youtube video info json object gives error - json

Question

I am working on youtube api
and I want to get youtube video information using youtube video info JSON object
and I am using a code as given below but when I try to run this code it is showing error as "Video Is not cipher not needed to decode"
please help me to solve it out also tell me where is the problem in code
<?php
// Video with cipher signature
$video_id = "zDrNLZ1uJ2w";
// get_video_info url formation
// although for cipher signature we have to get the details from the video's webapge not from get_video_info object
$info_url = "http://www.youtube.com/get_video_info?el=detailpage&asv=3&video_id=".$video_id;
// youtube webpage url formation
$yt_url = 'http://www.youtube.com/watch?v='.$video_id.'&gl=US&persist_gl=1&hl=en&persist_hl=1';;
// get the contents from the url
$raw_data = file_get_contents($info_url);
// parse the data received and save it as an array
$output = array();
parse_str($raw_data,$output);
// check the status of the get_video_info object
if($output['status']=='ok'){
// check for the cipher signature
$cipher = (isset($output['use_cipher_signature']) && $output['use_cipher_signature']=='True') ? true : false;
// If cipher is true then we have to decode it
if($cipher == true){
// if cipher is true then we have to change the plan and get the details from the video's youtube wbe page
$yt_html = file_get_contents($yt_url);
// parse for the script containing the configuration
preg_match('/ytplayer.config = {(.*?)};/',$yt_html,$match);
$yt_object = #json_decode('{'.$match[1].'}') ;
/// check if we are able to parse data
if(!is_object($yt_object)){
echo 'Sorry! Unable to parse Data';
}else{
// parse available formats
$formats = $yt_object->args->url_encoded_fmt_stream_map;
// get the player id from assets section
$player_id = strbtwn($yt_object->assets->js,'html5player-','.js');
$player_id = explode("/", $player_id);
$player_id = $player_id[0];
echo 'Player ID: '.$player_id.'<br /><hr />';
// get the algo dictionary
// first check if the file exists
if(file_exists('./algo.json'))
$algos = json_decode(file_get_contents('algo.json'),true);
else{
// API call to fetch the algo dictionary
$algos_dict = file_get_contents("http://api.gitnol.com/getAlgo.php?playerID=".$player_id);
// saving the algo dictonary in local env for easy access
// Note: Developers should save the dictionary in their local env.
// Only make the API call for the new player ids which is not present in the algo dictionary.
// Repeated violation will results in IP ban.
file_put_contents('algo.json', $algos_dict);
$algos = json_decode($algos_dict,true);
}
/// check if the algo exist for the given player id
if(!array_key_exists($player_id, $algos)){
// if the algo dictionary is old then fetch a new one
$algos_dict = file_get_contents("http://api.gitnol.com/getAlgo.php?playerID=".$player_id);
file_put_contents('algo.json', $algos_dict);
$algos = json_decode($algos_dict,true);
$algo = $algos[$player_id][1];
}else{
$algo = $algos[$player_id][1];
}
echo 'Algo Used: '.$algo.'<br /><hr />';
// download links formation
$dlinks = array();
$links = explode(',',$formats);
echo 'Download links <br /><br />';
foreach ($links as $link) {
parse_str($link,$linkarr);
// parse link array one by one and decrypt the signature
$dlinks[$linkarr['itag']] = $linkarr['url'] . "&signature=" . decrypt($linkarr['s'],$algo);
echo $linkarr['itag'].'<br />';
echo $dlinks[$linkarr['itag']].'<br /><br />';
}
echo '<hr />';
}
}else{
echo 'Video Is not cipher not needed to decode';
}
}else{
echo 'Unable to get Video Info';
}
// string helper function
function strbtwn($content,$start,$end){
$r = explode($start, $content);
if (isset($r[1])){
$r = explode($end, $r[1]);
return $r[0];
}
return '';
}
// signature decoding
// parse the python string operation into php string operation
function decrypt($sig, $algo){
$funcarr = explode(' + ', $algo);
$decrypt = '';
foreach($funcarr as $singfunc){
$singfunc = substr($singfunc,2,-1);
$operators = explode(':', $singfunc);
if (sizeof($operators) == 1) {
$decrypt .= $sig[$operators[0]];
}
if (sizeof($operators) == 2) {
if($operators[0] == ''){
$decrypt .= substr($sig, 0 ,$operators[1]);
}
if($operators[1] == ''){
$decrypt .= substr($sig, $operators[0]);
}
if($operators[0] >= 0 && $operators[1] >= 0){
$decrypt .= substr($sig, $operators[0], $operators[1] - $operators[0]);
}
}
if (sizeof($operators) == 3) {
if($operators[0] == '' && $operators[1] == ''){
$decrypt .= strrev($sig);
}
if($operators[0] >=0 && $operators[1] == '' && $operators[0] != ''){
$decrypt .= strrev(substr($sig, 0, $operators[0] + 1));
}
if($operators[0] >=0 && $operators[1] >= 0 && $operators[0] != '' && $operators[1] != ''){
$decrypt .= strrev(substr($sig, $operators[1] + 1, $operators[0] - $operators[1]));
}
}
}
return $decrypt;
}
?>

Answer 1

According to your code $cipher is being set to false because 'use_cipher_signature' is not found in the $raw_data from file_get_contents($info_url).