Simple Youtube Statistics Script

<?php
 /* Youni's Simple Youtube Statistics Script
 * Shows quantity of subscribers, views and videos on any channel if channel does not hide info
 *
 * Usage: yoursite.com/pathtoscriptfolder/index.php?channel=channel_id
 * where channel_id is part of youtube link like this: UCEU9D6KIShdLeTRyH3IdSvw
 *
 * For using script you need to get your own YoutubeAPI Data v3 with access from browser
 * and fill the constant KEY
 * Also place your default channel id (link) into constant CHANNEL
 *
 * This script puts cached .txt files in its folder so be sure
 * to set up correct access rights, owner and group to folder where script is placed to.
 *
 * Published under license GPL v 3.0
 * Jan 12, 2021
*/

/* its foss: https://www.youtube.com/channel/UCEU9D6KIShdLeTRyH3IdSvw
From Youtube Documentation:
https://developers.google.com/youtube/v3/getting-started
YoutubeAPI Data v3 key:  ---place it here to store it----
* channel info: https://www.googleapis.com/youtube/v3/channels?part=snippet&id= ID &key= KEY
//Get videos from channel by YouTube Data API
$API_key    = 'Insert_Your_API_Key';
$channelID  = 'Insert_Channel_ID';
$maxResults = 10;
$videoList = json_decode(file_get_contents('https://www.googleapis.com/youtube/v3/search?order=date&part=snippet&channelId='.$channelID.'&maxResults='.$maxResults.'&key='.$API_key.''));
$url = 'https://www.googleapis.com/youtube/v3/search?order=date&part=snippet&channelId='.$chan.'&maxResults=50&key='.$key;
echo "url: $url <br>";
$video_list = json_decode(file_get_contents($url));
print_r($video_list);
get stat of video
https://www.googleapis.com/youtube/v3/videos?part=statistics&id=Q5mHPo2yDG8&key={YOUR_API_KEY}
its foss linux blog channel UCEU9D6KIShdLeTRyH3IdSvw
*/

ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

define('KEY', '...place YoutubeAPI Data V3 Key here to use script...');
define('CHANNEL', 'UCEU9D6KIShdLeTRyH3IdSvw'); //default: its foss linux blog channel UCEU9D6KIShdLeTRyH3IdSvw
$CHANNEL = CHANNEL;

$cache_info = 12000;
$cache_stat = 180;

function channel_info($channel = CHANNEL, $data = 'title') {
    global $cache_info;
    $cachefile = 'cache_info_' . $channel . '.txt';
    if ( file_exists($cachefile) && (time() - $cache_info < filemtime($cachefile)) ) {
        $cacheresult = unserialize(file_get_contents($cachefile));
        return $cacheresult[$data];
    } else {
        $json_string = file_get_contents('https://www.googleapis.com/youtube/v3/channels?part=snippet&id=' . $channel . '&key=' . KEY);
        $json = json_decode($json_string, true);
        if ( count($json,1) != 0 ) {
            $temp['title'] = $json['items']['0']['snippet']['title'];
            $temp['publishedAt'] = $json['items']['0']['snippet']['publishedAt'];
            $temp['icon'] = $json['items']['0']['snippet']['thumbnails']['default']['url'];

            $result[] = $temp;
            $youtubedata = serialize($temp);

            $fp = fopen($cachefile, 'w');
            fwrite($fp, $youtubedata);
            fclose($fp);
            return $temp[$data];
        } else {
            $result = unserialize(file_get_contents($cachefile));
            return $result[$type];
        }
    }
}


function channel_statistics($channel = CHANNEL, $type = 'views') {
    global $cache_stat;
    $cachefile = 'cache_stat_' . $channel . '.txt';
    if ( file_exists($cachefile) && (time() - filemtime($cachefile) < $cache_stat ) ) {
        $cacheresult = unserialize(file_get_contents($cachefile));
        return number_format($cacheresult[$type]);
    } else {
        if ( file_exists($cachefile)) {
            $t = time() - filemtime($cachefile);
        }
        $json_string = file_get_contents('https://www.googleapis.com/youtube/v3/channels?part=statistics&id=' . $channel . '&key=' . KEY);
        $json = json_decode($json_string, true);
        if ( count($json,1) != 0 ) {
            $temp['views'] = $json['items']['0']['statistics']['viewCount'];
            $temp['subscribers'] = $json['items']['0']['statistics']['subscriberCount'];
            $temp['count'] = $json['items']['0']['statistics']['videoCount'];

            $result[] = $temp;
            $youtubedata = serialize($temp);

            if ( file_exists($cachefile)) unlink($cachefile);
            $fp = fopen($cachefile, 'w');
            fwrite($fp, $youtubedata);
            fclose($fp);
            return number_format($temp[$type]);
        } else {
            $result = unserialize(file_get_contents($cachefile));
            return number_format($result[$type]);
        }
    }
}

if (isset($_GET['channel']) && (strlen($_GET['channel']) > 0) ) $CHANNEL = $_GET['channel'];
?>
<html><head><title>Channel statistics: <?php echo channel_info($CHANNEL, 'title'); ?></title>
<meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0">
</head>
<body>
<h2 style="text-align:center;">Channel statistics: <?php echo channel_info($CHANNEL, 'title'); ?></h2>
<p style="text-align:center;"><?php echo 'Subscribers: <b>' . channel_statistics($CHANNEL, 'subscribers') . '</b>'; ?></p>
<p style="text-align:center;"><?php echo 'Views: <b>' . channel_statistics($CHANNEL, 'views') . '</b>'; ?></p>
<p style="text-align:center;"><?php echo 'Videos total: <b>' . channel_statistics($CHANNEL, 'count') . '</b>'; ?></p>
<p>&nbsp;</p>
<p style="text-align:center;"><small>Age of a cache:
<?php $sec = time() - filemtime('cache_stat_' . $CHANNEL . '.txt');
if ($sec > 60) { $min = intval($sec/60); echo $min . ' minutes '; }
if ($sec % 60 > 0) { echo $sec % 60 . ' seconds' ; }
if ($sec < 1) { echo ' just created' ; }
?> </small></p>

<p style="text-align:center;">
<ul>
  <li><a href="https://studio.youtube.com">Go to your Youtube Studio</a></li>
  <li><a href="https://studio.youtube.com/channel/<?php echo $CHANNEL; ?>">Go to channel's Youtube Studio</a></li>
  <li><a href="https://studio.youtube.com/channel/<?php echo $CHANNEL; ?>/comments/inbox">Go to channel's Youtbue Comments</a></li>
</ul>
</p>

</body>
</html>