简单代码给WordPress内容页添加Open Graph标签

如果我们有需要给WordPress添加Open Graph标签的话，我们可以直接在头部添加代码，或者是用 Open Graph 插件，有些SEO插件也是有自带的。对于Open Graph标签来说，谷歌等海外的搜索引擎应该是比较友好的，看很多外贸网站有用到，如果我们有谷歌优化的外贸网站建议还是用上，不管是你用代码还是插件。

实际上，Open Graph 标签较多部分还是添加在内容页，如果我们有需要的话，可以直接设定内容页，当然也可以用判断语句设置home首页。这里找到一段代码还是可用的，是国内的网友修改的。

1、原版代码

/**
* WordPress OG协议 来自 aidiyu
*/
add_action('wp_head', 'starfire',0);
if(!function_exists('starfire')){
  function starfire(){
    
     global $wpdb;
     $post_id = ( null === $post_id ) ? get_the_ID() : $post_id;
     $copy = get_post_meta($post_id , 'author', true);
     if (is_singular() && empty($copy)) {date_default_timezone_set('PRC');echo '
        <meta property="og:type" content="article"/>
        <meta property="article:published_time" content="'.get_the_date('c').'"/>
        <meta property="og:release_date" content="'.get_the_date('c').'"/>
        <meta property="article:author" content="';bloginfo('name'); echo '" />'; echo '
        <meta property="og:author" content="';bloginfo('name');echo '" />'; echo '
        <meta property="og:url" content="';the_permalink(); echo '"/>';        echo '
        <meta property="og:title" content="'.trim(wp_title('',0)).' | '; bloginfo('name'); echo '" />';  echo '
        <meta property="article:published_first" content="';bloginfo('name');echo ',';       the_permalink(); echo '" />
        <meta property="og:description" content="'.get_the_excerpt().'" />
        <meta property="og:image" content="'.get_mypost_thumbnail($post_id).'" />
        <meta itemprop="image" content="' . get_mypost_thumbnail($post_id) . '" />';
    }
  }
}
/**
* WordPress 获取文章摘要整理版 
*/
function get_mypost_excerpt($post_ID,$len){
    if (!function_exists('utf8Substr')) {
        function utf8Substr($str, $from, $len) {
            return preg_replace('#^(?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'.$from.'}'.
                '((?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'.$len.'}).*#s',
                '$1',$str);
        }
    }
    if(!$post_content){
            $post = get_post($post_ID);
            $post_content = $post->post_content;
   }
    if ($post->post_excerpt) {
            $description  = $post->post_excerpt;
    } else {
        if(preg_match('/<p>(.*)<\/p>/iU',trim(strip_tags($post->post_content,"<p>")),$result)){
            $post_content = $result['1'];
        } else {
            $post_content_r = explode("\n",trim(strip_tags($post->post_content)));
            $post_content = $post_content_r['0'];
        }
        $description = utf8Substr($post_content,0,$len);
        return $description;
    }
}
/**
* WordPress 获取文章图片加强版 
*/
function get_mypost_thumbnail($post_ID){
    if (has_post_thumbnail()) {
            $timthumb_src = wp_get_attachment_image_src( get_post_thumbnail_id($post_ID), 'full' ); 
            $url = $timthumb_src[0];
    } else {
        if(!$post_content){
            $post = get_post($post_ID);
            $post_content = $post->post_content;
        }
        preg_match_all('|<img.*?src=[\'"](.*?)[\'"].*?>|i', do_shortcode($post_content), $matches);
        if( $matches && isset($matches[1]) && isset($matches[1][0]) ){       
            $url =  $matches[1][0];
        }else{
            $url =  '';
        }
    }
    return $url;
}

这里还算是比较齐全的，只是设定在内容页。其实大部分无需要这么多的标签，我们可以精简一下。

2、精简版代码

//WordPress OG 协议 cnwper.com 精简版
add_action('wp_head', 'starfire',0);
  function starfire(){
     global $wpdb;
     $post_id = ( null === $post_id ) ? get_the_ID() : $post_id;
     $copy = get_post_meta($post_id , 'author', true);
     if (is_singular() && empty($copy)) {date_default_timezone_set('PRC');echo '
        <meta property="og:type" content="article"/>
        <meta property="og:site_name" content="';bloginfo('name'); echo '" />';  echo '
        <meta property="article:published_time" content="'.get_the_date('c').'"/>
        <meta property="og:url" content="';the_permalink(); echo '"/>';        echo '
        <meta property="og:title" content="'.trim(wp_title('',0)).' - '; bloginfo('name'); echo '" />';  echo '
        <meta property="og:description" content="'.get_the_excerpt().'" />
        <meta property="og:image" content="'.get_mypost_thumbnail($post_id).'" />';
  }
}
/**
* WordPress 获取文章摘要整理版 
*/
function get_mypost_excerpt($post_ID,$len){
    if (!function_exists('utf8Substr')) {
        function utf8Substr($str, $from, $len) {
            return preg_replace('#^(?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'.$from.'}'.
                '((?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'.$len.'}).*#s',
                '$1',$str);
        }
    }
    if(!$post_content){
            $post = get_post($post_ID);
            $post_content = $post->post_content;
   }
    if ($post->post_excerpt) {
            $description  = $post->post_excerpt;
    } else {
        if(preg_match('/<p>(.*)<\/p>/iU',trim(strip_tags($post->post_content,"<p>")),$result)){
            $post_content = $result['1'];
        } else {
            $post_content_r = explode("\n",trim(strip_tags($post->post_content)));
            $post_content = $post_content_r['0'];
        }
        $description = utf8Substr($post_content,0,$len);
        return $description;
    }
}
/**
* WordPress 获取文章图片加强版 
*/
function get_mypost_thumbnail($post_ID){
    if (has_post_thumbnail()) {
            $timthumb_src = wp_get_attachment_image_src( get_post_thumbnail_id($post_ID), 'full' ); 
            $url = $timthumb_src[0];
    } else {
        if(!$post_content){
            $post = get_post($post_ID);
            $post_content = $post->post_content;
        }
        preg_match_all('|<img.*?src=[\'"](.*?)[\'"].*?>|i', do_shortcode($post_content), $matches);
        if( $matches && isset($matches[1]) && isset($matches[1][0]) ){       
            $url =  $matches[1][0];
        }else{
            $url =  '';
        }
    }
    return $url;
}

这里，我只用到几个常用的META标签头部。