WP Admin Filters

A modern, Composer-ready WordPress plugin for contextual admin filters on custom post types. Easily add dropdown filters for meta fields, taxonomies, and custom callbacks in the admin post list. Includes Select2 for a better UI.

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✨ Features

• Add filters to the admin list table for any (custom) post type
• Filter by meta fields (auto-discover distinct values or provide options)
• Filter by taxonomies
• Add custom callback filters with your own query logic
• Select2 dropdowns for better usability

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📦 Installation

With Composer (recommended)

composer require jorenrothman/wp-admin-filters

Then activate include the mu-plugin some how.

Manual

1. Download or clone this repository into wp-content/mu-plugins/wp-admin-filters
2. Run composer install inside the plugin folder
3. Activate WP Admin Filters from the WordPress admin

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🚀 Usage

Register filters inside a hook (e.g. plugins_loaded):

use JorenRothman\WpAdminFilters\FilterManager;

add_action('plugins_loaded', static function () {
    $filters = new FilterManager('book'); // post type slug

    // Meta filter: ISBN
    $filters->addMetaFilter('isbn', [
        'label' => 'ISBN',
        'key'   => 'isbn', // meta_key
    ]);

    // Meta filter: Post Object/Relationship Field
    $filters->addMetaFilter('items', [
        'label' => 'Items',
        'key'   => 'items', // meta_key
        'resolve_posts' => true,
    ]);

    // Taxonomy filter: Genre
    $filters->addTaxonomyFilter('genre', [
        'label'    => 'Genre',
        'taxonomy' => 'genre',
    ]);

    // Callback filter: Has Reviews
    $filters->addCallbackFilter('has_reviews', [
        'label' => 'Has Reviews',
        'options' => [
            'yes' => 'Yes',
            'no'  => 'No',
        ],
        'apply' => function (\WP_Query $query, $value) {
            if ($value === 'yes') {
                $query->set('meta_query', [[
                    'key'     => 'review_count',
                    'value'   => 0,
                    'compare' => '>',
                ]]);
            }
            if ($value === 'no') {
                $query->set('meta_query', [[
                    'key'     => 'review_count',
                    'value'   => 0,
                    'compare' => '=',
                ]]);
            }
        },
    ]);

    $filters->register();
});

Now when you visit the Books admin screen, you’ll see the filters above the post list.

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🔧 API Reference

FilterManager::__construct(string $postType)

Create a filter manager for a custom post type.

FilterManager::addMetaFilter(string $key, array $args = [])

Add a meta field filter. Args:

• label (string) – Dropdown label
• key (string) – Meta key (defaults to $key)
• options (array) – Optional predefined key → label pairs. If omitted, distinct values are auto-discovered.
• resolve_posts (bool) - Transform ids into post titles handy for relationship/post object fields.

FilterManager::addTaxonomyFilter(string $key, array $args = [])

Add a taxonomy filter. Args:

• label (string) – Dropdown label
• taxonomy (string) – Taxonomy name

FilterManager::addCallbackFilter(string $key, array $args = [])

Add a custom callback filter. Args:

• label (string) – Dropdown label
• options (array) – Key → label pairs for dropdown options
• apply (callable) – Function fn(WP_Query $query, string $value) that applies custom query logic

FilterManager::register()

Registers the filters (renders the dropdowns and modifies the query).

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🛡 Security

• All incoming request data is sanitized (sanitize_text_field, wp_unslash)
• All HTML output is escaped (esc_attr, esc_html)
• No unsafe direct database queries (only safe $wpdb->prepare when auto-discovering meta values)

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📄 License

MIT License. See LICENSE file for details.

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