Dead simple youtube playlist randomizer

youtube-playlist-randomizer.php

<?php
/**
 * Dead simple youtube playlist randomizer
 * 
 * Detail here: https://dungnt.net/blog/php-youtube-playlist-randomizer
 */
date_default_timezone_set('Asia/Ho_Chi_Minh');

const API_ENDPOINT = 'https://www.googleapis.com/youtube/v3/playlistItems';
const PLAYLIST_ID = 'enter youtube playlist here';
const API_KEY = 'enter google api key here';

const DATA_FILE = 'youtube-playlist-randomizer.json';
const LOG_FILE = 'youtube-playlist-randomizer.log';

$video_ids = []; // format: video_id => video_title

const ERROR_MSG = "Some thing went wrong. Please try again!";

function write_log($msg)
{
    $now = date("Y-m-d H:i:s");
    file_put_contents(
        LOG_FILE,
        "[$now] $msg" . PHP_EOL,
        FILE_APPEND
    );
}

function send_request($url)
{
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);

    $response = curl_exec($ch);
    $curl_errno = curl_errno($ch);
    $curl_error = curl_error($ch);

    curl_close($ch);

    if ($curl_errno > 0) {
        write_log("cURL Error ($curl_errno): $curl_error");
        exit(ERROR_MSG);
    }

    try {
        $data = json_decode($response, true);
    }
    catch (Exception $e) {
        write_log($e);
        exit(ERROR_MSG);
    }

    if (isset($data['error']) && !empty($data['error']))
    {
        write_log("Response error: " . $data['error']['code'] . PHP_EOL . $response);
        exit(ERROR_MSG);
    }

    return $data;
}

function get_playlist_videos($page_token = '')
{
    global $video_ids;

	$query_url = API_ENDPOINT . '?part=snippet&maxResults=50&playlistId=' . PLAYLIST_ID . '&key=' . API_KEY;
	if ($page_token != '') {
		$query_url .= "&pageToken={$page_token}";
	}

	$data = send_request($query_url);

    foreach($data['items'] as $item) {
        $video_id = $item['snippet']['resourceId']['videoId'];
        $video_title = $item['snippet']['title'];

        $video_ids[$video_id] = $video_title;
    }

    if (isset($data['nextPageToken']) && $data['nextPageToken'] != '') {
        return get_playlist_videos($data['nextPageToken']);
    }
}

function random_video()
{
    global $video_ids;

    $video_list = array_keys($video_ids);
    $video_count = count($video_list);
    $random_number = rand(0, $video_count - 1);

    return $video_list[$random_number];
}

if (!file_exists(DATA_FILE)) {
    get_playlist_videos();
    file_put_contents(DATA_FILE, json_encode($video_ids));
} else {
    $cache_content = file_get_contents(DATA_FILE);
    $video_ids = json_decode($cache_content, true);
}

$redirect_video_id = random_video();

header("Location: https://www.youtube.com/watch?v={$redirect_video_id}&list=" . PLAYLIST_ID);
die();