PHP 简单的WordPress缩略图功能

Posted 2021-05-15

function vp_get_thumb_url($text)
{
  global $post;
 
  $imageurl="";        
 
  // extract the thumbnail from attached imaged
  $allimages =&get_children('post_type=attachment&post_mime_type=image&post_parent=' . $post->ID );        
 
  foreach ($allimages as $img){                
     $img_src = wp_get_attachment_image_src($img->ID);
     break;                       
  }
 
  $imageurl=$img_src[0];
 
 
  // try to get any image
  if (!$imageurl)
  {
    preg_match('/<\s*img [^\>]*src\s*=\s*[\""\']?([^\""\'>]*)/i' ,  $text, $matches);
    $imageurl=$matches[1];
  }
 
  // try to get youtube video thumbnail
  if (!$imageurl)
  {
    preg_match("/([a-zA-Z0-9\-\_]+\.|)youtube\.com\/watch(\?v\=|\/v\/)([a-zA-Z0-9\-\_]{11})([^<\s]*)/", $text, $matches2);
 
    $youtubeurl = $matches2[0];
    if ($youtubeurl)
     $imageurl = "http://i.ytimg.com/vi/{$matches2[3]}/1.jpg"; 
   else preg_match("/([a-zA-Z0-9\-\_]+\.|)youtube\.com\/(v\/)([a-zA-Z0-9\-\_]{11})([^<\s]*)/", $text, $matches2);
 
   $youtubeurl = $matches2[0];
   if ($youtubeurl)
     $imageurl = "http://i.ytimg.com/vi/{$matches2[3]}/1.jpg"; 
  }
 
 
return $imageurl;
}

//Use
  global $post;
  $thumb=vp_get_thumb_url($post->post_content); 
  if ($thumb!='') echo '<img style=" width:150px;" src="'.$thumb.'" alt="'. get_the_title().'" />