoke' . '?' . http_build_query($params));
die();
}
function apiRequest($url, $post=FALSE, $headers=array()) {
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V4);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
$response = curl_exec($ch);
if($post)
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($post));
$headers[] = 'Accept: application/json';
if(session('access_token'))
$headers[] = 'Authorization: Bearer ' . session('access_token');
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
$response = curl_exec($ch);
return json_decode($response);
}
function get($key, $default=NULL) {
return array_key_exists($key, $_GET) ? $_GET[$key] : $default;
}
function session($key, $default=NULL) {
return array_key_exists($key, $_SESSION) ? $_SESSION[$key] : $default;
}
?>

Answer 2

You have the code which is used to authenticate with many endpoints of the discord API. You need the http://discordapp.com/api/users/#me Endpoint. You authenticate with the Authorization Header. Take a look at the Developer Portal to find out more about your endpoint