I was tasked with creating a WordPress site that displays blog posts for different suburbs. Each of these suburbs is required to have its own homepage, with only relevant posts for the suburb listed.
Isn’t that what WordPress Multisite is for?
Each site in a WordPress Multisite network is managed individually. To send a post to another site in the network, you need to use a plugin like Broadcast. For a small number of sites, this is ok. But what if you have hundreds of sites? The answer is obvious. If we use WordPress Multisite, this is going to become really hard to maintain in the long run.
How does it work?
The WordPress permalink structure and rewrite rules will need to be customised in order to make this work. We want to be able to assign posts to taxonomy terms, and have the post list change based on that value.
A default permalink structure might look like this:
/%year%/%monthnum%/%day%/%postname%/
What we need to achieve is:
/%suburb_slug%/%year%/%monthnum%/%day%/%postname%/
The value of %suburb_slug% will be used to limit the posts displayed using the WordPress query.
yoursite.com – displays all posts.
yoursite.com/suburb – displays posts for the suburb.
Just show me the code.
The sample code below can be added to your themes functions.php file. Please be aware that it will not cover all edge cases that you may run into when creating this type of WordPress website.
Remember, whenever you make a change to the permalink structure, you need to save the Permalinks Settings page to flush the rewrite rules.
/**
* @package WordPress
* @subpackage Prepend a Taxonomy to the WordPress Permalink Structure
* @author That Stevens Guy
* @phpcs:disable PSR1.Files.SideEffects
*
* wp-config.php:
* // Add a main suburb for the homepage to the Suburbs taxonomy,
* // define the slug chosen here.
* define('MAIN_SUBURB_SLUG', 'suburb');
* define('DEBUG_REWRITES', false);
*/
/**
* Initialise custom suburb permalink.
* Note: Save permalinks settings page to flush rewrites.
*
* @return void
*/
add_action('init', 'tsg_prepare_permalink');
function tsg_prepare_permalink(): void
{
add_action('parse_request', 'tsg_debug_rewrites');
tsg_add_rewrites();
add_filter('rewrite_rules_array', 'tsg_customise_rewrite_rules_array');
add_filter('request', 'tsg_customise_request_query_vars');
add_action('template_redirect', 'tsg_verify_query_vars');
add_filter('query_vars', 'tsg_add_query_var');
add_filter('available_permalink_structure_tags', 'tsg_add_permalink_structure_tag');
add_filter('page_link', 'tsg_customise_page_link');
add_filter('post_link', 'tsg_customise_link');
add_filter('post_comments_feed_link', 'tsg_customise_link');
add_filter('post_type_link', 'tsg_customise_link');
add_filter('post_type_archive_link', 'tsg_customise_link');
add_filter('term_link', 'tsg_customise_link');
add_filter('author_link', 'tsg_customise_link');
add_filter('day_link', 'tsg_customise_link');
add_filter('month_link', 'tsg_customise_link');
add_filter('year_link', 'tsg_customise_link');
add_filter('feed_link', 'tsg_customise_link');
add_filter('attachment_link', '__return_empty_string');
}
/**
* Add rewrite rules for the query variable %suburb_slug%.
*
* @return void
*/
function tsg_add_rewrites(): void
{
global $wp_rewrite;
$wp_rewrite->set_permalink_structure('/%suburb_slug%/%year%/%monthnum%/%day%/%postname%/');
$wp_rewrite->set_category_base('%suburb_slug%/category');
$wp_rewrite->set_tag_base('%suburb_slug%/tag');
$wp_rewrite->author_base = '%suburb_slug%/' . $wp_rewrite->author_base;
$wp_rewrite->comments_base = '%suburb_slug%/' . $wp_rewrite->comments_base;
$wp_rewrite->date_structure = '%suburb_slug%/%year%/%monthnum%/%day%';
$wp_rewrite->page_structure = '%suburb_slug%/%pagename%';
add_rewrite_tag('%suburb_slug%', '([^/]+)', 'suburb_slug=');
$feedregex = tsg_get_feedregex();
$feedregex2 = tsg_get_feedregex(2);
// Fix root rules.
add_rewrite_rule('^sitemap\.xml$', 'index.php?sitemap=index', 'top');
add_rewrite_rule('^wp-register\.php$', 'index.php?register=true', 'top');
add_rewrite_rule('^wp-app\.php(/.*)?$', 'index.php?error=403', 'top');
add_rewrite_rule('^wp-(atom|rdf|rss|rss2|feed|commentsrss2)\\.php$', 'index.php?feed=old', 'top');
add_rewrite_rule("^$feedregex", 'index.php?feed=$matches[1]', 'top');
add_rewrite_rule("^$feedregex2", 'index.php?feed=$matches[1]', 'top');
add_rewrite_rule("^embed/?$", 'index.php?embed=true', 'top');
add_rewrite_rule('^page/?([0-9]{1,})/?$', 'index.php?paged=$matches[1]', 'top');
add_rewrite_rule("^comments/$feedregex", 'index.php?feed=$matches[1]&withcomments=1', 'top');
add_rewrite_rule("^comments/$feedregex2", 'index.php?feed=$matches[1]&withcomments=1', 'top');
add_rewrite_rule('^comments/embed/?$', 'index.php?pagename=comments&embed=true', 'top');
add_rewrite_rule('([^/]+)/trackback/?$', 'index.php?suburb_slug=$matches[1]&tb=1', 'top');
add_rewrite_rule('([^/]+)(?:/([0-9]+))?/?$', 'index.php?suburb_slug=$matches[1]&page=$matches[2]', 'top');
// Fix %suburb_slug% rules.
add_rewrite_rule('([^/]+)/comments/?$', 'index.php?suburb_slug=$matches[1]&pagename=comments', 'bottom');
add_rewrite_rule('([^/]+)/comments/embed/?$', 'index.php?suburb_slug=$matches[1]&pagename=comments&embed=true', 'bottom');
add_rewrite_rule('([^/]+)/author/?$', 'index.php?suburb_slug=$matches[1]&pagename=author', 'bottom');
add_rewrite_rule('([^/]+)/tag/?$', 'index.php?suburb_slug=$matches[1]&pagename=tag', 'bottom');
add_rewrite_rule('([^/]+)/category/?$', 'index.php?suburb_slug=$matches[1]&pagename=category', 'bottom');
}
/**
* Customise rewrite rules.
*
* @param array $rules
* @return array
*/
function tsg_customise_rewrite_rules_array(array $rules): array
{
$post_types = get_post_types([
'has_archive' => true,
'_builtin' => false
]);
// Custom post types don't apply the filter to replace structure tags
// with regex for the array keys. Substitute our own,
// without changing the array key position.
$is_wrong = false;
foreach ($post_types as $post_type) {
foreach ($rules as $rule => $query) {
if (strpos($rule, "%suburb_slug%/$post_type") !== false) {
$is_wrong = true;
$new_rule = str_replace('%suburb_slug%', '([^/]+)', $rule);
$rules = tsg_replace_key($rules, $rule, $new_rule);
}
}
}
// After the above fix, the queries are messed up, correct them.
if ($is_wrong) {
foreach ($post_types as $post_type) {
foreach ($rules as $rule => $query) {
if (
strpos($rule, "([^/]+)/$post_type") !== false &&
strpos($rule, "([^/]+)/$post_type/category") === false &&
strpos($rule, "([^/]+)/$post_type/([^/]+)") === false &&
strpos($rule, "([^/]+)/$post_type/page/?") === false
) {
if (strpos($rule, $post_type . '/?$') !== false) {
$rules[$rule] =
'index.php?suburb_slug=$matches[1]&post_type=' . $post_type;
} elseif (strpos($rule, '/feed') !== false || strpos($rule, '/(feed') !== false) {
$rules[$rule] =
'index.php?suburb_slug=$matches[1]&post_type=' . $post_type . '&feed=$matches[2]';
} elseif (strpos($rule, '/page') !== false) {
$rules[$rule] =
'index.php?suburb_slug=$matches[1]&post_type=' . $post_type . '&paged=$matches[2]';
}
}
}
}
}
// Remove rewrite rules that don't work,
// or that we can't be bothered dealing with.
$remove_by_rule = [
'amp_',
'type',
'search',
'.*wp-(atom|rdf|rss|rss2|feed|commentsrss2)\\.php$',
'.*wp-app\\.php(/.*)?$',
'.*wp-register.php$'
];
$remove_by_query = [
'attachment',
'?&'
];
foreach ($rules as $rule => $query) {
foreach ($remove_by_rule as $match) {
if (strpos($rule, $match) !== false) {
unset($rules[$rule]);
}
}
foreach ($remove_by_query as $match) {
if (strpos($query, $match) !== false) {
unset($rules[$rule]);
}
}
}
return $rules;
}
/**
* Fix request query variables.
*
* @param array $query_vars
* @return array
*/
function tsg_customise_request_query_vars(array $query_vars): array
{
// Fix canonical redirect and allow root pages.
if (
isset($query_vars['suburb_slug']) &&
!array_key_exists($query_vars['suburb_slug'], tsg_get_all_suburbs_by_slug())
) {
$query_vars['pagename'] = $query_vars['suburb_slug'];
unset($query_vars['suburb_slug']);
}
return $query_vars;
}
/**
* The %suburb_slug%/%pagename% query variable has no effect on the
* 404 status of posts for some reason.
*
* @return void
*/
function tsg_verify_query_vars(): void
{
global $wp_query;
$slug = get_query_var('pagename');
if (
$slug &&
is_single() &&
!array_key_exists($slug, tsg_get_all_suburbs_by_slug())
) {
$wp_query->set_404();
status_header(404);
nocache_headers();
}
}
/**
* Add query variable %suburb_slug%.
*
* @param array $public_query_vars
* @return array
*/
function tsg_add_query_var(array $public_query_vars): array
{
$public_query_vars[] = 'suburb_slug';
return $public_query_vars;
}
/**
* Add the permalink structure tag %suburb_slug% to the admin page.
*
* @param array $tags
* @return array
*/
function tsg_add_permalink_structure_tag(array $tags): array
{
$tags['suburb_slug'] = __('%s (The slug of the Suburb.)');
return $tags;
}
/**
* Replace %suburb_slug% with the current suburb slug.
*
* @param string $link
* @return string
*/
function tsg_customise_link(string $link): string
{
return str_replace('%suburb_slug%', tsg_get_current_suburb_slug(), $link);
}
/**
* Replace main suburb slug with root, or alternate slug if provided.
*
* @param string $link
* @param string $slug
* @return string
*/
function tsg_customise_link_slug(string $link, string $slug = '/'): string
{
$slug = $slug !== '/' ? "/$slug/" : $slug;
return str_replace('/' . MAIN_SUBURB_SLUG . '/', $slug, $link);
}
/**
* Replace %suburb_slug% and main suburb slug in page links.
*
* @param string $link
* @return string
*/
function tsg_customise_page_link(string $link): string
{
return tsg_customise_link_slug(tsg_customise_link($link));
}
/**
* Grab the slug of the current suburb.
*
* @param bool $echo
* @return string|void
*/
function tsg_get_current_suburb_slug(bool $echo = false)
{
$slug = MAIN_SUBURB_SLUG;
$query_var = get_query_var('suburb_slug');
if (!empty($query_var) && array_key_exists($query_var, tsg_get_all_suburbs_by_slug())) {
$slug = $query_var;
}
if ($echo) {
echo $slug;
} else {
return $slug;
}
}
/**
* Are we on the main suburb?
*
* @param string $slug
* @return bool
*/
function tsg_is_main_suburb(string $slug = ''): bool
{
if ($slug) {
return $slug === MAIN_SUBURB_SLUG;
}
return tsg_get_current_suburb_slug() === MAIN_SUBURB_SLUG;
}
/**
* Return the current suburb.
*
* @return WP_Term object or false on failure
*/
function tsg_get_current_suburb()
{
return tsg_get_suburb_by_slug(tsg_get_current_suburb_slug());
}
/**
* Retrieve a suburb object by slug.
*
* @param string $slug
* @return WP_Term object or false on failure
*/
function tsg_get_suburb_by_slug(string $slug)
{
$terms = tsg_get_all_suburbs_by_slug();
if (isset($terms[ $slug ])) {
return $terms[ $slug ];
}
return false;
}
/**
* Returns a list of Suburbs in the form of
* [
* term_id => WP_Term {},
* ...
* ]
*
* @return array
*/
function tsg_get_all_suburbs(): array
{
$result = get_option('tsg_suburbs');
if (!$result) {
$terms = get_terms('suburb', [ 'hide_empty' => false ]);
if (empty($terms) && defined('MAIN_SUBURB_SLUG')) {
wp_insert_term(MAIN_SUBURB_SLUG, 'suburb');
$terms = get_terms([
'taxonomy' => 'suburb',
'hide_empty' => false
]);
}
$result = [];
foreach ($terms as $term) {
$result[ $term->term_id ] = $term;
}
update_option('tsg_suburbs', $result, false);
}
return $result;
}
/**
* Returns a list of Suburbs in the form of
* [
* term_slug => WP_Term {},
* ...
* ]
*
* @return array
*/
function tsg_get_all_suburbs_by_slug(): array
{
$result = get_option('tsg_suburbs_by_slug');
if (!$result) {
$terms = tsg_get_all_suburbs();
$result = [];
foreach ($terms as $term) {
$result[ $term->slug ] = $term;
}
update_option('tsg_suburbs_by_slug', $result, false);
}
return $result;
}
/**
* Clear cached suburb lists.
*
* @return void
*/
add_action('edited_suburb', 'tsg_update_suburb', 11);
add_action('create_suburb', 'tsg_update_suburb', 11);
function tsg_update_suburb(): void
{
delete_option('tsg_suburbs');
delete_option('tsg_suburbs_by_slug');
if (function_exists('w3tc_flush_all')) {
w3tc_flush_all();
}
}
/**
* Register Suburbs taxonomy.
*
* @return @void
*/
add_action('after_setup_theme', function (): void {
register_taxonomy(
'suburb',
[ 'post' ],
[
'label' => 'Suburbs',
'labels' => [
'name' => 'Suburbs',
'singular_name' => 'Suburb',
'add_new' => 'Add New',
'add_new_item' => 'Add New Suburb',
'edit_item' => 'Edit Suburb',
'new_item' => 'New Suburb',
'view_item' => 'View Suburb',
'search_items' => 'Search Suburbs',
'not_found' => 'Nothing Found',
'not_found_in_trash' => 'Nothing found in the Trash',
'parent_item_colon' => ''
],
'publicly_queryable' => false,
'has_archive' => false,
'rewrite' => false,
'hierarchical' => true,
'show_in_nav_menus' => false,
'show_tagcloud' => false,
'show_admin_column' => false,
'capabilities' => [ 'assign_terms' => 'edit_posts' ],
'show_in_rest' => true
]
);
});
/**
* Limit posts to just those for the current suburb.
*
* @param WP_Query $query Query object before WP_Query is called.
* @return WP_Query
*/
add_action('pre_get_posts', 'tsg_pre_get_posts');
function tsg_pre_get_posts(WP_Query $query): WP_Query
{
if ($query->is_admin) {
return $query;
}
// Bypass this entirely for menus.
if (
isset($query->query[ 'post_type' ]) &&
$query->query[ 'post_type' ] === 'nav_menu_item'
) {
return $query;
}
$suburb = tsg_get_current_suburb();
if (empty($suburb)) {
$query->set('pagename', '');
$query->set_404();
status_header(404);
nocache_headers();
return $query;
}
// Main suburb sees all posts.
if (tsg_is_main_suburb($suburb->slug)) {
return $query;
}
// Apply the tax query.
$query->set('tax_query', [
'relation' => 'AND',
[
'taxonomy' => 'suburbs',
'field' => 'slug',
'include_children' => false,
'terms' => [ tsg_get_current_suburb_slug() ],
'operator' => 'IN'
]
]);
return $query;
}
/**
* Debug rewrite rules.
* Based on: https://gist.github.com/adamrosloniec/e34fcc7a0743769c75db1b072d677946
*
* @param WP $query
* @return void
*/
function tsg_debug_rewrites(WP $query): void
{
global $wp_rewrite, $wp_post_types, $wp_taxonomies;
if (empty(DEBUG_REWRITES)) {
return;
}
if (is_admin() || !is_user_logged_in()) {
return;
}
echo '<p><strong>--- START REWRITE DEBUG ---</strong></p>';
echo '<h2>Rewrite Rules</h2><table style="font-size:1em;">' .
'<tr><th align="left">Rule</th><th align="left">Query</th></tr>';
foreach ($wp_rewrite->wp_rewrite_rules() as $rule => $match) {
$rewrite_bg = $rule === $query->matched_rule ? 'style="background:yellow;"' : '';
echo "<tr $rewrite_bg><td>" .
var_export($rule, true) . "</td><td>$match</td></tr>";
}
echo '</table>';
echo '<h2>Permalink Structure</h2><table style="font-size:1em;">' .
'<tr><th align="left" colspan="2">Post Type</th></tr>' .
'<tr><td>Page</td><td>' . $wp_rewrite->get_page_permastruct() . '</td></tr>' .
"<tr><td>Post</td><td>$wp_rewrite->permalink_structure</td></tr>";
foreach ($wp_post_types as $post_type) {
if (
!empty($post_type->name) &&
!empty($post_type->label) &&
// @phpstan-ignore-next-line
!empty($post_type->rewrite['slug'])
) {
$post_type_bg = !empty($query->query_vars['post_type']) &&
$post_type->name === $query->query_vars['post_type']
? 'style="background:yellow;"'
: '';
echo "<tr $post_type_bg><td>$post_type->label</td><td>" .
$post_type->rewrite['slug'] . '</td></tr>';
}
}
echo '<tr><th align="left" colspan="2">Taxonomy</th></tr>';
foreach ($wp_taxonomies as $taxonomy) {
if (
!empty($taxonomy->name) &&
// @phpstan-ignore-next-line
!empty($taxonomy->labels->singular_name) &&
// @phpstan-ignore-next-line
!empty($taxonomy->rewrite['slug'])
) {
$taxonomy_bg = !empty($query->query_vars[$taxonomy->name])
? 'style="background:yellow;"'
: '';
echo "<tr $taxonomy_bg><td>{$taxonomy->labels->singular_name}</td><td>" .
$wp_rewrite->get_extra_permastruct($taxonomy->name) . '</td></tr>';
}
}
echo '<tr><th align="left" colspan="2">Archive</th></tr>';
$author_bg = !empty($query->query_vars['author_name']) ? 'style="background:yellow;"' : '';
echo "<tr $author_bg><td>Author</td><td>" .
$wp_rewrite->get_author_permastruct() . '</td></tr>';
$date_bg = !empty($query->query_vars['author_name']) ? 'style="background:yellow;"' : '';
echo "<tr $date_bg><td>Date</td><td>" .
$wp_rewrite->get_date_permastruct() . '</td></tr>';
echo '<tr><th align="left" colspan="2">Feed</th></tr>';
echo "<tr><td>Feed</td><td>" .
$wp_rewrite->get_feed_permastruct() . '</td></tr>';
echo "<tr><td>Comments</td><td>" .
$wp_rewrite->get_comment_feed_permastruct() . '</td></tr>';
echo '</table>';
echo '<h2>Request</h2><p>' .
var_export($query->request, true) . '</p>';
$matched_bg = !empty($query->matched_rule) ? 'style="background:yellow;"' : '';
echo "<h2>Matched Rewrite Rule</h2><p $matched_bg>" .
var_export($query->matched_rule, true) . '</p>';
echo '<h2>Matched Query</h2><p>' .
var_export($query->matched_query, true) . '</p>';
echo '<h2>Query Variables</h2><p>' .
var_export($query->query_vars, true) . '</p>';
echo '<p><strong>--- END REWRITE DEBUG ---</strong></p>';
}
/**
* Build a regex to match the feed section of URLs, something like (feed|atom|rss|rss2)/?
* Based on: https://github.com/WordPress/WordPress/blob/master/wp-includes/class-wp-rewrite.php#L873
*
* @param int $version
* @return string
*/
function tsg_get_feedregex(int $version = 1): string
{
global $wp_rewrite;
$feedregex2 = '';
foreach ((array)$wp_rewrite->feeds as $feed_name) {
$feedregex2 .= $feed_name . '|';
}
$feedregex2 = '(' . trim($feedregex2, '|') . ')/?$';
if ($version === 2) {
return $feedregex2;
}
/*
* $feedregex is identical but with /feed/ added on as well, so URLs like <permalink>/feed/atom
* and <permalink>/atom are both possible
*/
return $wp_rewrite->feed_base . '/' . $feedregex2;
}
/**
* Replace an array key without changing the array key position.
* Based on: https://stackoverflow.com/a/8884153
*
* @param array $array
* @return array
*/
function tsg_replace_key(array $array, $old_key, $new_key): array
{
$keys = array_keys($array);
$index = array_search($old_key, $keys, true);
if ($index === false) {
return $array;
}
$keys[$index] = $new_key;
return array_combine($keys, array_values($array));
}
https://gist.github.com/ThatStevensGuy/39e92db4d38c8b763f55856f38e9f3e0
Performance Issues
The results of all suburb taxonomy terms are stored in a WordPress option. WordPress options are cached for fast retrieval. If you combine W3 Total Cache with dynamic content caching, such as Cloudflare APO, you should have no performance issues.
Custom Post Types
The current version of WordPress (5.7.2) does not apply a filter to replace permalink structure tags with regex for custom post types. I have provided a filter in the sample code that corrects this issue.