Filter reference

pll_copy_post_metas

Allows plugins to copy post metas when a new post (or page) translation is created or synchronize them. Filter arguments:

  • $metas => an array of post metas
  • $sync => false when copying metas to a new translation, true when synchronizing translations

Example:

add_filter('pll_copy_post_metas', 'copy_post_metas');
function copy_post_metas($metas) {
	return array_merge($metas, array('my_post_meta'));
}

pll_translation_url

Allows plugins to modify (or create) the translation url. This is thus a more generic filter than ‘pll_the_languages_lin’ described below. Filter arguments:

  • $url => the translation URL to modify (set to null if there is no translation available)
  • $slug => the 2-letters language iso-code of the translation

Example (to check if a monthly archive exists in the translated language):

add_filter('pll_translation_url', 'check_archive_translation', 10, 2);
function check_archive_translation($url, $lang) {
	global $wp_query;
	$qv = $wp_query->query;

	if (is_month()) {
		$posts = get_posts(array(
			'lang'     => $lang,
			'year'     => $qv['year'],
			'monthnum' => $qv['monthnum'],
		));
		if (empty($posts))
			return null;
	}
	return $url;
}

Allows plugins to modify the translation link outputed by the language switcher (valid for the widget, the nav menus and the function pll_the_languages). Filter arguments:

  • $url => the translation URL to modify (set to null if there is no translation available)
  • $slug => the 2-letters language iso-code of the translation
  • $locale => the WordPress locale for the language of the translation

Example (to link to the posts list in the right language when there is no translation available):

add_filter('pll_the_language_link', 'my_link', 10, 2);
function my_link($url, $slug) {
return $url === null ? home_url('?lang='.$slug) : $url;
}

Filter : pll_flag_title

Allows plugins to modify the title attribute of the flag in the language switcher (defaults to language name). Filter arguments:

  • $title => the title attribute
  • $slug => the 2-letters language iso-code of the translation
  • $locale => the WordPress locale for the language of the translation

Example:

add_filter('pll_flag_title', 'my_flag_title', 10, 2);
function my_flag_title($title, $slug) {
	switch($slug) {
		case 'en':
			return 'The blog in '.$title;
		break;
		case 'fr':
			return 'Le blog en '.$title;
		break;
		default:
			return $title;
		break;
	}
}

pll_the_languages

Allows plugins to modify the whole output of the language switcher. Filter arguments:

  • $output => the output of the language filter
  • $args => the arguments of the function pll_the_languages

Example (to add a link to the flag file in the title attribute of the dropdown list which maybe useful used together with a script adding a picture in the dropdown):

add_filter('pll_the_languages', 'my_dropdown', 10, 2);
function my_dropdown($output, $args) {
	if (!$args['dropdown'])
		return $output;
	foreach (array('en_US', 'fr_FR', 'de_DE') as $lang) {
		$file = POLYLANG_DIR.”/flags/$lang.png”;
		$value = reset(explode('_', get_locale()));
		$output = str_replace(“value='$value'”,
		“value='$lang' title='$file'”, $output);
	}
	return $output;
}

pll_get_post_types

Allows plugins to modify the list of post types which will be filtered by language. The filter must be added soon in the WordPress loading process: in a function hooked to ‘plugins_loaded’ or directly in functions.php for themes. Filter arguments:

  • $post_types => the array of post type names
  • $hide => true when displaying the list of custom post types in Polylang settings (avoid the user to modify the decision made by the plugin author for a post type)

Example:

add_filter('pll_get_post_types', 'add_cpt_to_pll', 10, 2);
function add_cpt_to_pll($post_types, $hide) {
	if ($hide)
		// hides 'my_cpt' from the list of custom post types in Polylang settings
		unset($post_types['my_cpt']);
	else
		// enables language and translation management for 'my_cpt'
		$post_types['my_cpt'] = 'my_cpt';
	return $post_types;
}

pll_get_taxonomies

Allows plugins to modify the list of taxonomies which will be filtered by language. The default are taxonomies which have the parameter show_ui set to true (which include categories and post tags). The filter must be added soon in the WordPress loading process: in a function hooked to ‘plugins_loaded’ or directly in functions.php for themes. Filter arguments:

  • $taxonomies => the array of taxonomy names
  • $hide => true when displaying the list of custom taxonomies in Polylang settings (avoid the user to modify the decision made by the plugin author for a taxonomy)

Example:

add_filter('pll_get_taxonomies', 'add_tax_to_pll', 10, 2);
function add_tax_to_pll($taxonomies, $hide) {
	if ($hide)
		unset($taxonomies['my_tax']);
	else
		$taxonomies['my_tax'] = 'my_tax';
	return $taxonomies;
}

pll_rewrite_rules

Allows plugins to inform Polylang of a new rewrite rules filter to use (allowing this rules to be filtered by language. Filter arguments:

  • $rules => the array rewrite rules to filter

Example:

// create rewrite rules with a filter 'something_rewrite_rules'
add_filter('generate_rewrite_rules', 'my_rules');
function my_rules($wp_rewrite) {
	$rules[] = ...
	$rules = apply_filters('my_own_rewrite_rules', $rules);
	$wp_rewrite->rules = array_merge(rules, $wp_rewrite->rules);
}
// add the filter (without '_rewrite_rules') to the Polylang list
add_filter('pll_rewrite_rules',
	create_function('$rules',
	'return array_merge($rules, array(\'my_own\'));'));

pll_preferred_language

Allows plugins to modify the visitor preferred language (normally set first by cookie if this is not the first visit, then by the browser preferences). If no preferred language has been found or set by this filter, Polylang fallbacks to the default language. Filter arguments:

  • $slug => language code or false if no preferred language has been found

Example:

// fallback language is English whatever the default language
add_filter('pll_preferred_language', 'my_language_fallback');
function my_language_fallback($slug) {
	return $slug === false ? 'en' : $slug;
}

pll_get_flag

Allows plugins to modify the html output of flags (the images). Filter arguments:

  • $flag => html output of one flag

Example:

// displays language code instead of flags on admin side
add_filter('pll_get_flag', 'no_flag_on_admin');
function no_flag_on_admin($flag) {
	return is_admin() ? '' : $flag;
}

pll_redirect_home

When a visitor reaches the home, Polylang redirects to the home in the correct language. This filter allows plugins to modify the redirected url or prevent this redirection. Filter arguments:

  • $redirect => the redirected url. If set to false, there will be no redirection.

Example:

// prevents home redirection
add_filter('pll_redirect_home', 'no_home_redirection');
function no_home_redirection($redirect) {
	return false;
}