Removing leading zeros from custom permalink structure

Question

My WordPress website currently uses this custom permalink structure: %author%/%year%/%monthnum%/%day%/%postname%

In this case, %monthnum% instantiates numbered dates with a leading zero -- e.g., "09" for September. So, a sample URL might look like this:
mywebsite.com/username/2012/09/12/post-name

Is there a function I can add or .htaccess change that I can make which will remove the leading zeros from my permalink stucture? So, using the example above, my URLs would ideally look like this:
mywebsite.com/username/2012/9/12/post-name

Thank you! I've read up on WordPress' structure tags documentation (http://codex.wordpress.org/Using_Permalinks), but I can't find any solutions or plugins for the above-mentioned problem.

Answer 1

How about using custom rewrite tags/structure?

So we'll be using these two rewrite/structure tags:

1. %monthnum2% does the same thing as the %monthnum% tag, but without a leading zero; e.g. 3 and not 03 for March.

2. %day2% does the same thing as the %day% tag, but without a leading zero; e.g. 7 and not 07.

The steps:

1. In the theme functions file (functions.php), add:

   add_action( 'init', function(){
       add_rewrite_tag( '%monthnum2%', '([0-9]{1,2})', 'monthnum=' );
       add_rewrite_tag( '%day2%',      '([0-9]{1,2})', 'day=' );
   } );
   

   That will generate the %monthnum2% and %day2% (rewrite) tags and be used when WordPress (re-)generates the rewrite rules.

   And then add this:

   add_filter( 'post_link', function( $permalink, $post ){
       if ( preg_match( '/%(?:monthnum2|day2)%/', $permalink ) ) {
           $time = strtotime( $post->post_date );
           $date = explode( ' ', date( 'n j', $time ) );
   
           $permalink = str_replace( [
               '%monthnum2%',
               '%day2%',
           ], [
               $date[0],
               $date[1],
           ], $permalink );
   
           $permalink = user_trailingslashit( $permalink, 'single' );
       }
       return $permalink;
   }, 10, 2 );
   

   That will replace the rewrite tags in the permalink.

2. Go to the permalink settings page and then in the "Custom Structure" box, enter this structure: /%year%/%monthnum2%/%day2%/%postname%/ or /%author%/%year%/%monthnum2%/%day2%/%postname%, whichever applies.

   The point is, use %monthnum2% to display the month number without a leading zero and %day2% to display the day number without a leading zero.

3. Save your changes — both the theme functions file and the permalink settings — and go to the "Posts" page (wp-admin/edit.php) and just check everything (mouse-over the post permalink and visit the post).

Answer 2

Filter 'month_link' and 'day_link', WordPress will find the matching posts then without further work.

Sample code:

add_filter( 'month_link', 't5_strip_leading_zeros_in_url' );
add_filter( 'day_link',   't5_strip_leading_zeros_in_url' );

function t5_strip_leading_zeros_in_url( $url )
{
    // no pretty permalinks
    if ( ! $GLOBALS['wp_rewrite']->get_month_permastruct() )
    {
        return $url;
    }

    return str_replace( '/0', '/', $url );
}

Answer 3

htaccess solution

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_URI} ^/.*?/.*?/[0][1-9]/.*?/.*?$
RewriteRule ^(.*?)/(.*?)/[0]([1-9])/ /$1/$2/$3/ [R=301]
</IfModule>

I created a working example for you to test here

What this does is check for the path structure provided if the third path contains, a leading 0 and number 1-9, eg /03/, then applies the rewrite rule to the third-path, leaving the first two paths and additional paths intact (.*?)/(.*?)/. The rule only changes the third path if that path matches (01-09) [0]([1-9]) from eg /03/ to /3/.

Does not affect /uploads/ month images path because the uploads structure does not match the structure provided. Please test using above link to see if it suits your needs.