EDIT3：我得到了一些外部帮助，并完全改变了我的代码，现在使用xpath来选择div，而不是使用html源代码中的第n个img。我很高兴地说，这是工作！现在我的问题是添加一个ELSEIF来评估不同的类别，而不仅仅是一个类别。我似乎被这种逻辑束缚住了。我曾尝试在“if（in\\u array（\'mongong.GoGo.mn\'，$cat\\u name））”循环中添加ELSEIF，但这只会引发意外的ELSEIF错误。我又迷路了。。。代码如下：
add_action(\'publish_post\', \'custom_auto_featured_image_publish_post\',10,2);
function custom_auto_featured_image_publish_post($post_id, $post) {
// get category of post ID
$cat_detail=get_the_category($post_id);
$cat_name = array();
foreach($cat_detail as $cd){
$cat_name[] = $cd->cat_name;
}
// get all image tags
//if ( get_post_meta($post_id, \'_apt_skip_post_thumb\', true) ) {
if ( in_array( \'Mongolia.GoGo.mn\', $cat_name ) ) {
// get custom post field
$custom_fields = get_post_custom($post_id);
$htmlURL = $custom_fields[\'original_guid\'][0];
// try to load the webpage
$dom = new domDocument;
@$dom->loadHTML(file_get_contents($htmlURL));
$finder = new DomXPath($dom);
$classname="newscover";
$content = $finder->query("//*[contains(concat(\' \', normalize-space(@class), \' \'), \' $classname \')]");
$imageURL = \'\';
if($content->length){
if($content->item(0)->childNodes->length > 1){
$imageURL = $content->item(0)->childNodes->item(1)->getAttribute(\'src\');
}
}else{
$content = $dom->getElementById(\'ncbubuhome\');
@$dom->loadHTML($content->nodeValue);
$images = $dom->getElementsByTagName(\'img\');
foreach ($content->childNodes as $node) {
if($node->nodeName != \'#text\'){
foreach ($node->childNodes as $childNode) {
if($childNode->nodeName == \'img\'){
$imageURL = $childNode->getAttribute(\'src\');
break;
}
}
}
}
}
if($imageURL != \'\'){
$imageURL = str_replace(\' \', \'%20\', $imageURL);
// download image from url
$tmp = download_url($imageURL);
$ext = pathinfo(basename($imageURL), PATHINFO_EXTENSION);
$finfo = finfo_open(FILEINFO_MIME_TYPE);
$name = strtotime("now") . \'_feature_image.\' . $ext;
$type = finfo_file($finfo, $tmp);
$file = array(
\'name\' => $name,
\'size\' => filesize($tmp),
\'type\' => $type,
\'tmp_name\' => $tmp,
\'error\' => UPLOAD_ERR_OK
);
$overrides = array(
\'test_form\' => false,
\'test_size\' => true,
\'test_upload\' => true,
);
// upload image to server
$file_uploaded = wp_handle_sideload( $file, $overrides );
// $filename should be the path to a file in the upload directory.
$filename = $file_uploaded[\'file\'];
$filetype = $file_uploaded[\'type\'];
// Prepare an array of post data for the attachment.
$attachment = array(
\'guid\' => $file_uploaded[\'url\'],
\'post_mime_type\' => $filetype,
\'post_title\' => preg_replace( \'/\\.[^.]+$/\', \'\', basename( $filename ) ),
\'post_content\' => \'\',
\'post_status\' => \'inherit\'
);
// Insert the attachment.
$attach_id = wp_insert_attachment( $attachment, $filename );
// Generate the metadata for the attachment, and update the database record.
$attach_data = wp_generate_attachment_metadata( $attach_id, $filename );
wp_update_attachment_metadata( $attach_id, $attach_data );
// set the featured image
update_post_meta($post_id, \'_thumbnail_id\', $attach_id);
}
}
//}
}
原文：我试图通过函数以编程方式设置特色缩略图。php。这是我写了一半的代码（其余的代码来自另一篇StackExchange帖子，非常有用。似乎没有任何语法错误（我已经打开了调试），但当使用正确的类别创建新帖子时，什么都没有发生。我对PHP非常陌生，所以我认为这是我的代码的一个问题，但我不确定具体在哪里。
（这个逻辑已经过时了。现在我使用xpath来选择我想要的类）我通过DOM在自定义字段中加载URL的HTML，然后提取IMG标记。之后，If-ElseIf查看类别并根据类别抓取第n幅图像，并将其附加为帖子缩略图。我觉得逻辑是对的，但我可能遗漏了什么。
//以前过时的代码段
EDIT2：我还在研究这个。我已经从Wordpress论坛获得了一些帮助来更改我的代码，但这个功能似乎仍然不起作用。这里的逻辑似乎很简单，但不起作用。我就是不明白。。。这是我当前的代码。
//以前过时的代码段2
最合适的回答,由SO网友:Robert Ritz 整理而成
好的，我知道了！以下是我使用的代码：
add_action(\'publish_post\', \'custom_auto_featured_image_publish_post\',10,2);
function custom_auto_featured_image_publish_post($post_id, $post) {
// get category of post ID
$cat_detail=get_the_category($post_id);
$cat_name = array();
foreach($cat_detail as $cd){
$cat_name[] = $cd->cat_name;
}
$custom_fields = get_post_custom($post_id);
if(isset($custom_fields[\'original_guid\']) && !empty($custom_fields[\'original_guid\'])){
$htmlURL = $custom_fields[\'original_guid\'][0];
// try to load the webpage
$dom = new domDocument;
$imageURL = \'\';
@$dom->loadHTML(file_get_contents($htmlURL));
if ( in_array( \'Mongolia.GoGo.mn\', $cat_name ) ) {
$finder = new DomXPath($dom);
$classname="newscover";
$content = $finder->query("//*[contains(concat(\' \', normalize-space(@class), \' \'), \' $classname \')]");
if($content->length){
if($content->item(0)->childNodes->length > 1){
$imageURL = $content->item(0)->childNodes->item(1)->getAttribute(\'src\');
}
}else{
$content = $dom->getElementById(\'ncbubuhome\');
if($content->childNodes->length){
foreach ($content->childNodes as $node) {
if($node->nodeName != \'#text\'){
foreach ($node->childNodes as $childNode) {
if($childNode->nodeName == \'img\'){
$imageURL = $childNode->getAttribute(\'src\');
break;
}
}
}
}
}
}
}elseif ( in_array( \'InfoMongolia\', $cat_name ) ) {
$finder = new DomXPath($dom);
$classname="full_text";
$content = $finder->query("//*[contains(concat(\' \', normalize-space(@class), \' \'), \' $classname \')]");
if($content->length){
if($content->item(0)->childNodes->length){
foreach ($content->item(0)->childNodes as $node) {
if($node->nodeName == \'img\'){
$imageURL = $node->getAttribute(\'src\');
break;
}
}
}
}
if($imageURL != \'\'){
if (filter_var($imageURL, FILTER_VALIDATE_URL) === false) {
$domain = \'http://www.infomongolia.com/\';
$imageURL = str_replace(\'../\', \'\', $imageURL);
$imageURL = $domain . $imageURL;
}
}
} elseif ( in_array( \'UBPost\', $cat_name ) ) {
$finder = new DomXPath($dom);
$classname="full_text";
$content = $finder->query("//*[contains(concat(\' \', normalize-space(@class), \' \'), \' $classname \')]");
if($content->length){
if($content->item(0)->childNodes->length){
foreach ($content->item(0)->childNodes as $node) {
if($node->nodeName == \'img\'){
$imageURL = $node->getAttribute(\'src\');
break;
}
}
}
}
if($imageURL != \'\'){
if (filter_var($imageURL, FILTER_VALIDATE_URL) === false) {
$domain = \'http://www.infomongolia.com/\';
$imageURL = str_replace(\'../\', \'\', $imageURL);
$imageURL = $domain . $imageURL;
}
}
}
if($imageURL != \'\'){
$imageURL = str_replace(\' \', \'%20\', $imageURL);
// download image from url
$tmp = download_url($imageURL);
$ext = pathinfo(basename($imageURL), PATHINFO_EXTENSION);
$finfo = finfo_open(FILEINFO_MIME_TYPE);
$name = strtotime("now") . \'_feature_image.\' . $ext;
$type = finfo_file($finfo, $tmp);
$file = array(
\'name\' => $name,
\'size\' => filesize($tmp),
\'type\' => $type,
\'tmp_name\' => $tmp,
\'error\' => UPLOAD_ERR_OK
);
$overrides = array(
\'test_form\' => false,
\'test_size\' => true,
\'test_upload\' => true,
);
// upload image to server
$file_uploaded = wp_handle_sideload( $file, $overrides );
// $filename should be the path to a file in the upload directory.
$filename = $file_uploaded[\'file\'];
$filetype = $file_uploaded[\'type\'];
// Prepare an array of post data for the attachment.
$attachment = array(
\'guid\' => $file_uploaded[\'url\'],
\'post_mime_type\' => $filetype,
\'post_title\' => preg_replace( \'/\\.[^.]+$/\', \'\', basename( $filename ) ),
\'post_content\' => \'\',
\'post_status\' => \'inherit\'
);
// Insert the attachment.
$attach_id = wp_insert_attachment( $attachment, $filename );
// Generate the metadata for the attachment, and update the database record.
$attach_data = wp_generate_attachment_metadata( $attach_id, $filename );
wp_update_attachment_metadata( $attach_id, $attach_data );
// set the featured image
update_post_meta($post_id, \'_thumbnail_id\', $attach_id);
}
}
}
