I'd been having trouble with the full domain name being written into the path of links and assets. Basically localhost:XXXX works fine, until I try to reach my site from a Virtual Box install of XP or in my local network, where the domain changes to computername.local:XXXX

I managed to solve this problem with a tip from http://www.deluxeblogtips.com/2012/06/relative-urls.html (code below)

The problem is that home_url which is referenced throughout my theme still returns the full domain, rather then just "/" as root. is there a way to filter home_url to do this? yes I could define('WP_HOME', '/' ); which will brute force the path, but causes other issues with feed readers and plugins - it also probably wont work with subdirectory installs.

thanks for your thoughts

add_action( 'template_redirect', 'rw_relative_urls' );
    function rw_relative_urls() {
    // Don't do anything if:
    // - In feed
    // - In sitemap by WordPress SEO plugin
   if ( is_feed() || get_query_var( 'sitemap' ) )
    $filters = array(
     foreach ( $filters as $filter )
    add_filter( $filter, 'wp_make_link_relative' );
    home_url($path = '', $scheme = null);

2 Answers 2


You need to set the WP_HOME and WP_SITEURL in wp-config.php in a smarter way. Like this:

define('WP_HOME', 'http://' . $_SERVER['HTTP_HOST']);
// add the next line if you have a subdirectory install
define('WP_SITEURL', WP_HOME . '/path/to/wordpress');

This will solve your your issues with site URLs as they will be set dynamically on based on whatever the hostname is. This is the correct way to do this -- it's something I do on virtually ever WP install and it's even in the codex. Believe me, you don't really want relative urls.

  • What happens if the site is accessible by both HTTP and HTTPS? Feb 10, 2014 at 22:36
  • 1
    Look at how WP's is_ssl works, use a similar logic in wp-config.php. Feb 10, 2014 at 22:54
  • Thanks. What is the benefit of hard coding the protocol versus using a protocol relative URL? Feb 10, 2014 at 23:00
  • 1
    WP_HOME is used other places than just in links to stylesheets and such -- namely permalinks. You can try it, it just might be a little weird. Specifying a protocol relative WP content URL is usually okay, however. Feb 10, 2014 at 23:14
  • Thanks @chrisguitarguy. After messing around with define('WP_HOME', '/foo'); I realized that it breaks the TinyMCE editor, because the editor isn't smart enough to handle relative URLs to its javascript assets. Feb 11, 2014 at 19:17

home_url calls get_home_url which has the filter home_url:

return apply_filters( 'home_url', $url, $path, $orig_scheme, $blog_id );

see /wp-includes/link-template.php

  • Humm - I've done as much. Basically I revised get_home_url and put it in a functionality plugin, just to see.
    – orionrush
    Jun 24, 2012 at 9:28
  • I revised get_home_url and tried it in a functionality plugin, as wellas in the functions.php of child and parent. function tr_get_home_url( $blog_id = null, $path = '', $scheme = null ) { $orig_scheme = $scheme; $scheme = 'http'; $url = '/'; if ( !empty( $path ) && is_string( $path ) && strpos( $path, '..' ) === false ) $url .= '/'; return apply_filters( 'home_url', $url, $path, $orig_scheme, $blog_id ); } With no effect––So I guess that this would mean that home_url is already being filtered elsewhere in the theme?
    – orionrush
    Jun 24, 2012 at 9:36
  • FYI this query is related to github.com/retlehs/roots/issues/490
    – orionrush
    Jun 24, 2012 at 13:18
  • @orionrush you're not filtering it correctly, you need to attach your filter function to home_url with add_filter. The apply_filter code I gave above is where the filter is actually applied in source.
    – Milo
    Jun 24, 2012 at 13:40

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