Source of file YouTube.php

<?php

namespace AudioDidact\SupportedSites;

use AudioDidact\Video;

use AudioDidact\GlobalFunctions;

/**

 * Class YouTube

 */

class YouTube extends SupportedSite {

	// Setup global variables

	/** @var string YouTube URL */

	private $YouTubeBaseURL = "http://www.youtube.com/";

	/**

	 * YouTube constructor. Gets the video information, checks for it in the user's feed.

	 *

	 * @param string $str

	 * @param boolean $isVideo

	 * @throws \Exception

	 */

	public function __construct($str, $isVideo){

		$this->video = new Video();

		// If there is a URL/ID, continue

		if($str != null){

			$this->video->setURL($str);

			$this->video->setIsVideo($isVideo);

			// Set video ID from setYoutubeID and time to current time

			$this->video->setId($this->setYoutubeID($str));

			$this->video->setFilename($this->video->getId());

			$this->video->setThumbnailFilename($this->video->getFilename() . ".jpg");

			$this->video->setTime(time());

			$key = GOOGLE_API_KEY;

			// Get video author, title, and description from YouTube API

			$info = json_decode(GlobalFunctions::file_get_contents_no_verify("https://www.googleapis.com/youtube/v3/videos?part=snippet&id="

				. $this->video->getId() .

				"&fields=items/snippet/description,items/snippet/title,items/snippet/channelTitle&key=" .

				$key), true);

			// If the lookup fails, send this error to the UI as a JSON array

			if(!isset($info['items'][0]['snippet'])){

				throw new \Exception("ID Inaccessible");

			}

			$info = $info['items'][0]['snippet'];

			$this->video->setTitle($info["title"]);

			$this->video->setAuthor($info["channelTitle"]);

			$this->video->setDesc($info["description"]);

		}

	}

	/**

	 * Set YouTube ID from a given string using parseYoutubeURL

	 *

	 * @param string $str

	 * @return bool

	 * @throws \Exception

	 */

	private function setYoutubeID($str){

		// Try and parse the string into a usable ID

		$tmpId = $this->parseYoutubeURL($str);

		$vidId = ($tmpId !== false) ? $tmpId : $str;

		if(mb_strpos($vidId, "/playlist") > -1){

			throw new \Exception("URL is a playlist. AudioDidact does not currently support playlists.");

		}

		if(mb_strpos($vidId, "/c/") > -1 || strpos($vidId, "/channel/") > -1 || strpos($vidId, "/user/") > -1){

			throw new \Exception("URL is a channel. AudioDidact does not, and likely will not ever, support downloading of channels.");

		}

		$url = sprintf($this->YouTubeBaseURL . "watch?v=%s", $vidId);

		// Get HTTP status of the video url and make sure that it is

		// 200 = OK

		// 301 = Moved Permanently

		// 302 = Moved Temporarily

		if($this->cURLHTTPStatus($url) !== 200 && $this->cURLHTTPStatus($url) !== 301 && $this->cURLHTTPStatus($url)

			!== 302

		){

			throw new \Exception("Invalid Youtube video ID: $vidId");

		}

		return $vidId;

	}

	/**

	 * Download thumbnail using videoID from YouTube's image server

	 */

	public function downloadThumbnail(){

		$path = getcwd() . DIRECTORY_SEPARATOR . DOWNLOAD_PATH . DIRECTORY_SEPARATOR;

		$thumbnail = $path . $this->video->getThumbnailFilename();

		file_put_contents($thumbnail, fopen("https://i.ytimg.com/vi/" . $this->video->getID() . "/mqdefault.jpg", "r"));

		// Set the thumbnail file as publicly accessible

		@chmod($thumbnail, 0775);

	}

	/**

	 * Download video using download URL from Python script and then call downloadWithPercentage to actually download

	 * the video

	 *

	 * @throws \Exception

	 */

	public function downloadVideo(){

		$path = getcwd() . DIRECTORY_SEPARATOR . DOWNLOAD_PATH . DIRECTORY_SEPARATOR;

		$videoFilename = $this->video->getFilename() . ".mp4";

		$videoPath = $path . $videoFilename;

		$url = $this->getDownloadURL($this->video->getID());

		if(mb_strpos($url, "Error:") > -1){

			error_log("$url");

			throw new \Exception($url);

		}

		/* Actually download the video from the url and print the

		 * percentage to the screen with JSON

		 */

		$this->downloadWithPercentage($url, $videoPath);

		// Set the video file as publicly accessible

		@chmod($videoPath, 0775);

		$this->video->setDuration(SupportedSite::getDurationSeconds($videoPath));

	}

	/**

	 * Gets lowest quality mp4 download url based on a given id.

	 *

	 * @param $id

	 * @return string

	 * @throws \Exception

	 */

	private function getDownloadURL($id){

		$url = $this->YouTubeBaseURL . "watch?v=" . $id;

		$html = file_get_contents($url);

		$restrictionPattern = "og:restrictions:age";

		if(mb_strpos($html, $restrictionPattern) > -1){

			return "Error: Age restricted video. Unable to download.";

		}

		$jsonStartPattern = "ytplayer.config = ";

		$patternIndex = mb_strpos($html, $jsonStartPattern);

		// In case video is unable to play

		if($patternIndex == -1){

			return "Error: Unable to find start pattern.";

		}

		$start = $patternIndex + mb_strlen($jsonStartPattern);

		$html = mb_substr($html, $start);

		$unmatchedBracketsCount = 0;

		$index = 1;

		$htmlArr = GlobalFunctions::mb_str_split($html);

		$i = 0;

		foreach($htmlArr as $i => $ch){

			if($ch == "{"){

				$unmatchedBracketsCount += 1;

			}

			else if($ch == "}"){

				$unmatchedBracketsCount -= 1;

				if($unmatchedBracketsCount == 0){

					break;

				}

			}

		}

		$offset = $index + $i;

		$youtubeJSONData = json_decode(mb_substr($html, 0, $offset), true);

		if($youtubeJSONData == null){

			throw new \Exception("<h3>Download Failed</h3><h4>Unable to find JSON data from YouTube</h4>");

		}

		if(isset($youtubeJSONData["args"]["livestream"]) && $youtubeJSONData["args"]["livestream"] && (!isset($youtubeJSONData["args"]["url_encoded_fmt_stream_map"]) || $youtubeJSONData["args"]["url_encoded_fmt_stream_map"] == "")){

			throw new \Exception("<h3>Download Failed</h3><h4>This URL is a livestream, try again when the stream has ended</h4>");

		}

		if(!isset($youtubeJSONData["args"]["url_encoded_fmt_stream_map"]) || $youtubeJSONData["args"]["url_encoded_fmt_stream_map"] == ""){

			error_log("Couldn't download " . $id . " because could not find url_encoded_fmt_stream_map");

			error_log(json_encode($youtubeJSONData));

			throw new \Exception("<h3>Download Failed</h3><h4>Try again later</h4>");

		}

		$encodedStreamMap = $youtubeJSONData["args"]["url_encoded_fmt_stream_map"];

		$dct = [];

		$videos = explode(",", $encodedStreamMap);

		foreach($videos as $i => $video){

			$video = explode("&", $video);

			foreach($video as $v){

				$key = explode("=", $v)[0];

				$value = explode("=", $v)[1];

				$dct[$key][] = urldecode($value);

			}

		}

		$youtubeJSONData["args"]["stream_map"] = $dct;

		$streamMap = $dct;

		unset($dct, $videos, $html, $htmlArr, $youtubeJSONData);

		$videoURLs = $streamMap["url"];

		$downloads = [];

		foreach($videoURLs as $i => $vurl){

			$qualityProfile = $this->getQualityProfilesFromURL($vurl);

			$downloads[] = ["url" => $vurl, "ext" => $qualityProfile["extension"], "res" => $qualityProfile["resolution"]];

		}

		$downloadURL = "";

		$resolution = 999999;

		// Find lowest quality mp4

		foreach($downloads as $v){

			if($v["ext"] == "mp4" && intval(mb_substr($v["res"], 0, -1)) < $resolution){

				$resolution = intval(mb_substr($v["res"], 0, -1));

				$downloadURL = $v["url"];

			}

		}

		return $downloadURL;

	}

	/**

	 * Returns a quality profile or false based on a url.

	 *

	 * @param $url

	 * @return bool|mixed

	 */

	private function getQualityProfilesFromURL($url){

		$qp = [];

		$qp[5] = ["flv", "240p", "Sorenson H.263", "N/A", "0.25", "MP3", "64"];

		$qp[17] = ["3gp", "144p", "MPEG-4 Visual", "Simple", "0.05", "AAC", "24"];

		$qp[36] = ["3gp", "240p", "MPEG-4 Visual", "Simple", "0.17", "AAC", "38"];

		$qp[43] = ["webm", "360p", "VP8", "N/A", "0.5", "Vorbis", "128"];

		$qp[100] = ["webm", "360p", "VP8", "3D", "N/A", "Vorbis", "128"];

		$qp[18] = ["mp4", "360p", "H.264", "Baseline", "0.5", "AAC", "96"];

		$qp[22] = ["mp4", "720p", "H.264", "High", "2-2.9", "AAC", "192"];

		$qp[82] = ["mp4", "360p", "H.264", "3D", "0.5", "AAC", "96"];

		$qp[83] = ["mp4", "240p", "H.264", "3D", "0.5", "AAC", "96"];

		$qp[84] = ["mp4", "720p", "H.264", "3D", "2-2.9", "AAC", "152"];

		$qp[85] = ["mp4", "1080p", "H.264", "3D", "2-2.9", "AAC", "152"];

		foreach($qp as $k => $q){

			$keys = ["extension", "resolution", "video_codec", "profile", "video_bitrate", "audio_codec", "audio_bitrate"];

			foreach($keys as $k2 => $v){

				$qp[$k][$v] = $q[$k2];

			}

			foreach(array_keys($qp[$k]) as $key){

				if(!in_array($key, $keys, true)){

					unset($qp[$k][$key]);

				}

			}

		}

		$itagPattern = '/itag=(\d+)/';

		preg_match_all($itagPattern, $url, $itag);

		if(isset($itag[1][0]) && intval($itag[1][0]) > -1){

			$itag = intval($itag[1][0]);

			return $qp[$itag];

		}

		return false;

	}

	/**

	 * Use cURL to get the HTTP status of a given URL

	 *

	 * @param $url

	 * @return int

	 */

	private function cURLHTTPStatus($url){

		$ch = curl_init($url);

		curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:11.0) Gecko Firefox/11.0");

		curl_setopt($ch, CURLOPT_REFERER, $this->YouTubeBaseURL);

		curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

		curl_setopt($ch, CURLOPT_NOBODY, 1);

		curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 5);

		curl_exec($ch);

		$int = curl_getinfo($ch, CURLINFO_HTTP_CODE);

		curl_close($ch);

		return intval($int);

	}

	/**

	 * Parse a YouTube URL to get the video ID

	 *

	 * @param $url

	 * @return bool

	 */

	private function parseYoutubeURL($url){

		$pattern = '#^(?:https?://)?';

		$pattern .= '(?:www\.)?';

		$pattern .= '(?:';

		$pattern .= 'youtu\.be/';

		$pattern .= '|youtube\.com';

		$pattern .= '(?:';

		$pattern .= '/embed/';

		$pattern .= '|/v/';

		$pattern .= '|/watch\?v=';

		$pattern .= '|/watch\?.+&v=';

		$pattern .= ')';

		$pattern .= ')';

		$pattern .= '([\w-]{11})';

		$pattern .= '(?:.+)?$#x';

		preg_match($pattern, $url, $matches);

		return (isset($matches[1])) ? $matches[1] : false;

	}

	public static function supportsURL($url){

		return (mb_strpos($url, "youtube") > -1) || (mb_strpos($url, "youtu.be") > -1);

	}

}