我正在使用上次查看帖子插件的定制版本来抓取我的唱片标签网站上最近查看的发布。

我使用的代码捕获附件图像，但它并不总是页面特征图像-结果是间歇性的。代码如下：

function zg_recently_viewed() { // Output
echo \'<ul style="list-style:none; padding-left:0px;font-size:11px;" class="viewed_posts">\';
if (isset($_COOKIE["WP-LastViewedPosts"])) {
    //echo "Cookie was set.<br/>";  // For bugfixing - uncomment to see if cookie was set
    //echo $_COOKIE["WP-LastViewedPosts"]; // For bugfixing (cookie content)
    $zg_post_IDs = unserialize(preg_replace(\'!s:(\\d+):"(.*?)";!e\', "\'s:\'.strlen(\'$2\').\':\\"$2\\";\'", stripslashes($_COOKIE["WP-LastViewedPosts"]))); // Read serialized array from cooke and unserialize it
    //echo $_COOKIE["WP-LastViewedPosts"];
    foreach ($zg_post_IDs as $value) { // Do output as long there are posts
        global $wpdb;
        $zg_get_title = $wpdb->get_results("SELECT post_title FROM $wpdb->posts WHERE ID = \'$value+0\' AND ID IN ( SELECT object_id FROM $wpdb->term_relationships WHERE term_taxonomy_id = \'5\' ) LIMIT 1");
        $thumb = $wpdb->get_var("SELECT ID FROM $wpdb->posts where post_parent = \'$value\' and post_type = \'attachment\'");
        /* $thumb = $wpdb->get_var( "SELECT meta_value FROM {$wpdb->postmeta} where post_parent = \'$value\' AND meta_key = \'_thumbnail_id\'" ); */
        $thumbnail = wp_get_attachment_image_src($thumb);
        foreach($zg_get_title as $zg_title_out) {
            if ($thumbnail) {
            echo "<li style=\'max-width:96px;float:left;margin-right:20px;min-height:200px;\'><a class=\'relatedimg\' style=\'text-decoration:none;\' href=\\"". get_permalink($value+0) . "\\" title=\\"". $zg_title_out->post_title . "\\"><img src=\'" .$thumbnail[0]. "\' alt=\'Release Image\' />" . $zg_title_out->post_title . "</a></li>\\n";
            } else {
            echo "<li style=\'max-width:96px;float:left;margin-right:20px;min-height:200px;\'><a class=\'relatedimg\' style=\'text-decoration:none;\' href=\\"". get_permalink($value+0) . "\\" title=\\"". $zg_title_out->post_title . "\\"><img src=\'http://vizualrecords.com/wp-content/uploads/2011/04/vizual_feature-150x150.png\' alt=\'Release Image\' />" . $zg_title_out->post_title . "</a></li>\\n";
            }

        }
    }
} else {
    //echo "No cookie found.";  // For bugfixing - uncomment to see if cookie     was not set
}
echo \'</ul>\';

此行：$thumb=$wpdb->get\\u var（“从$wpdb中选择ID->posts，其中post\\u父项=\'value\'，post\\u类型=\'attachment\'”）；

。。。抓取图像，通常会抓取页面的特色图像，但并不总是如此。下面的注释行不起作用，但我认为这更接近我想要的。

cookie是在上面的函数中设置的。请注意，我确实需要通过直接mysql调用（$wpdb）而不是使用普通的WP函数来获取特色图像。

有什么想法吗？