Simple Mirror for Telegram API requests

telegram-bot-mirror.php

<?php
const PASSPHRASE = 'your-secret-pass-phrase-for-encryption';

$encrypted_data = file_get_contents('php://input');
$data = decrypt($encrypted_data);

if (!isset($data['method'], $data['request'], $data['bot_token'])){
    die('no method or request');
}

$response = curl_post_json($data['bot_token'], $data['method'], $data['request']);
$encrypted_data = encrypt($response);
echo $encrypted_data;


// functions
function curl_post_json(string $bot_token, string $method, array $data): string
{
    $data_string = json_encode($data);

    $ch = curl_init("https://api.telegram.org/bot{$bot_token}/{$method}");
    curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
    curl_setopt($ch, CURLOPT_POSTFIELDS, $data_string);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_HTTPHEADER, array(
            'Content-Type: application/json',
            'Content-Length: ' . strlen($data_string))
    );
    $result = curl_exec($ch);
    curl_close($ch);
    return $result;
}

function encrypt(string $data): string
{
    $data_json_64 = base64_encode($data);
    $secret_key = hex2bin(PASSPHRASE);
    $iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length('aes-256-gcm'));
    $tag = '';
    $encrypted_64 = openssl_encrypt($data_json_64, 'aes-256-gcm', $secret_key, 0, $iv, $tag);
    $json = new stdClass();
    $json->iv = base64_encode($iv);
    $json->data = $encrypted_64;
    $json->tag = base64_encode($tag);
    return base64_encode(json_encode($json));
}

function decrypt(string $data): array
{
    $secret_key = hex2bin(PASSPHRASE);
    $json = json_decode(base64_decode($data), true);
    $iv = base64_decode($json['iv']);
    $tag = base64_decode($json['tag']);
    $encrypted_data = base64_decode($json['data']);
    $decrypted_data = openssl_decrypt($encrypted_data, 'aes-256-gcm', $secret_key, OPENSSL_RAW_DATA, $iv, $tag);
    return json_decode(base64_decode($decrypted_data),True);
}

Sample JSON input for telegram apis sendMessage method:

{
    "method": "sendMessage",
    "bot_token": "BOT_TOKEN",
    "request": {
        "chat_id": "CHAT_ID",
        "text": "MESSAGE",
        "parse_mode": "markdown",
        "disable_web_page_preview": true,
        "disable_notification": true
    }
}

Also see Encrypt / Decrypt JSON data between Python and PHP using AES 256 GCM