求WordPress文章中匹配指定域名URL的PHP函数

Hey there! I’ve put together a PHP solution tailored exactly for your WordPress use case—this will grab the first URL in a post’s content that starts with your specified domain, then let you output it right where you need it (like right after the post title).

Step 1: Add the Reusable Function to Your Theme #

Drop this into your theme’s functions.php file. It’s built to play nice with WordPress’s loop and handle edge cases:

/**
 * Fetch the first URL in a WordPress post that matches a target domain
 * @param string $target_domain Full domain to match (e.g., 'https://example.com')
 * @return string|null Matching URL, or null if no match exists
 */
function get_first_matching_domain_url($target_domain) {
    global $post;
    
    // Exit early if we're not in the WordPress loop or post has no content
    if (!isset($post) || empty($post->post_content)) {
        return null;
    }
    
    $post_content = $post->post_content;
    // Escape special regex characters (like dots) in the target domain
    $escaped_domain = preg_quote(rtrim($target_domain, '/'), '/');
    
    // Regex pattern to match URLs starting with the target domain
    // Captures until whitespace, quotes, or angle brackets (covers plain text and HTML links)
    $pattern = "/https?:\/\/{$escaped_domain}[^\s\"'>]+/i";
    
    // Grab the first matching URL
    if (preg_match($pattern, $post_content, $matches)) {
        return $matches[0];
    }
    
    return null;
}

Step 2: Output the URL in Your Template #

Let’s say you want to display the URL right after the post title in your single.php template. Add this code in the appropriate spot inside the WordPress loop:

<?php
// Replace with your actual target domain
$target_domain = 'https://example.com';
$matching_url = get_first_matching_domain_url($target_domain);

if ($matching_url) {
    // Customize the HTML to fit your theme's styling
    echo '<div class="post-related-url">';
    echo 'Check out this resource: <a href="' . esc_url($matching_url) . '" rel="noopener">' . esc_html($matching_url) . '</a>';
    echo '</div>';
} else {
    // Optional: Show a fallback message if no matching URL was found
    // echo '<div class="post-related-url">No related resource found in this post.</div>';
}
?>

Quick Tips to Keep in Mind #

• Loop First: This function depends on the global $post object, so make sure you call it inside the WordPress loop (after while (have_posts()) : the_post();).
• Sanitize Everything: We use esc_url() and esc_html() to sanitize output—always do this in WordPress to avoid XSS vulnerabilities.
• Tweak the Regex: If you need to adjust what counts as the end of a URL (e.g., if your URLs include special characters), modify the [^\s\"'>]+ part of the regex pattern.
• Protocol Precision: Include the full protocol (http:// or https://) in your target domain for accurate matching. If you need to match both, you can adjust the function to handle that, but specificity avoids false matches.

内容的提问来源于stack exchange，提问作者orichec1000