Telegram Webhook n Database Example

<?php
$conn = mysqli_connect("localhost", "root", "password_here", "dbname");

$content = file_get_contents("php://input");
$update = json_decode($content, true);
$bot_token = "1809829596:AAF5zQdYM4lSddaXzpH8pfU_0OBpXh2tjdE";

$chat_id = $update["message"]["chat"]["id"];
$message = $update["message"]["text"];
$command1 = explode(" ", $message, 2);
$command = $command1[0];

if($command == "/add_user"){
    $user_name = $command1[1];
    mysqli_query($conn, "INSERT INTO tablename (username) VALUES ($user_name)");
    send_message($chat_id, "A user '$user_name' added to database");
}

if($command == "/get_user"){
    $output_name = "";
    $query = mysqli_query($conn, "SELECT * FROM tablename");
    while($fetch = mysqli_fetch_assoc($query)){
        $output_name .= $fetch["username"]."\n";
    }
    send_message($chat_id, $output_name);

}

function send_message($id, $text)
{
    global $bot_token;
    $text = urlencode($text);
    file_get_contents("https://api.telegram.org/bot$bot_token/sendMessage?chat_id=$id&text=$text");
}