Automanted code deployment based on github webhooks (on pull request merge into the main branch)

github_webhook.php

<?php
const REPO_DIR = "/env";
const DISCORD_WEBHOOK = "...";
const TOKEN = "...";

if (key_exists('auth', $_GET) && $_GET['auth'] == TOKEN) {
    $payload = json_decode($_POST['payload'], true);

    if (key_exists("action", $payload) &&
        $payload["action"] == "closed" &&
        $payload["pull_request"]["merged_at"] != null &&
        $payload["pull_request"]["base"]["ref"] == "main") {

        header("HTTP/1.1 202 Accepted");

        $out = "";
        $res = 0;

        chdir(REPO_DIR);
        exec("git pull", $out, $res);

        if ($res == 0) {
            notifyDiscord([
                "content" => "Code deployed! Consult the pull request above for more info!"
            ]);
        }
    } else {
        header("HTTP/1.1 204 No Content");
    }
    die();
}
header("HTTP/1.1 403 Forbidden");
?>
    <h1>403 Forbidden</h1>
<?php

function notifyDiscord($body)
{
    $curl = curl_init(DISCORD_WEBHOOK);
    curl_setopt($curl, CURLOPT_URL, DISCORD_WEBHOOK);
    curl_setopt($curl, CURLOPT_POST, true);
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($curl, CURLOPT_HTTPHEADER, [
        "Content-Type: application/json"
    ]);

    curl_setopt($curl, CURLOPT_POSTFIELDS, json_encode($body));
    curl_exec($curl);
    curl_close($curl);
}