json - youtube视频信息json对象给出错误

Question

我正在使用YouTube API
我想使用youtube video info JSON对象获取youtube video信息
我正在使用下面给出的代码，但是当我尝试运行此代码时，它显示错误，因为“视频不需要密码即可解码”
请帮助我解决它，并告诉我代码中的问题在哪里

<?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

根据您的代码，$ cipher被设置为false，因为在file_get_contents($ info_url)的$ raw_data中找不到'use_cipher_signature'。