您需要涵盖几个步骤。

从MetaBox embed获取ID根据ID提取可用大小的列表，如果图像不存在，请将图像导入到库中，并附加新文件以发布

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STEP 2 | YouTube

从YouTube生成一个大小数组以供以后使用：

function getYoutTubeImagesFromID($yt_id, $prefix = \'https:\') {

    $yt_url = \'img.youtube.com\'; //  can be \'i3.ytimg.com\'

    $sizes = array(0, 1, 2, 3, "default", "hqdefault", "mqdefault", "sddefault", "maxresdefault");
    $result = array();
    foreach($sizes as $size) {
        $result [ $size ] = "{$prefix}//img.youtube.com/vi/{$yt_id}/{$size}.jpg";
    }

    return array(
        \'id\'    => $yt_id,
        \'link\'  => "{$prefix}//youtu.be/{$yt_id}",
        \'sizes\' => $result,
    );
}

要测试这一点，请循环查看ID列表。

$yt_videos = array(\'cV5yxrZpuXg\', \'LtBTHqi8Gmw\', \'VEAY-nRlP5c\', \'IWeasYydL8Y\', \'fCVXpcR9KDY\');

foreach($yt_videos as $yt_id) {

    $ytImages = getYoutTubeImagesFromID($yt_id);

    $src = $ytImages[ \'sizes\' ][ \'hqdefault\' ];
    $link = $ytImages[ \'link\' ];

    echo "<a href=\\"{$link}\\" target=\\"_blank\\" ><img src=\\"{$src}\\" ></a>";

    print_r($ytImages);
}

它们应各自生成可用于导入的大小信息。

Array
(
    [id] => cV5yxrZpuXg
    [link] => https://youtu.be/cV5yxrZpuXg
    [sizes] => Array
        (
            [0] => https://img.youtube.com/vi/cV5yxrZpuXg/0.jpg
            [1] => https://img.youtube.com/vi/cV5yxrZpuXg/1.jpg
            [2] => https://img.youtube.com/vi/cV5yxrZpuXg/2.jpg
            [3] => https://img.youtube.com/vi/cV5yxrZpuXg/3.jpg
            [default] => https://img.youtube.com/vi/cV5yxrZpuXg/default.jpg
            [hqdefault] => https://img.youtube.com/vi/cV5yxrZpuXg/hqdefault.jpg
            [mqdefault] => https://img.youtube.com/vi/cV5yxrZpuXg/mqdefault.jpg
            [sddefault] => https://img.youtube.com/vi/cV5yxrZpuXg/sddefault.jpg
            [maxresdefault] => https://img.youtube.com/vi/cV5yxrZpuXg/maxresdefault.jpg
        )

)

<小时>

STEP 2 | Vimeo

收集Vimeo视频信息

function getVimeoImagesFromID($vimeo_id, $prefix = \'https:\') {

    $vimeo_url = "{$prefix}//vimeo.com/api/v2/video/{$vimeo_id}.php";

    if( ! $vimeo_hash = @file_get_contents($vimeo_url)) {
        return false;
    }

    $result = unserialize($vimeo_hash);

    return ( count($result) === 1 ) ? array_shift($result) : $result;
}

// your vimeo id 
$vimeo_id = 71472926;

// get available information for video
if($vimeo_hash = getVimeoImagesFromID($vimeo_id)) {

    // grab the largest image possible
    $vimeo_src = $vimeo_hash [ \'thumbnail_large\' ];

    echo $vimeo_src; // https://i.vimeocdn.com/video/445043557_640.jpg
}

<小时>

STEP 3 | Sideload Image

media_sideload_image 从YT到服务器的图像。一定要抓住thumbnail_id 从产生的src.

// your youtube id
$yt_id = \'cSXlOeKusWs\';

// size information for id
$ytImages = getYoutTubeImagesFromID($yt_id);

// max res image
$url = $ytImages[ \'sizes\' ][ \'maxresdefault\' ];

// sideload image
$src = media_sideload_image(esc_url($url), NULL, \'\', \'src\');

// convert src to id
$thumbnail_id = attachment_url_to_postid($src);

<小时>一

Array
(
    [id] => cV5yxrZpuXg
    [link] => https://youtu.be/cV5yxrZpuXg
    [sizes] => Array
        (
            [0] => https://img.youtube.com/vi/cV5yxrZpuXg/0.jpg
            [1] => https://img.youtube.com/vi/cV5yxrZpuXg/1.jpg
            [2] => https://img.youtube.com/vi/cV5yxrZpuXg/2.jpg
            [3] => https://img.youtube.com/vi/cV5yxrZpuXg/3.jpg
            [default] => https://img.youtube.com/vi/cV5yxrZpuXg/default.jpg
            [hqdefault] => https://img.youtube.com/vi/cV5yxrZpuXg/hqdefault.jpg
            [mqdefault] => https://img.youtube.com/vi/cV5yxrZpuXg/mqdefault.jpg
            [sddefault] => https://img.youtube.com/vi/cV5yxrZpuXg/sddefault.jpg
            [maxresdefault] => https://img.youtube.com/vi/cV5yxrZpuXg/maxresdefault.jpg
        )

)
thumbnail_id.
set_post_thumbnail( $post, $thumbnail_id );