在basename wordpress过滤器中不能使用$ 1

Question

Ok this is hard to explain in the heading. But I've made this function in my functions.php

Where i add a title tag to all image links with the image caption. By finding the filename and look it up in the DB, finding the ID and by that getting the correct caption.

Here is the function

add_filter('the_content', 'addshadowboxrel', 12);
add_filter('get_comment_text', 'addshadowboxrel');
function addshadowboxrel ($content) {
  global $wpdb;

    $pattern = "/<a(.*?)href=('|\")([^>]*).(bmp|gif|jpeg|jpg|png)('|\")(.*?)>(.*?)<\/a>/i";
    $path = '$3.$4';
    $attachment_url = basename($path);  

    $attachment_id = $wpdb->get_var( $wpdb->prepare( "SELECT wposts.ID FROM $wpdb->posts wposts, $wpdb->postmeta wpostmeta WHERE wposts.ID = wpostmeta.post_id AND wpostmeta.meta_key = '_wp_attached_file' AND wpostmeta.meta_value = '%s' AND wposts.post_type = 'attachment'", $attachment_url ) );
    $attachment = get_post( $attachment_id );
    $replacement = '<a$1href=$2$3.$4$5 title="'.$attachment->post_excerpt.'" rel="lightbox"$6>$7</a>';
    $content = preg_replace($pattern, $replacement, $content);
    return $content;
}

Everything works: If I replace the $path with the actual path insted of '$3.$4'.

But the basename function dont work as it is here?

Answer 1

Where have you declared $3 and $4? Variable names cannot start with a number. So:

$3
$4

Cannot be valid variables. Can you change them to:

$n3
$n4

Instead? And try! This could be basic but this WOULD be the reason! :)

Also consider using the function preg_match_all. Check out Pattern Syntax for more details.