Using WordPress ‘pre_term_link’ PHP filter

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apply_filters( 'pre_term_link', string $termlink, WP_Term $term ) is a WordPress PHP filter that allows you to modify the permalink structure of a term before the actual token replacement occurs. This is useful when you want to customize how the term links are generated for your website.

Usage

To use this filter, you need to add it to your theme’s functions.php file or a custom plugin. Here’s a code example:

function custom_pre_term_link( $termlink, $term ) {
    // Your custom code goes here
    return $termlink;
}
add_filter( 'pre_term_link', 'custom_pre_term_link', 10, 2 );

Parameters

  • $termlink (string)
    • The permalink structure for the term’s taxonomy.
  • $term (WP_Term)
    • The term object.

Examples

function add_category_prefix( $termlink, $term ) {
    if ( 'category' === $term->taxonomy ) {
        $termlink = '/prefix' . $termlink;
    }
    return $termlink;
}
add_filter( 'pre_term_link', 'add_category_prefix', 10, 2 );

This code adds a /prefix to the permalink structure of categories. For example, if the original permalink was /category/news, it will become /prefix/category/news.

function remove_taxonomy_base_slug( $termlink, $term ) {
    if ( 'custom_taxonomy' === $term->taxonomy ) {
        $termlink = str_replace( '/custom_taxonomy', '', $termlink );
    }
    return $termlink;
}
add_filter( 'pre_term_link', 'remove_taxonomy_base_slug', 10, 2 );

This code removes the custom taxonomy base slug from its permalinks. If the original permalink was /custom_taxonomy/term, it will become /term.

function make_term_permalink_lowercase( $termlink, $term ) {
    return strtolower( $termlink );
}
add_filter( 'pre_term_link', 'make_term_permalink_lowercase', 10, 2 );

This code changes the term permalinks to lowercase. For example, if the original permalink was /Category/News, it will become /category/news.

function append_term_id( $termlink, $term ) {
    return $termlink . '-' . $term->term_id;
}
add_filter( 'pre_term_link', 'append_term_id', 10, 2 );

This code appends the term ID to the permalink structure. If the original permalink was /category/news, it will become /category/news-123 where 123 is the term ID.

function change_term_permalink_based_on_parent( $termlink, $term ) {
    if ( $term->parent ) {
        $parent_term = get_term( $term->parent, $term->taxonomy );
        $termlink = str_replace( $parent_term->slug, 'parent-' . $parent_term->slug, $termlink );
    }
    return $termlink;
}
add_filter( 'pre_term_link', 'change_term_permalink_based_on_parent', 10, 2 );

This code changes the term permalinks to include a parent taxonomy.