%tag% in permalink not working

Question

I use custom permalink structure:

/%tag%/%postname%/

and it is not working. I get url - http://mydomain.com/%tag%/post/. So there is no tag name, just %tag%. If i place %category% instead ot %tag%, everithing is ok.

Can somebody solve this problem?

Answer 1

I got the following code to work in WP 3.0.1 and WP 3.1 RC 2, but with an important difference. Before 3.1, the tag structure is explicitly defined as %tag%, but in 3.1 this becomes %post_tag%. So my code handles both situations. It adds a hook to get_permalink() and inserts a tag if needed.

define( 'WPSE_7004_DEFAULT_TAG', 'untagged' );
if ( version_compare( $wp_version, '3.0.9' ) <= 0 ) {
    // This is pre-3.1
    define( 'WPSE_7004_TAG_STRUCT', '%tag%' );
} else {
    define( 'WPSE_7004_TAG_STRUCT', '%post_tag%' );
}

add_filter( 'post_link', 'wpse7004_post_link', 10, 3 );
function wpse7004_post_link( $permalink, $post, $leavename )
{
    if ( FALSE !== strpos( $permalink, WPSE_7004_TAG_STRUCT ) ) {
        $tags = get_the_tags( $post->ID );
        if ( $tags ) {
            usort( $tags, '_usort_terms_by_ID' );
            $tag = $tags[0]->slug;
        } else {
            // No tag. Use default tag name, otherwise rewrite rule matching goes wrong.
            $tag = WPSE_7004_DEFAULT_TAG;
        }
        $permalink = str_replace( WPSE_7004_TAG_STRUCT, $tag, $permalink );
    }

    return $permalink;
}

add_filter( 'request', 'wpse7004_request' );
function wpse7004_request( $query_vars )
{
    if ( array_key_exists( 'tag', $query_vars ) && WPSE_7004_DEFAULT_TAG == $query_vars['tag'] ) {
        unset( $query_vars['tag'] );
    }
    return $query_vars;
}

Answer 2

@Atari asked for a solution.. People who do not have one should not butt in!

I have the same issue. All other %category% %postname% %post_id% etc. resolve fine, but %tag% remains %tag% in the final permalink!

I think it is a bug. I came across a patch which was for an older version. I did not try it yet ( I do not know how to use it either :P ) because I am using the latest version (3.0.4 I think).. but the problem is still there!

I do not want to start the url with %tag% but I need it down the URL. The point is that it should work.. regardless of how I use it!

@Atari if you find a solution please do share it :)

here is the patch I found.. I would appreciate anyone telling me how to use it too :)

*** link-template.php   2009-12-14 05:09:55.000000000 -0500
--- link-template_patched.php   2010-06-21 14:29:24.000000000 -0400
***************
*** 88,93 ****
--- 88,94 ----
                $leavename? '' : '%postname%',
                '%post_id%',
                '%category%',
+         '%tag%',
                '%author%',
                $leavename? '' : '%pagename%',
        );
***************
*** 128,134 ****
--- 129,151 ----
                                $category = is_wp_error( $default_category ) ? '' : $default_category->slug;
                        }
                }
+
+               if ( strpos($permalink, '%tag%') !== false ) {
+                       $tags = get_the_tags($post->ID);
+
+                       if ( $tags ) {
+                               usort($tags, '_usort_terms_by_ID'); // order by ID
+                               $tag = $tags[0]->slug;
+                       }

+                       // show default tag in permalinks, without
+                       // having to assign it explicitly
+                       if ( empty($tag) ) {
+                               $default_tag = get_tag( get_option( 'default_category' ) );
+                               $tag = is_wp_error( $default_tag ) ? '' : $default_tag->slug;
+                       }
+               }
+
                $author = '';
                if ( strpos($permalink, '%author%') !== false ) {
                        $authordata = get_userdata($post->post_author);
***************
*** 147,152 ****
--- 164,170 ----
                        $post->post_name,
                        $post->ID,
                        $category,
+             $tag,
                        $author,
                        $post->post_name,
                );