Subversion Repositories yt_downloader

#!/usr/bin/php

<?php

// ViaThinkSoft YouTube Downloader Util 2.2

// Revision: 2022-02-05

// Author: Daniel Marschall <www.daniel-marschall.de>

// Licensed under the terms of the Apache 2.0 License

//

// For syntax and other documentation, please read the file README.

// ------------------------------------------------------------------------------------------------

error_reporting(E_ALL | E_NOTICE | E_STRICT | E_DEPRECATED);

define('AUTO_API_KEY', '~/.yt_api_key');

define('AUTO_COOKIE_FILE', '~/.yt_cookies');

define('DOWNLOAD_SIMULATION_MODE', false);

define('DEFAULT_SEARCH_ORDER', 'relevance');

define('DEFAULT_SEARCH_MAXRESULTS', 10);

putenv("LANG=de_DE.UTF-8"); // required if video titles contain non-ASCII symbols

require_once __DIR__ . '/youtube_functions.inc.phps';

// Check if we are running in command line

if (PHP_SAPI !== 'cli') {

	fwrite(STDERR, "Error: Can only run in CLI mode\n");

	exit(2);

}

// Global vars

$listFilenameStack = array();

// Default values

$allow_creation_outputdir = false;

$type = 'v:';

$outputDir = '';

$alreadyDownloaded = '';

$failList = '';

$failTreshold = 3;

$rest_args = array();

$verbose = false;

$mp3id_transfer = true;

$apikey = '';

$resultcache = '';

$extra_args =

//            '-k ' . // The additional "-k" option in the above makes youtube-dl keep downloaded videos.

              '-i ' . // continue upon download errors

              '-c ';  // resume partially downloaded video files

$default_template = '%(title)s-%(id)s.%(ext)s';

$cookie_file = AUTO_COOKIE_FILE;

// Parse arguments

// We do not use getopt() at the moment, because the important functionality "optind" is only available in PHP 7.1, which is not yet distributed with most of the stable Linux distros

$init_extra_args = false;

$argv_bak = $_SERVER['argv'];

array_shift($argv_bak);

while (count($argv_bak) > 0) {

	$arg = array_shift($argv_bak);

	$arg2 = $arg . ' ' . (isset($argv_bak[0]) ? $argv_bak[0] : '');

	$m = null;

	if (preg_match('@^(/t|\-t|\-\-type)(\s+|=)(.*)$@s', $arg2, $m)) {

		array_shift($argv_bak);

		if (count($rest_args) > 0) syntax_error("Invalid argument: ".$rest_args[0]);

		$type = $m[3];

	} else if (preg_match('@^(/o|\-o|\-\-outputDir)(\s+|=)(.*)$@s', $arg2, $m)) {

		array_shift($argv_bak);

		if (count($rest_args) > 0) syntax_error("Invalid argument: ".$rest_args[0]);

		$outputDir = $m[3];

	} else if (preg_match('@^(/a|\-a|\-\-alreadyDownloaded)(\s+|=)(.*)$@s', $arg2, $m)) {

		array_shift($argv_bak);

		if (count($rest_args) > 0) syntax_error("Invalid argument: ".$rest_args[0]);

		$alreadyDownloaded = $m[3];

	} else if (preg_match('@^(/f|\-f|\-\-failList)(\s+|=)(.*)$@s', $arg2, $m)) {

		array_shift($argv_bak);

		if (count($rest_args) > 0) syntax_error("Invalid argument: ".$rest_args[0]);

		$failList = $m[3];

	} else if (preg_match('@^(/F|\-F|\-\-failTreshold)(\s+|=)(.*)$@s', $arg2, $m)) {

		array_shift($argv_bak);

		if (count($rest_args) > 0) syntax_error("Invalid argument: ".$rest_args[0]);

		$failTreshold = $m[3];

	} else if (preg_match('@^(/C|\-C|\-\-resultcache)(\s+|=)(.*)$@s', $arg2, $m)) {

		array_shift($argv_bak);

		if (count($rest_args) > 0) syntax_error("Invalid argument: ".$rest_args[0]);

		$resultcache = $m[3];

	} else if (preg_match('@^(/T|\-T|\-\-default-template)(\s+|=)(.*)$@s', $arg2, $m)) {

		array_shift($argv_bak);

		if (count($rest_args) > 0) syntax_error("Invalid argument: ".$rest_args[0]);

		$default_template = $m[3];

	} else if (preg_match('@^(/A|\-A|\-\-api-key)(\s+|=)(.*)$@s', $arg2, $m)) {

		array_shift($argv_bak);

		if (count($rest_args) > 0) syntax_error("Invalid argument: ".$rest_args[0]);

		$apikey = file_exists($m[3]) ? trim(file_get_contents($m[3])) : $m[3];

	} else if (preg_match('@^(\-\-cookies)(\s+|=)(.*)$@s', $arg2, $m)) {

		array_shift($argv_bak);

		if (count($rest_args) > 0) syntax_error("Invalid argument: ".$rest_args[0]);

		$cookie_file = file_exists($m[3]) ? trim(file_get_contents($m[3])) : $m[3];

	} else if (preg_match('@^(/X|\-X|\-\-extra-args)(\s+|=)(.*)$@s', $arg2, $m)) {

		array_shift($argv_bak);

		if (count($rest_args) > 0) syntax_error("Invalid argument: ".$rest_args[0]);

		if ($init_extra_args) {

			$extra_args .= ' ' . $m[3]; // user has multiple "-X" arguments. append.

		} else {

			$extra_args = $m[3]; // overwrite defaults

			$init_extra_args = true;

		}

	} else if (preg_match('@^(/\?|/h|\-\?|\-h|\-\-help)$@s', $arg, $m)) {

		if (count($rest_args) > 0) syntax_error("Invalid argument: ".$rest_args[0]);

		help();

	} else if (preg_match('@^(/V|\-V|\-\-version)$@s', $arg, $m)) {

		if (count($rest_args) > 0) syntax_error("Invalid argument: ".$rest_args[0]);

		version();

	} else if (preg_match('@^(/v|\-v|\-\-verbose)$@s', $arg, $m)) {

		if (count($rest_args) > 0) syntax_error("Invalid argument: ".$rest_args[0]);

		$verbose = true;

	} else if (preg_match('@^(/N|\-N|\-\-no-mp3-tagtransfer)$@s', $arg, $m)) {

		if (count($rest_args) > 0) syntax_error("Invalid argument: ".$rest_args[0]);

		$mp3id_transfer = false;

	} else if (preg_match('@^(/O|\-O|\-\-create-outputdir)$@s', $arg, $m)) {

		if (count($rest_args) > 0) syntax_error("Invalid argument: ".$rest_args[0]);

		$allow_creation_outputdir = true;

	} else if ($arg == '--') {

		if (count($rest_args) > 0) syntax_error("Invalid argument: ".$rest_args[0]);

		$rest_args = $argv_bak;

		break;

	} else {

		$rest_args[] = $arg;

	}

}

unset($arg);

unset($argv_bak);

unset($init_extra_args);

// Validity checks

if ((substr($type,0,2) != 'a:') && (substr($type,0,2) != 'v:')) syntax_error("Type must be either 'v:' or 'a:'. '$type' is not valid.");

if (count($rest_args) == 0) syntax_error("Please enter at least one desired video for downloading");

if ($failTreshold <= 0) syntax_error("Fail treshold has invalid value. Must be >0.");

$cookie_file = expand_tilde($cookie_file);

if (!file_exists($cookie_file)) $cookie_file = '';

// Try to download/update youtube-dl into local directory

$newest_version_md5 = get_latest_ytdl_md5sum();

if (!$newest_version_md5) {

	fwrite(STDERR, "Failed to get MD5 sum of latest version of 'youtube-dl' from GitHub. Will not try to download/update 'youtube-dl' into local directory.\n");

} else {

	if (!file_exists(__DIR__.'/youtube-dl') || ($newest_version_md5 != md5_file(__DIR__.'/youtube-dl'))) {

		// Try to download/update the file in our directory. It should be the newest available, since YT often breaks downloader

		if (file_exists(__DIR__.'/youtube-dl')) {

			echo "Trying to update 'youtube-dl' in local directory...\n";

		} else {

			echo "Trying to download 'youtube-dl' into local directory...\n";

		}

		if (!@file_put_contents(__DIR__.'/youtube-dl', file_get_contents('https://yt-dl.org/downloads/latest/youtube-dl'))) {

			fwrite(STDERR, "Failed to download 'youtube-dl' into local directory (file_get_contents).\n");

		} else {

			if (!@chmod(__DIR__.'/youtube-dl', 0544)) {

				fwrite(STDERR, "Failed to download 'youtube-dl' into local directory (chmod 544).\n");

				@unlink(__DIR__.'/youtube-dl'); // try to delete, otherwise we might try to execute a non-executable file

			}

		}

	}

}

if (command_exists(__DIR__.'/youtube-dl')) {

	echo "Will use 'youtube-dl' from local directory\n";

	define('YTDL_EXE', __DIR__.'/youtube-dl');

} else {

	// Download failed. Is at least a package installed?

	if (command_exists('youtube-dl')) {

		echo "Will use 'youtube-dl' from Linux package\n";

		define('YTDL_EXE', 'youtube-dl');

	} else {

		fwrite(STDERR, "This script requires the tool/package 'youtube-dl'. Please install it first.\n");

		exit(1);

	}

}

// Now process the videos

yt_set_apikey_callback('_getApikey');

foreach ($rest_args as $resource) {

	if ($verbose) echo "Handle: $resource\n";

	if (strpos($resource, ':') === false) {

		fwrite(STDERR, "Invalid resource '$resource' (you are missing the prefix, e.g. vurl: or vid:). Skipping.\n");

	} else {

		list($resourceType, $resourceValue) = explode(':', $resource, 2);

		ytdwn_handle_resource($resourceType, $resourceValue);

	}

}

// ------------------------------------------------------------------------------------------------

function ytdwn_handle_resource($resourceType, $resourceValue) {

	if ($resourceType == 'vid') {

		$video_id = parse_quoting($resourceValue);

		ytdwn_video_id($video_id);

	} else if ($resourceType == 'vurl') {

		$video_url = parse_quoting($resourceValue);

		$video_id  = getVideoIDFromURL($video_url);

		if (!$video_id) {

			fwrite(STDERR, "$video_url is not a valid YouTube video URL. Skipping.\n");

		} else {

			ytdwn_video_id($video_id);

		}

	} else if ($resourceType == 'pid') {

		$playlist_id = parse_quoting($resourceValue);

		ytdwn_playlist_id($playlist_id);

	} else if ($resourceType == 'purl') {

		$playlist_url = parse_quoting($resourceValue);

		$playlist_id  = getPlaylistIDFromURL($playlist_url);

		if (!$playlist_id) {

			fwrite(STDERR, "$playlist_url is not a valid YouTube playlist URL. Skipping\n");

		} else {

			ytdwn_playlist_id($playlist_id);

		}

	} else if ($resourceType == 'cid') {

		$channel_id = parse_quoting($resourceValue);

		$m = null;

		if (preg_match('@\[search=(.+)\]@ismU', $channel_id, $m)) {

			$search = $m[1];

			$channel_id = preg_replace('@\[search=(.+)\]@ismU', '', $channel_id);

		} else {

			$search = ''; // default

		}

		$search = parse_quoting($search);

		ytdwn_channel_id($channel_id, $search);

	} else if ($resourceType == 'cname') {

		$channel_name = parse_quoting($resourceValue);

		$m = null;

		if (preg_match('@\[search=(.+)\]@ismU', $channel_name, $m)) {

			$search = $m[1];

			$channel_name = preg_replace('@\[search=(.+)\]@ismU', '', $channel_name);

		} else {

			$search = ''; // default

		}

		$search = parse_quoting($search);

		$channel_name = parse_quoting($channel_name);

		$channel_id = yt_get_channel_id($channel_name);

		if (!$channel_id) {

			fwrite(STDERR, "URL $channel_name is a valid YouTube channel or username. Skipping.\n");

		} else {

			ytdwn_channel_id($channel_id, $search);

		}

	} else if ($resourceType == 'curl') {

		$channel_url = parse_quoting($resourceValue);

		$m = null;

		if (preg_match('@\[search=(.+)\]@ismU', $channel_url, $m)) {

			$search = $m[1];

			$channel_url = preg_replace('@\[search=(.+)\]@ismU', '', $channel_url);

		} else {

			$search = ''; // default

		}

		$search = parse_quoting($search);

		$channel_url = parse_quoting($channel_url);

		$channel_id = curl_to_cid($channel_url);

		if (!$channel_id) {

			fwrite(STDERR, "URL $channel_url is a valid YouTube channel or username URL. Skipping\n");

		} else {

			ytdwn_channel_id($channel_id, $search);

		}

	} else if ($resourceType == 'search') {

		$searchterm = parse_quoting($resourceValue);

		$order = '';

		$m = null;

		if (preg_match('@\[order=(.+)\]@ismU', $searchterm, $m)) {

			$order = $m[1];

			$searchterm = preg_replace('@\[order=(.+)\]@ismU', '', $searchterm);

		} else {

			$order = DEFAULT_SEARCH_ORDER; // default

		}

		$order = parse_quoting($order);

		$maxresults = '';

		if (preg_match('@\[maxresults=(.+)\]@ismU', $searchterm, $m)) {

			$maxresults = $m[1];

			$searchterm = preg_replace('@\[maxresults=(.+)\]@ismU', '', $searchterm);

		} else {

			$maxresults = DEFAULT_SEARCH_MAXRESULTS; // default

		}

		$maxresults = parse_quoting($maxresults);

		$searchterm = parse_quoting($searchterm);

		ytdwn_search($searchterm, $order, $maxresults);

	} else if ($resourceType == 'list') {

		$list_files = glob(parse_quoting($resourceValue)); // in case the user entered a wildcard, e.g. *.list

		foreach ($list_files as $list_file) {

			if (!file_exists($list_file)) {

				fwrite(STDERR, "List file $list_file does not exist. Skipping\n");

			} else {

				ytdwn_list_file($list_file);

			}

		}

	} else {

		fwrite(STDERR, "Resource type '$resourceType' is not valid. Skipping $resourceType:$resourceValue.\n");

	}

}

function ytdwn_list_file($list_file) {

	global $listFilenameStack, $verbose;

	if ($verbose) echo "Processing list file '$list_file' ...\n";

	$listFilenameStack[] = $list_file;

	$lines = file($list_file);

	foreach ($lines as $line) {

		$line = trim($line);

		if ($line == '') continue;

		if ($line[0] == '#') continue;

		if (strpos($line, ':') === false) {

			fwrite(STDERR, "Invalid resource '$line' (you are missing the prefix, e.g. vurl: or vid:). Skipping.\n");

		} else {

			list($resourceType, $resourceValue) = explode(':',$line,2);

			ytdwn_handle_resource($resourceType, $resourceValue);

		}

	}

	array_pop($listFilenameStack);

}

function ytdwn_channel_id($channel_id, $search='') {

	global $type;

	global $verbose;

	if ($verbose) echo "Processing channel ID '$channel_id' ...\n";

	// List the videos of the channel

	$cont = !empty(_getResultcache()) && file_exists(_getResultcache()) ? file_get_contents(_getResultcache()) : '';

	$out = json_decode($cont, true);

	if ($out == NULL) $out = array();

	if (!empty(_getResultcache())) {

		$stats = yt_get_channel_stats($channel_id);

		if ($stats === false) {

			fwrite(STDERR, "Cannot get stats for channel with ID '$channel_id'\n");

			return;

		}

		$videocount = $stats['videoCount'];

		$key = (!empty($search)) ? 'cid:'.$channel_id.'/'.$search : 'cid:'.$channel_id;

		if (!isset($out[$key])) $out[$key] = array();

		$videocount_old = isset($out[$key]['count']) ? $out[$key]['count'] : -1;

	} else {

		$videocount = -1;

		$videocount_old = -2;

		$key = '';

	}

	if ($videocount_old != $videocount) { // Attention: This might not work if videos are deleted and added (= the count stays the same)

		if ($verbose && !empty(_getResultcache())) echo "Video count changed from $videocount_old to $videocount\n";

		$out[$key]['count'] = $videocount;

		if (!empty($search)) {

			$out[$key]['results'] = yt_channel_items($channel_id, $search);

		} else {

			$out[$key]['results'] = yt_channel_items($channel_id);

		}

	} else {

		if ($verbose) echo "Video count for channel is still $videocount, keep ".count($out[$key]['results'])." results.\n";

	}

	// Save the cache

	try {

		if (!empty(_getResultcache())) file_put_contents(_getResultcache(), json_encode($out));

	} catch(Exception $e) {

		fwrite(STDERR, "Cannot write result cache\n");

	}

	// Now download

	if (!$out[$key]['results']) {

		fwrite(STDERR, "Cannot get result for channel with ID '$channel_id'\n");

		return;

	}

	foreach ($out[$key]['results'] as list($id, $title)) {

		if ($verbose) echo "Downloading '$title' as ".hf_type($type)." ...\n";

		ytdwn_video_id($id);

	}

}

function ytdwn_playlist_id($playlist_id) {

	global $type;

	global $verbose;

	if ($verbose) echo "Processing playlist ID '$playlist_id' ...\n";

	// List the videos of the playlist

	$cont = !empty(_getResultcache()) && file_exists(_getResultcache()) ? file_get_contents(_getResultcache()) : '';

	$out = json_decode($cont, true);

	if ($out == NULL) $out = array();

	if (!empty(_getResultcache())) {

		$stats = yt_get_playlist_stats($playlist_id);

		if ($stats === false) {

			fwrite(STDERR, "Cannot get stats for playlist with ID '$playlist_id'\n");

			return;

		}

		$videocount = $stats['itemCount'];

		$key = 'pid:'.$playlist_id;

		if (!isset($out[$key])) $out[$key] = array();

		$videocount_old = isset($out[$key]['count']) ? $out[$key]['count'] : -1;

	} else {

		$videocount = -1;

		$videocount_old = -2;

		$key = '';

	}

	if ($videocount_old != $videocount) { // Attention: This might not work if videos are deleted and added (= the count stays the same)

		if ($verbose && !empty(_getResultcache())) echo "Video count changed from $videocount_old to $videocount\n";

		$out[$key]['count'] = $videocount;

		$out[$key]['results'] = yt_playlist_items($playlist_id);

	} else {

		if ($verbose) echo "Video count for playlist is still $videocount, keep ".count($out[$key]['results'])." results.\n";

	}

	// Save the cache

	try {

		if (!empty(_getResultcache())) file_put_contents(_getResultcache(), json_encode($out));

	} catch(Exception $e) {

		fwrite(STDERR, "Cannot write result cache\n");

	}

	// Now download

	if (!$out[$key]['results']) {

		fwrite(STDERR, "Cannot get result for playlist with ID '$playlist_id'\n");

		return;

	}

	foreach ($out[$key]['results'] as list($id, $title)) {

		if ($verbose) echo "Downloading '$title' as ".hf_type($type)." ...\n";

		ytdwn_video_id($id);

	}

}

function ytdwn_search($search, $order='', $maxresults=-1) {

	global $type;

	global $verbose;

	if ($verbose) echo "Searching for '$search' ...\n";

	// Perform the search and list the videos

	$results = yt_search_items($search, $order, $maxresults);

	// Now download

	if (!$results) {

		fwrite(STDERR, "Cannot get data for search '$search'\n");

		return;

	}

	foreach ($results as list($id, $title)) {

		if ($verbose) echo "Downloading '$title' as ".hf_type($type)." ...\n";

		ytdwn_video_id($id);

	}

}

function ytdwn_video_id($video_id) {

	global $type;

	global $verbose;

	global $mp3id_transfer;

	global $extra_args;

	global $default_template;

	global $failTreshold;

	global $cookie_file;

	if (DOWNLOAD_SIMULATION_MODE) {

		echo "SIMULATE download of video id $video_id as ".hf_type($type)." to "._getOutputDir()."\n";

		return;

	}

	if (!empty(_getAlreadyDownloaded()) && in_alreadydownloaded_file($type, $video_id)) {

		if ($verbose) echo "Video $video_id has already been downloaded. Skip.\n";

		return true;

	}

	if (!empty(_getFailList()) && (ytdwn_fail_counter($type, $video_id) >= $failTreshold)) {

		if ($verbose) echo "Video $video_id has failed too often. Skip.\n";

		return true;

	}

	$out = '';

	$code = -1;

	$outputTemplate = rtrim(_getOutputDir(), '/').'/'.$default_template;

	if (substr($type,0,2) == 'v:') {

		$format = substr($type,2);

		if (!empty($format)) {

			exec(YTDL_EXE.' -o '.escapeshellarg($outputTemplate).' '.$extra_args.(empty($cookie_file) ? '' : ' --cookies '.$cookie_file).' '.escapeshellarg(vid_to_vurl($video_id)).' --format '.escapeshellarg($format), $out, $code);

		} else {

			exec(YTDL_EXE.' -o '.escapeshellarg($outputTemplate).' '.$extra_args.(empty($cookie_file) ? '' : ' --cookies '.$cookie_file).' '.escapeshellarg(vid_to_vurl($video_id)), $out, $code);

		}

	} else if (substr($type,0,2) == 'a:') {

		$format = substr($type,2);

		if (!empty($format)) {

			exec(YTDL_EXE.' -o '.escapeshellarg($outputTemplate).' '.$extra_args.(empty($cookie_file) ? '' : ' --cookies '.$cookie_file).' '.escapeshellarg(vid_to_vurl($video_id)).' --extract-audio --audio-format '.escapeshellarg($format), $out, $code);

		} else {

			exec(YTDL_EXE.' -o '.escapeshellarg($outputTemplate).' '.$extra_args.(empty($cookie_file) ? '' : ' --cookies '.$cookie_file).' '.escapeshellarg(vid_to_vurl($video_id)).' --extract-audio', $out, $code);

		}

		if (($mp3id_transfer) && ($format == 'mp3')) mp3_transfer_vid_to_id();

	} else assert(false);

	if ($code == 0) {

		if ($verbose) fwrite(STDOUT, "Successfully downloaded video ID $video_id as ".hf_type($type)."\n");

		if (!empty(_getAlreadyDownloaded())) {

			try {

				addto_alreadydownloaded_file($type, $video_id);

			} catch(Exception $e) {

				fwrite(STDERR, "Cannot add to already downloaded file\n");

			}

		}

	} else {

		fwrite(STDERR, "Error downloading $video_id! (Code $code)\n");

		if (!empty(_getFailList())) {

			try {

				ytdwn_register_fail($type, $video_id, $code);

			} catch(Exception $e) {

				fwrite(STDERR, "Cannot register fail\n");

			}

		}

		return false;

	}

	return true;

}

function vid_to_vurl($video_id) {

	return "https://www.youtube.com/watch?v=$video_id";

}

function EndsWith($Haystack, $Needle){

	return strrpos($Haystack, $Needle) === strlen($Haystack)-strlen($Needle);

}

function mp3_transfer_vid_to_id() {

	global $verbose;

	global $default_template;

	if (!command_exists('id3v2')) {

		if ($verbose) echo "Note: Tool id3v2 is not installed. Will not transfer the YouTube ID into the MP3 ID Tag\n";

		return false;

	}

	if (!EndsWith($default_template, '-%(id)s.%(ext)s'))  {

		if ($verbose) echo "Note: Cannot transfer video tag to MP3 because default template does not end with '-%(id)s.%(ext)s'.\n";

		return false;

	}

	$allok = true;

	$files = glob(rtrim(_getOutputDir(), '/').'/*-???????????.mp3');

	foreach ($files as $filename) {

		$m = null;

		if (!preg_match('@-([a-zA-Z0-9\-_]{11})\.mp3$@ismU', $filename, $m)) continue;

		$yt_id = $m[1];

		if (!yt_check_video_id($yt_id)) continue; // just to be sure

		$orig_ts = filemtime($filename);

		$ec = -1;

		system('id3v2 -c '.escapeshellarg($yt_id).' '.escapeshellarg($filename), $ec);

		touch($filename, $orig_ts);

		if ($ec != 0) {

			fwrite(STDERR, "Cannot set ID tag for file $filename\n");

			$allok = false;

			continue;

		}

		$target_filename = str_replace("-$yt_id.mp3", '.mp3', $filename);

		if (!intelligent_rename($filename, $target_filename)) {

			fwrite(STDERR, "Cannot move file $filename to $target_filename\n");

			$allok = false;

			continue;

		}

	}

	return $allok;

}

function curl_to_cid($channel_url) {

	$m = null;

	if (preg_match("@https{0,1}://(www\\.|)youtube\\.com/user/(.*)(/|&|\\?)@ismU", $channel_url.'&', $m)) {

		$username = $m[2];

		$channel_id = yt_get_channel_id($username);

		return $channel_id;

	} else if (preg_match("@https{0,1}://(www\\.|)youtube\\.com/(channel|c)/(.*)(/|&|\\?)@ismU", $channel_url.'&', $m)) {

		$channel_id = $m[3];

		return $channel_id;

	} else {

		return false;

	}

}

function in_alreadydownloaded_file($type, $video_id) {

	$lines = file(_getAlreadyDownloaded());

	foreach ($lines as $line) {

		if (trim($line) == rtrim($type,':').':'.$video_id) {

			return true;

		}

	}

	return false;

}

function addto_alreadydownloaded_file($type, $video_id) {

	file_put_contents(_getAlreadyDownloaded(), rtrim($type,':').':'.$video_id."\n", FILE_APPEND);

}

function syntax_error($msg) {

	fwrite(STDERR, "Syntax error: ".trim($msg)."\n");

	fwrite(STDERR, "Please use argument '--help' to show the syntax rules.\n");

	exit(2);

}

function _help() {

	global $argv;

	$out = '';

	$own = file_get_contents($argv[0]);

	$help = explode('// ----', $own, 2)[0];

	$m = null;

	$help = preg_match_all('@^//(.*)$@mU', $help, $m);

	foreach ($m[1] as $line) {

		$out .= substr($line,1)."\n";

	}

	return $out;

}

function help() {

	echo _help();

	exit(0);

}

function version() {

	echo explode("\n\n", _help(), 2)[0]."\n";

	exit(0);

}

function command_exists($command) {

	// https://stackoverflow.com/questions/592620/check-if-a-program-exists-from-a-bash-script

	$ec = -1;

	system('command -v '.escapeshellarg($command).' > /dev/null', $ec);

	return ($ec == 0);

}

function hf_type($type) {

	if (strpos($type, ':') === false) return $type; // invalid type (missing ':')

	list($av, $format) = explode(':', $type);

	if ($av == 'a') $av = 'audio';

	else if ($av == 'v') $av = 'video';

	else return $type; // invalid type

	return (!empty($format)) ? $format.'-'.$av : $av;

}

function expand_tilde($path) {

	// Source: http://jonathonhill.net/2013-09-03/tilde-expansion-in-php/

	if (function_exists('posix_getuid') && strpos($path, '~') !== false) {

		$info = posix_getpwuid(posix_getuid());

		$path = str_replace('~', $info['dir'], $path);

	}

	return $path;

}

function _getLastListname() {

	global $listFilenameStack;

	$listname = ''; // default

	if (count($listFilenameStack) > 0) {

		$listname = $listFilenameStack[count($listFilenameStack)-1];

		$listname = pathinfo($listname, PATHINFO_FILENAME); // remove file extension, e.g. ".list"

	}

	return $listname;

}

function _getApiKey() {

	global $apikey;

	$out = $apikey;

	if (empty($out)) {

		$auto_api_key = AUTO_API_KEY;

		$auto_api_key = expand_tilde($auto_api_key);

		$auto_api_key = str_replace('[listname]', _getLastListname(), $auto_api_key);

		if (file_exists($auto_api_key)) {

			$out = trim(file_get_contents($auto_api_key));

		} else {

			syntax_error("Please specify a YouTube API key with argument '-A'.");

		}

	} else {

		$out = str_replace('[listname]', _getLastListname(), $out);

		$out = expand_tilde($out);

		if (file_exists($out)) {

			$out = trim(file_get_contents($out));

		} else {

			// Assume, $out is a key, not a file

		}

	}

	if (!yt_check_apikey_syntax($out)) syntax_error("'$out' is not a valid API key, not an existing file containing an API key.\n");

	return $out;

}

function _getResultCache() {

	global $resultcache;

	if (empty($resultcache)) return '';

	$out = expand_tilde($resultcache);

	$out = str_replace('[listname]', _getLastListname(), $out);

	if (!file_exists($out)) {

		@touch($out);

		if (!file_exists($out)) {

			fwrite(STDERR, "File '$out' cannot be created. Disable feature.\n");

			return '';

		}

	}

	return $out;

}

function _getAlreadyDownloaded() {

	global $alreadyDownloaded;

	if (empty($alreadyDownloaded)) return '';

	$out = expand_tilde($alreadyDownloaded);

	$out = str_replace('[listname]', _getLastListname(), $out);

	if (!file_exists($out)) {

		@touch($out);

		if (!file_exists($out)) {

			fwrite(STDERR, "File '$out' cannot be created. Disable feature.\n");

			return '';

		}

	}

	return $out;

}

function _getFailList() {

	global $failList;

	if (empty($failList)) return '';

	$out = expand_tilde($failList);

	$out = str_replace('[listname]', _getLastListname(), $out);

	if (!file_exists($out)) {

		@touch($out);

		if (!file_exists($out)) {

			fwrite(STDERR, "File '$out' cannot be created. Disable feature.\n");

			return '';

		}

	}

	return $out;

}

function _getOutputDir() {

	global $outputDir, $allow_creation_outputdir;

	if (empty($outputDir)) return '.';

	$out = expand_tilde($outputDir);

	$out = str_replace('[listname]', _getLastListname(), $out);

	if ($allow_creation_outputdir) {

		if (!is_dir($out)) {

			mkdir($out, 0777, true);

			if (!is_dir($out)) {

				fwrite(STDERR, "Output directory '$out' does not exist.\n");

				exit(1);

			}

		}

	} else {

		if (!is_dir($out)) {

			fwrite(STDERR, "Output directory '$out' does not exist.\n");

			exit(1);

		}

	}

	return $out;

}

function parse_quoting($str) {

	if ((substr($str,0,1) == '"') && (substr($str,-1,1) == '"')) {

		$str = substr($str,1,strlen($str)-2);

		$escape = false;

		$out = '';

		for ($i=0; $i<strlen($str); $i++) {

			$char = $str[$i];

			if ($char == '\\') {

				if ($escape) {

					$out .= $char;

					$escape = false;

				} else {

					$escape = true;

				}

			} else {

				$out .= $char;

			}

		}

		$str = $out;

	}

	return $str;

}

function ytdwn_register_fail($type, $video_id, $code) {

	// Note: Error code $code ist currently not used

	$file = _getFailList();

	$cont = file_get_contents($file);

	$m = null;

	if (preg_match("@Video ID ".preg_quote($video_id,'@')." failed (\d+) time\(s\) with type ".preg_quote($type,'@')."@ismU", $cont, $m)) {

		$cont = preg_replace("@Video ID ".preg_quote($video_id,'@')." failed (\d+) time\(s\) with type ".preg_quote($type,'@')."@ismU",

		                     "Video ID $video_id failed ".($m[1]+1)." time(s) with type $type", $cont);

		file_put_contents($file, $cont);

	} else {

		file_put_contents($file, "Video ID $video_id failed 1 time(s) with type $type\n", FILE_APPEND);

	}

}

function ytdwn_fail_counter($type, $video_id) {

	$file = _getFailList();

	$cont = file_get_contents($file);

	$m = null;

	if (preg_match("@Video ID ".preg_quote($video_id,'@')." failed (\d+) time\(s\) with type ".preg_quote($type,'@')."@ismU", $cont, $m)) {

		return $m[1];

	} else {

		return 0;

	}

}

function intelligent_rename($src, $dest) {

	$pos = strrpos($dest, '.');

	$ext = substr($dest, $pos);

	$namewoext = substr($dest, 0, $pos);

	$failcnt = 1;

	$dest_neu = $dest;

	while (file_exists($dest_neu)) {

		$failcnt++;

		$dest_neu = "$namewoext ($failcnt)$ext";

	}

	return rename($src, $dest_neu);

}

function get_latest_ytdl_md5sum() {

	$ch = curl_init();

	curl_setopt($ch, CURLOPT_URL, 'https://yt-dl.org/downloads/latest/MD5SUMS');

	#curl_setopt($ch, CURLOPT_HEADER, false);

	curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);

	curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

	$cont = curl_exec($ch);

	$m = null;

	if (preg_match('@^(.+)  youtube\-dl$@ismU', $cont, $m)) {

		return $m[1];

	} else {

		return false;

	}

}