Get Telegram files direct link

bot.php

<?php
// Configuration

$token = '123:abc';
$adminId = 123456;
$webhookSecret = 'random-long-text';

// Security

if ($_SERVER['REQUEST_METHOD'] !== 'POST')
    die('method');

else if ($_GET['secret'] !== $webhookSecret)
    die('secret');

// Update

$update = json_decode(file_get_contents('php://input'))->message;
$chatId = $update->chat->id;
$messageId = $update->message_id;
$type = detectUpdateType($update);

// Main Process

if ((string)$chatId !== (string)$adminId)
    die();

$fileDetails = getFileDetails($type, $update);

$getFile = bot('getFile', ['file_id' => $fileDetails->file_id], true);

if (!$getFile->ok)
    die('error');

$filePath = $getFile->result->file_path;
$fileExtension = explode('.', $filePath)[1];
$fileLink = 'https://api.telegram.org/file/bot' . $token . '/' . $filePath;
$localFilePath = 'files/' . $fileDetails->file_unique_id . '.' . $fileExtension;

bot('sendMessage', [
    'chat_id' => $chatId,
    'text' => print_r([
        $type,
        $update->$type,
        $getFile,
        $fileDetails,
        $localFilePath,
        $fileExtension,
        $fileLink,
        $localFilePath
    ])
]);

bot('sendMessage', [
    'chat_id' => $chatId,
    'text' => $fileLink
]);

// Functions

/**
 * Send a request to the Telegram API
 *
 * @param string $method
 * @param null|array $data
 * @param bool $return
 *
 * @return bool|object
 */
function bot(string $method, array $data = null, bool $return = false) {
    global $token;

    $url = 'https://api.telegram.org/bot' . $token . '/' . $method;

    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    if (!empty($data))
        curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($data));

    $result = curl_exec($ch);

    if (curl_error($ch))
        return false;
    else
        return $return ? json_decode($result) : null;
}

function readableFileSize(int $size) {
    static $units = ['B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];
    $step = 1024;
    $i = 0;
    while (($size / $step) > 0.9) {
        $size = $size / $step;
        $i++;
    }
    return round($size, 2) . $units[$i];
}

/**
 * Detect type of update (photo, audio etc.)
 *
 * @param array $update
 *
 * @return bool|string
 */
function detectUpdateType(object $update) {
    $types = ['photo', 'video', 'voice', 'document', 'audio', 'video_note', 'animation'];

    foreach ($types as $type) {
        if (isset($update->$type))
            return $type;
    }

    return false;
}

function getFileDetails(string $type, object $update) {
    $result = $update->$type;

    if ($type === 'photo')
        $result = end($result);

    return $result ?? null;
}