I’ll build this as a strong inc/ajax/filter-posts.php module for your RX theme: secure AJAX + REST support, taxonomy/meta/search/date filters, sorting, pagination, layout switching, nonce checks, sanitization, and JSON responses.
Below is an advanced, complete inc/ajax/filter-posts.php file for your RX Theme.
It includes:
AJAX post filtering, REST API endpoint, nonce security, category/tag/taxonomy filters, meta filters, date filters, search, author filter, pagination, load more, sorting, layout support, excerpt/image/schema helpers, cache support, and safe sanitization.
Create this file:
rx-theme/inc/ajax/filter-posts.phpThen paste this code:
<?php
/**
* RX Theme - Advanced AJAX / REST Post Filtering
*
* File: inc/ajax/filter-posts.php
*
* Features:
* - WordPress AJAX post filtering
* - REST API filtering endpoint
* - Nonce security
* - Category, tag, author, taxonomy filters
* - Meta query filters
* - Date query filters
* - Search query support
* - Post type support
* - Pagination and load more
* - Multiple layouts: grid, list, card, minimal
* - Sort by date, title, modified, comment count, menu order, random, meta value
* - Sticky post control
* - Featured image support
* - Reading time support
* - Schema-friendly output
* - Object cache support
* - Clean JSON response
*
* @package RX_Theme
*/
if ( ! defined( 'ABSPATH' ) ) {
exit;
}
if ( ! class_exists( 'RX_Ajax_Filter_Posts' ) ) :
final class RX_Ajax_Filter_Posts {
/**
* AJAX action name.
*/
const AJAX_ACTION = 'rx_filter_posts';
/**
* Nonce action.
*/
const NONCE_ACTION = 'rx_filter_posts_nonce_action';
/**
* Nonce field name.
*/
const NONCE_NAME = 'nonce';
/**
* REST namespace.
*/
const REST_NAMESPACE = 'rx-theme/v1';
/**
* REST route.
*/
const REST_ROUTE = '/filter-posts';
/**
* Cache group.
*/
const CACHE_GROUP = 'rx_filter_posts';
/**
* Constructor.
*/
public function __construct() {
add_action( 'wp_ajax_' . self::AJAX_ACTION, array( $this, 'ajax_filter_posts' ) );
add_action( 'wp_ajax_nopriv_' . self::AJAX_ACTION, array( $this, 'ajax_filter_posts' ) );
add_action( 'rest_api_init', array( $this, 'register_rest_route' ) );
add_action( 'wp_enqueue_scripts', array( $this, 'localize_filter_data' ), 20 );
}
/**
* Register REST endpoint.
*/
public function register_rest_route() {
register_rest_route(
self::REST_NAMESPACE,
self::REST_ROUTE,
array(
'methods' => WP_REST_Server::READABLE,
'callback' => array( $this, 'rest_filter_posts' ),
'permission_callback' => '__return_true',
'args' => $this->get_rest_args(),
)
);
}
/**
* REST args.
*
* @return array
*/
private function get_rest_args() {
return array(
'post_type' => array(
'type' => 'string',
'default' => 'post',
'sanitize_callback' => 'sanitize_key',
),
'page' => array(
'type' => 'integer',
'default' => 1,
'sanitize_callback' => 'absint',
),
'per_page' => array(
'type' => 'integer',
'default' => 10,
'sanitize_callback' => 'absint',
),
'search' => array(
'type' => 'string',
'default' => '',
'sanitize_callback' => 'sanitize_text_field',
),
'category' => array(
'type' => 'string',
'default' => '',
'sanitize_callback' => 'sanitize_text_field',
),
'tag' => array(
'type' => 'string',
'default' => '',
'sanitize_callback' => 'sanitize_text_field',
),
'author' => array(
'type' => 'integer',
'default' => 0,
'sanitize_callback' => 'absint',
),
'orderby' => array(
'type' => 'string',
'default' => 'date',
'sanitize_callback' => 'sanitize_key',
),
'order' => array(
'type' => 'string',
'default' => 'DESC',
'sanitize_callback' => 'sanitize_key',
),
);
}
/**
* Localize data for frontend scripts.
*
* This assumes your main theme JS handle is rx-theme-main.
* Change the handle if your enqueue.php uses another name.
*/
public function localize_filter_data() {
$handle = apply_filters( 'rx_filter_posts_script_handle', 'rx-theme-main' );
if ( wp_script_is( $handle, 'enqueued' ) || wp_script_is( $handle, 'registered' ) ) {
wp_localize_script(
$handle,
'rxFilterPosts',
array(
'ajaxUrl' => admin_url( 'admin-ajax.php' ),
'restUrl' => esc_url_raw( rest_url( self::REST_NAMESPACE . self::REST_ROUTE ) ),
'nonce' => wp_create_nonce( self::NONCE_ACTION ),
'action' => self::AJAX_ACTION,
'loadingText' => esc_html__( 'Loading posts...', 'rx-theme' ),
'noPostsText' => esc_html__( 'No posts found.', 'rx-theme' ),
'errorText' => esc_html__( 'Something went wrong. Please try again.', 'rx-theme' ),
)
);
}
}
/**
* AJAX callback.
*/
public function ajax_filter_posts() {
$this->verify_ajax_nonce();
$params = $this->sanitize_request_params( $_POST );
$data = $this->get_filtered_posts_response( $params );
wp_send_json( $data );
}
/**
* REST callback.
*
* @param WP_REST_Request $request REST request.
* @return WP_REST_Response
*/
public function rest_filter_posts( WP_REST_Request $request ) {
$params = $this->sanitize_request_params( $request->get_params() );
$data = $this->get_filtered_posts_response( $params );
return rest_ensure_response( $data );
}
/**
* Verify AJAX nonce.
*/
private function verify_ajax_nonce() {
$nonce = isset( $_POST[ self::NONCE_NAME ] )
? sanitize_text_field( wp_unslash( $_POST[ self::NONCE_NAME ] ) )
: '';
if ( ! wp_verify_nonce( $nonce, self::NONCE_ACTION ) ) {
wp_send_json_error(
array(
'message' => esc_html__( 'Security check failed.', 'rx-theme' ),
),
403
);
}
}
/**
* Sanitize request params.
*
* @param array $input Raw input.
* @return array
*/
private function sanitize_request_params( $input ) {
$input = is_array( $input ) ? wp_unslash( $input ) : array();
$defaults = array(
'post_type' => 'post',
'post_status' => 'publish',
'page' => 1,
'per_page' => 10,
'search' => '',
'category' => '',
'category_id' => 0,
'tag' => '',
'tag_id' => 0,
'author' => 0,
'taxonomy' => '',
'term' => '',
'term_id' => 0,
'tax_relation' => 'AND',
'meta_key' => '',
'meta_value' => '',
'meta_compare' => '=',
'meta_type' => 'CHAR',
'date_after' => '',
'date_before' => '',
'year' => 0,
'month' => 0,
'day' => 0,
'orderby' => 'date',
'order' => 'DESC',
'layout' => 'grid',
'image_size' => 'medium_large',
'excerpt_length' => 24,
'show_excerpt' => true,
'show_image' => true,
'show_author' => true,
'show_date' => true,
'show_category' => true,
'show_comments' => true,
'show_reading_time' => true,
'ignore_sticky_posts' => true,
'include_sticky_posts' => false,
'exclude' => '',
'include' => '',
'offset' => 0,
'load_more' => false,
'cache' => true,
'cache_ttl' => 300,
);
$args = wp_parse_args( $input, $defaults );
$args['post_type'] = $this->sanitize_post_type( $args['post_type'] );
$args['post_status'] = sanitize_key( $args['post_status'] );
$args['page'] = max( 1, absint( $args['page'] ) );
$args['per_page'] = min( 50, max( 1, absint( $args['per_page'] ) ) );
$args['search'] = sanitize_text_field( $args['search'] );
$args['category'] = sanitize_text_field( $args['category'] );
$args['category_id'] = absint( $args['category_id'] );
$args['tag'] = sanitize_text_field( $args['tag'] );
$args['tag_id'] = absint( $args['tag_id'] );
$args['author'] = absint( $args['author'] );
$args['taxonomy'] = sanitize_key( $args['taxonomy'] );
$args['term'] = sanitize_text_field( $args['term'] );
$args['term_id'] = absint( $args['term_id'] );
$args['tax_relation'] = $this->sanitize_relation( $args['tax_relation'] );
$args['meta_key'] = sanitize_key( $args['meta_key'] );
$args['meta_value'] = sanitize_text_field( $args['meta_value'] );
$args['meta_compare'] = $this->sanitize_meta_compare( $args['meta_compare'] );
$args['meta_type'] = $this->sanitize_meta_type( $args['meta_type'] );
$args['date_after'] = sanitize_text_field( $args['date_after'] );
$args['date_before'] = sanitize_text_field( $args['date_before'] );
$args['year'] = absint( $args['year'] );
$args['month'] = absint( $args['month'] );
$args['day'] = absint( $args['day'] );
$args['orderby'] = $this->sanitize_orderby( $args['orderby'] );
$args['order'] = $this->sanitize_order( $args['order'] );
$args['layout'] = $this->sanitize_layout( $args['layout'] );
$args['image_size'] = sanitize_key( $args['image_size'] );
$args['excerpt_length'] = min( 80, max( 5, absint( $args['excerpt_length'] ) ) );
$args['show_excerpt'] = filter_var( $args['show_excerpt'], FILTER_VALIDATE_BOOLEAN );
$args['show_image'] = filter_var( $args['show_image'], FILTER_VALIDATE_BOOLEAN );
$args['show_author'] = filter_var( $args['show_author'], FILTER_VALIDATE_BOOLEAN );
$args['show_date'] = filter_var( $args['show_date'], FILTER_VALIDATE_BOOLEAN );
$args['show_category'] = filter_var( $args['show_category'], FILTER_VALIDATE_BOOLEAN );
$args['show_comments'] = filter_var( $args['show_comments'], FILTER_VALIDATE_BOOLEAN );
$args['show_reading_time'] = filter_var( $args['show_reading_time'], FILTER_VALIDATE_BOOLEAN );
$args['ignore_sticky_posts'] = filter_var( $args['ignore_sticky_posts'], FILTER_VALIDATE_BOOLEAN );
$args['include_sticky_posts'] = filter_var( $args['include_sticky_posts'], FILTER_VALIDATE_BOOLEAN );
$args['exclude'] = $this->sanitize_id_list( $args['exclude'] );
$args['include'] = $this->sanitize_id_list( $args['include'] );
$args['offset'] = absint( $args['offset'] );
$args['load_more'] = filter_var( $args['load_more'], FILTER_VALIDATE_BOOLEAN );
$args['cache'] = filter_var( $args['cache'], FILTER_VALIDATE_BOOLEAN );
$args['cache_ttl'] = min( DAY_IN_SECONDS, max( 60, absint( $args['cache_ttl'] ) ) );
return apply_filters( 'rx_filter_posts_sanitized_params', $args, $input );
}
/**
* Build filtered posts response.
*
* @param array $params Sanitized params.
* @return array
*/
private function get_filtered_posts_response( $params ) {
$cache_key = $this->get_cache_key( $params );
if ( $params['cache'] ) {
$cached = wp_cache_get( $cache_key, self::CACHE_GROUP );
if ( false !== $cached ) {
return $cached;
}
}
$query_args = $this->build_query_args( $params );
$query = new WP_Query( $query_args );
ob_start();
if ( $query->have_posts() ) {
echo '<div class="' . esc_attr( $this->get_wrapper_classes( $params ) ) . '" data-rx-filter-results="true">';
while ( $query->have_posts() ) {
$query->the_post();
$this->render_post_item( get_the_ID(), $params );
}
echo '</div>';
} else {
$this->render_no_posts();
}
$html = ob_get_clean();
$pagination_html = $this->get_pagination_html( $query, $params );
$response = array(
'success' => true,
'html' => $html,
'pagination' => $pagination_html,
'found_posts' => absint( $query->found_posts ),
'max_pages' => absint( $query->max_num_pages ),
'current_page' => absint( $params['page'] ),
'per_page' => absint( $params['per_page'] ),
'has_more' => $params['page'] < $query->max_num_pages,
'next_page' => $params['page'] < $query->max_num_pages ? $params['page'] + 1 : null,
'query_args' => current_user_can( 'manage_options' ) ? $query_args : array(),
'message' => $query->have_posts()
? esc_html__( 'Posts loaded successfully.', 'rx-theme' )
: esc_html__( 'No posts found.', 'rx-theme' ),
);
wp_reset_postdata();
$response = apply_filters( 'rx_filter_posts_response', $response, $query, $params );
if ( $params['cache'] ) {
wp_cache_set( $cache_key, $response, self::CACHE_GROUP, $params['cache_ttl'] );
}
return $response;
}
/**
* Build WP_Query args.
*
* @param array $params Params.
* @return array
*/
private function build_query_args( $params ) {
$args = array(
'post_type' => $params['post_type'],
'post_status' => $params['post_status'],
'paged' => $params['page'],
'posts_per_page' => $params['per_page'],
'ignore_sticky_posts' => $params['ignore_sticky_posts'],
'no_found_rows' => false,
'update_post_meta_cache' => true,
'update_post_term_cache' => true,
);
if ( ! empty( $params['search'] ) ) {
$args['s'] = $params['search'];
}
if ( ! empty( $params['author'] ) ) {
$args['author'] = $params['author'];
}
if ( ! empty( $params['include'] ) ) {
$args['post__in'] = $params['include'];
}
if ( ! empty( $params['exclude'] ) ) {
$args['post__not_in'] = $params['exclude'];
}
if ( ! empty( $params['offset'] ) ) {
$args['offset'] = $params['offset'];
}
if ( $params['include_sticky_posts'] ) {
$sticky_posts = get_option( 'sticky_posts' );
if ( ! empty( $sticky_posts ) ) {
$args['post__in'] = ! empty( $args['post__in'] )
? array_intersect( $args['post__in'], $sticky_posts )
: $sticky_posts;
}
}
$tax_query = $this->build_tax_query( $params );
if ( ! empty( $tax_query ) ) {
$args['tax_query'] = $tax_query;
}
$meta_query = $this->build_meta_query( $params );
if ( ! empty( $meta_query ) ) {
$args['meta_query'] = $meta_query;
}
$date_query = $this->build_date_query( $params );
if ( ! empty( $date_query ) ) {
$args['date_query'] = $date_query;
}
$args = $this->apply_order_args( $args, $params );
return apply_filters( 'rx_filter_posts_query_args', $args, $params );
}
/**
* Build taxonomy query.
*
* @param array $params Params.
* @return array
*/
private function build_tax_query( $params ) {
$tax_query = array();
if ( ! empty( $params['category_id'] ) ) {
$tax_query[] = array(
'taxonomy' => 'category',
'field' => 'term_id',
'terms' => array( $params['category_id'] ),
);
} elseif ( ! empty( $params['category'] ) ) {
$tax_query[] = array(
'taxonomy' => 'category',
'field' => is_numeric( $params['category'] ) ? 'term_id' : 'slug',
'terms' => is_numeric( $params['category'] ) ? array( absint( $params['category'] ) ) : array( sanitize_title( $params['category'] ) ),
);
}
if ( ! empty( $params['tag_id'] ) ) {
$tax_query[] = array(
'taxonomy' => 'post_tag',
'field' => 'term_id',
'terms' => array( $params['tag_id'] ),
);
} elseif ( ! empty( $params['tag'] ) ) {
$tax_query[] = array(
'taxonomy' => 'post_tag',
'field' => is_numeric( $params['tag'] ) ? 'term_id' : 'slug',
'terms' => is_numeric( $params['tag'] ) ? array( absint( $params['tag'] ) ) : array( sanitize_title( $params['tag'] ) ),
);
}
if ( ! empty( $params['taxonomy'] ) && taxonomy_exists( $params['taxonomy'] ) ) {
if ( ! empty( $params['term_id'] ) ) {
$tax_query[] = array(
'taxonomy' => $params['taxonomy'],
'field' => 'term_id',
'terms' => array( $params['term_id'] ),
);
} elseif ( ! empty( $params['term'] ) ) {
$tax_query[] = array(
'taxonomy' => $params['taxonomy'],
'field' => is_numeric( $params['term'] ) ? 'term_id' : 'slug',
'terms' => is_numeric( $params['term'] ) ? array( absint( $params['term'] ) ) : array( sanitize_title( $params['term'] ) ),
);
}
}
if ( count( $tax_query ) > 1 ) {
$tax_query['relation'] = $params['tax_relation'];
}
return $tax_query;
}
/**
* Build meta query.
*
* @param array $params Params.
* @return array
*/
private function build_meta_query( $params ) {
$meta_query = array();
if ( ! empty( $params['meta_key'] ) ) {
$query = array(
'key' => $params['meta_key'],
'compare' => $params['meta_compare'],
'type' => $params['meta_type'],
);
if ( '' !== $params['meta_value'] && 'EXISTS' !== $params['meta_compare'] && 'NOT EXISTS' !== $params['meta_compare'] ) {
$query['value'] = $params['meta_value'];
}
$meta_query[] = $query;
}
/**
* Allows adding complex custom meta query from another file.
*/
$meta_query = apply_filters( 'rx_filter_posts_meta_query', $meta_query, $params );
if ( count( $meta_query ) > 1 && empty( $meta_query['relation'] ) ) {
$meta_query['relation'] = 'AND';
}
return $meta_query;
}
/**
* Build date query.
*
* @param array $params Params.
* @return array
*/
private function build_date_query( $params ) {
$date_query = array();
if ( ! empty( $params['date_after'] ) || ! empty( $params['date_before'] ) ) {
$item = array(
'inclusive' => true,
);
if ( ! empty( $params['date_after'] ) ) {
$item['after'] = $params['date_after'];
}
if ( ! empty( $params['date_before'] ) ) {
$item['before'] = $params['date_before'];
}
$date_query[] = $item;
}
if ( ! empty( $params['year'] ) ) {
$date_query[] = array(
'year' => $params['year'],
);
}
if ( ! empty( $params['month'] ) ) {
$date_query[] = array(
'month' => $params['month'],
);
}
if ( ! empty( $params['day'] ) ) {
$date_query[] = array(
'day' => $params['day'],
);
}
return $date_query;
}
/**
* Apply ordering args.
*
* @param array $args Query args.
* @param array $params Params.
* @return array
*/
private function apply_order_args( $args, $params ) {
$args['order'] = $params['order'];
if ( 'meta_value' === $params['orderby'] || 'meta_value_num' === $params['orderby'] ) {
if ( ! empty( $params['meta_key'] ) ) {
$args['meta_key'] = $params['meta_key'];
$args['orderby'] = $params['orderby'];
} else {
$args['orderby'] = 'date';
}
} else {
$args['orderby'] = $params['orderby'];
}
return $args;
}
/**
* Render one post item.
*
* @param int $post_id Post ID.
* @param array $params Params.
*/
private function render_post_item( $post_id, $params ) {
$classes = array(
'rx-filter-post',
'rx-filter-post--' . $params['layout'],
'post-' . $post_id,
);
if ( has_post_thumbnail( $post_id ) ) {
$classes[] = 'has-post-thumbnail';
} else {
$classes[] = 'no-post-thumbnail';
}
$classes = apply_filters( 'rx_filter_posts_item_classes', $classes, $post_id, $params );
?>
<article <?php post_class( $classes, $post_id ); ?> itemscope itemtype="https://schema.org/Article">
<?php if ( $params['show_image'] ) : ?>
<?php $this->render_post_thumbnail( $post_id, $params ); ?>
<?php endif; ?>
<div class="rx-filter-post__content">
<?php if ( $params['show_category'] ) : ?>
<?php $this->render_post_categories( $post_id ); ?>
<?php endif; ?>
<header class="rx-filter-post__header">
<h2 class="rx-filter-post__title" itemprop="headline">
<a href="<?php echo esc_url( get_permalink( $post_id ) ); ?>" itemprop="url">
<?php echo esc_html( get_the_title( $post_id ) ); ?>
</a>
</h2>
<?php $this->render_post_meta( $post_id, $params ); ?>
</header>
<?php if ( $params['show_excerpt'] ) : ?>
<div class="rx-filter-post__excerpt" itemprop="description">
<?php echo esc_html( $this->get_custom_excerpt( $post_id, $params['excerpt_length'] ) ); ?>
</div>
<?php endif; ?>
<footer class="rx-filter-post__footer">
<a class="rx-filter-post__read-more" href="<?php echo esc_url( get_permalink( $post_id ) ); ?>" aria-label="<?php echo esc_attr( sprintf( __( 'Read more about %s', 'rx-theme' ), get_the_title( $post_id ) ) ); ?>">
<?php esc_html_e( 'Read More', 'rx-theme' ); ?>
</a>
</footer>
</div>
</article>
<?php
}
/**
* Render post thumbnail.
*
* @param int $post_id Post ID.
* @param array $params Params.
*/
private function render_post_thumbnail( $post_id, $params ) {
if ( ! has_post_thumbnail( $post_id ) ) {
return;
}
?>
<figure class="rx-filter-post__thumbnail" itemprop="image" itemscope itemtype="https://schema.org/ImageObject">
<a href="<?php echo esc_url( get_permalink( $post_id ) ); ?>" aria-hidden="true" tabindex="-1">
<?php
echo get_the_post_thumbnail(
$post_id,
$params['image_size'],
array(
'class' => 'rx-filter-post__image',
'loading' => 'lazy',
'decoding' => 'async',
'alt' => esc_attr( get_the_title( $post_id ) ),
)
);
?>
</a>
</figure>
<?php
}
/**
* Render post categories.
*
* @param int $post_id Post ID.
*/
private function render_post_categories( $post_id ) {
$categories = get_the_category( $post_id );
if ( empty( $categories ) || is_wp_error( $categories ) ) {
return;
}
echo '<div class="rx-filter-post__categories">';
foreach ( array_slice( $categories, 0, 2 ) as $category ) {
printf(
'<a class="rx-filter-post__category" href="%1$s">%2$s</a>',
esc_url( get_category_link( $category->term_id ) ),
esc_html( $category->name )
);
}
echo '</div>';
}
/**
* Render post meta.
*
* @param int $post_id Post ID.
* @param array $params Params.
*/
private function render_post_meta( $post_id, $params ) {
if (
! $params['show_author']
&& ! $params['show_date']
&& ! $params['show_comments']
&& ! $params['show_reading_time']
) {
return;
}
echo '<div class="rx-filter-post__meta">';
if ( $params['show_author'] ) {
$author_id = get_post_field( 'post_author', $post_id );
printf(
'<span class="rx-filter-post__author" itemprop="author" itemscope itemtype="https://schema.org/Person">%1$s <a href="%2$s" itemprop="url"><span itemprop="name">%3$s</span></a></span>',
esc_html__( 'By', 'rx-theme' ),
esc_url( get_author_posts_url( $author_id ) ),
esc_html( get_the_author_meta( 'display_name', $author_id ) )
);
}
if ( $params['show_date'] ) {
printf(
'<time class="rx-filter-post__date" datetime="%1$s" itemprop="datePublished">%2$s</time>',
esc_attr( get_the_date( DATE_W3C, $post_id ) ),
esc_html( get_the_date( '', $post_id ) )
);
}
if ( $params['show_reading_time'] ) {
printf(
'<span class="rx-filter-post__reading-time">%s</span>',
esc_html( $this->get_reading_time( $post_id ) )
);
}
if ( $params['show_comments'] && comments_open( $post_id ) ) {
printf(
'<span class="rx-filter-post__comments">%s</span>',
esc_html(
sprintf(
_n(
'%s Comment',
'%s Comments',
get_comments_number( $post_id ),
'rx-theme'
),
number_format_i18n( get_comments_number( $post_id ) )
)
)
);
}
echo '</div>';
}
/**
* Render no posts.
*/
private function render_no_posts() {
?>
<div class="rx-filter-posts-empty">
<h3 class="rx-filter-posts-empty__title">
<?php esc_html_e( 'No posts found', 'rx-theme' ); ?>
</h3>
<p class="rx-filter-posts-empty__text">
<?php esc_html_e( 'Please try another filter, keyword, category, or date range.', 'rx-theme' ); ?>
</p>
</div>
<?php
}
/**
* Get pagination HTML.
*
* @param WP_Query $query Query object.
* @param array $params Params.
* @return string
*/
private function get_pagination_html( $query, $params ) {
if ( $query->max_num_pages <= 1 ) {
return '';
}
if ( $params['load_more'] ) {
if ( $params['page'] >= $query->max_num_pages ) {
return '';
}
return sprintf(
'<button type="button" class="rx-filter-load-more" data-next-page="%1$d">%2$s</button>',
absint( $params['page'] + 1 ),
esc_html__( 'Load More', 'rx-theme' )
);
}
$links = paginate_links(
array(
'base' => '%_%',
'format' => '?paged=%#%',
'current' => max( 1, $params['page'] ),
'total' => $query->max_num_pages,
'type' => 'array',
'prev_text' => esc_html__( 'Previous', 'rx-theme' ),
'next_text' => esc_html__( 'Next', 'rx-theme' ),
)
);
if ( empty( $links ) ) {
return '';
}
return '<nav class="rx-filter-pagination" aria-label="' . esc_attr__( 'Posts pagination', 'rx-theme' ) . '">' . implode( '', $links ) . '</nav>';
}
/**
* Get wrapper classes.
*
* @param array $params Params.
* @return string
*/
private function get_wrapper_classes( $params ) {
$classes = array(
'rx-filter-posts',
'rx-filter-posts--' . $params['layout'],
);
return implode( ' ', array_map( 'sanitize_html_class', $classes ) );
}
/**
* Custom excerpt.
*
* @param int $post_id Post ID.
* @param int $length Word length.
* @return string
*/
private function get_custom_excerpt( $post_id, $length = 24 ) {
$excerpt = get_the_excerpt( $post_id );
if ( empty( $excerpt ) ) {
$content = get_post_field( 'post_content', $post_id );
$content = strip_shortcodes( $content );
$content = wp_strip_all_tags( $content );
$excerpt = $content;
}
return wp_trim_words( $excerpt, $length, '...' );
}
/**
* Reading time.
*
* @param int $post_id Post ID.
* @return string
*/
private function get_reading_time( $post_id ) {
$content = get_post_field( 'post_content', $post_id );
$content = wp_strip_all_tags( strip_shortcodes( $content ) );
$word_count = str_word_count( $content );
$minutes = max( 1, ceil( $word_count / 200 ) );
return sprintf(
_n( '%s min read', '%s min read', $minutes, 'rx-theme' ),
number_format_i18n( $minutes )
);
}
/**
* Cache key.
*
* @param array $params Params.
* @return string
*/
private function get_cache_key( $params ) {
return 'rx_filter_' . md5( wp_json_encode( $params ) );
}
/**
* Sanitize post type.
*
* @param string $post_type Post type.
* @return string
*/
private function sanitize_post_type( $post_type ) {
$post_type = sanitize_key( $post_type );
if ( ! post_type_exists( $post_type ) ) {
return 'post';
}
return $post_type;
}
/**
* Sanitize relation.
*
* @param string $relation Relation.
* @return string
*/
private function sanitize_relation( $relation ) {
$relation = strtoupper( sanitize_key( $relation ) );
return in_array( $relation, array( 'AND', 'OR' ), true ) ? $relation : 'AND';
}
/**
* Sanitize order.
*
* @param string $order Order.
* @return string
*/
private function sanitize_order( $order ) {
$order = strtoupper( sanitize_key( $order ) );
return in_array( $order, array( 'ASC', 'DESC' ), true ) ? $order : 'DESC';
}
/**
* Sanitize orderby.
*
* @param string $orderby Orderby.
* @return string
*/
private function sanitize_orderby( $orderby ) {
$allowed = array(
'none',
'id',
'author',
'title',
'name',
'type',
'date',
'modified',
'parent',
'rand',
'comment_count',
'menu_order',
'meta_value',
'meta_value_num',
'post__in',
);
$orderby = sanitize_key( $orderby );
return in_array( $orderby, $allowed, true ) ? $orderby : 'date';
}
/**
* Sanitize layout.
*
* @param string $layout Layout.
* @return string
*/
private function sanitize_layout( $layout ) {
$allowed = array(
'grid',
'list',
'card',
'minimal',
);
$layout = sanitize_key( $layout );
return in_array( $layout, $allowed, true ) ? $layout : 'grid';
}
/**
* Sanitize meta compare.
*
* @param string $compare Compare.
* @return string
*/
private function sanitize_meta_compare( $compare ) {
$allowed = array(
'=',
'!=',
'>',
'>=',
'<',
'<=',
'LIKE',
'NOT LIKE',
'IN',
'NOT IN',
'BETWEEN',
'NOT BETWEEN',
'EXISTS',
'NOT EXISTS',
'REGEXP',
'NOT REGEXP',
'RLIKE',
);
$compare = strtoupper( trim( $compare ) );
return in_array( $compare, $allowed, true ) ? $compare : '=';
}
/**
* Sanitize meta type.
*
* @param string $type Type.
* @return string
*/
private function sanitize_meta_type( $type ) {
$allowed = array(
'NUMERIC',
'BINARY',
'CHAR',
'DATE',
'DATETIME',
'DECIMAL',
'SIGNED',
'TIME',
'UNSIGNED',
);
$type = strtoupper( sanitize_key( $type ) );
return in_array( $type, $allowed, true ) ? $type : 'CHAR';
}
/**
* Sanitize ID list.
*
* @param mixed $ids IDs.
* @return array
*/
private function sanitize_id_list( $ids ) {
if ( empty( $ids ) ) {
return array();
}
if ( is_string( $ids ) ) {
$ids = explode( ',', $ids );
}
if ( ! is_array( $ids ) ) {
return array();
}
$ids = array_map( 'absint', $ids );
$ids = array_filter( $ids );
return array_values( array_unique( $ids ) );
}
}
endif;
/**
* Initialize RX AJAX filter posts.
*/
function rx_theme_ajax_filter_posts_init() {
return new RX_Ajax_Filter_Posts();
}
rx_theme_ajax_filter_posts_init();
/**
* Helper: frontend filter form shortcode.
*
* Usage:
* [rx_post_filter]
*/
function rx_post_filter_shortcode( $atts ) {
$atts = shortcode_atts(
array(
'post_type' => 'post',
'per_page' => 9,
'layout' => 'grid',
),
$atts,
'rx_post_filter'
);
ob_start();
?>
<div class="rx-post-filter" data-rx-post-filter="true">
<form class="rx-post-filter__form" data-rx-filter-form="true">
<input type="hidden" name="action" value="<?php echo esc_attr( RX_Ajax_Filter_Posts::AJAX_ACTION ); ?>">
<input type="hidden" name="nonce" value="<?php echo esc_attr( wp_create_nonce( RX_Ajax_Filter_Posts::NONCE_ACTION ) ); ?>">
<input type="hidden" name="post_type" value="<?php echo esc_attr( sanitize_key( $atts['post_type'] ) ); ?>">
<input type="hidden" name="per_page" value="<?php echo esc_attr( absint( $atts['per_page'] ) ); ?>">
<input type="hidden" name="layout" value="<?php echo esc_attr( sanitize_key( $atts['layout'] ) ); ?>">
<input type="hidden" name="page" value="1">
<div class="rx-post-filter__row">
<label class="rx-post-filter__label">
<span><?php esc_html_e( 'Search', 'rx-theme' ); ?></span>
<input class="rx-post-filter__input" type="search" name="search" placeholder="<?php esc_attr_e( 'Search posts...', 'rx-theme' ); ?>">
</label>
<label class="rx-post-filter__label">
<span><?php esc_html_e( 'Category', 'rx-theme' ); ?></span>
<select class="rx-post-filter__select" name="category_id">
<option value=""><?php esc_html_e( 'All Categories', 'rx-theme' ); ?></option>
<?php
$categories = get_categories(
array(
'hide_empty' => true,
)
);
foreach ( $categories as $category ) {
printf(
'<option value="%1$d">%2$s</option>',
absint( $category->term_id ),
esc_html( $category->name )
);
}
?>
</select>
</label>
<label class="rx-post-filter__label">
<span><?php esc_html_e( 'Sort By', 'rx-theme' ); ?></span>
<select class="rx-post-filter__select" name="orderby">
<option value="date"><?php esc_html_e( 'Newest', 'rx-theme' ); ?></option>
<option value="title"><?php esc_html_e( 'Title', 'rx-theme' ); ?></option>
<option value="modified"><?php esc_html_e( 'Recently Updated', 'rx-theme' ); ?></option>
<option value="comment_count"><?php esc_html_e( 'Most Commented', 'rx-theme' ); ?></option>
<option value="rand"><?php esc_html_e( 'Random', 'rx-theme' ); ?></option>
</select>
</label>
<label class="rx-post-filter__label">
<span><?php esc_html_e( 'Order', 'rx-theme' ); ?></span>
<select class="rx-post-filter__select" name="order">
<option value="DESC"><?php esc_html_e( 'Descending', 'rx-theme' ); ?></option>
<option value="ASC"><?php esc_html_e( 'Ascending', 'rx-theme' ); ?></option>
</select>
</label>
<button class="rx-post-filter__button" type="submit">
<?php esc_html_e( 'Filter', 'rx-theme' ); ?>
</button>
</div>
</form>
<div class="rx-post-filter__status" data-rx-filter-status="true" aria-live="polite"></div>
<div class="rx-post-filter__results" data-rx-filter-target="true"></div>
<div class="rx-post-filter__pagination" data-rx-filter-pagination="true"></div>
</div>
<?php
return ob_get_clean();
}
add_shortcode( 'rx_post_filter', 'rx_post_filter_shortcode' );Now include it in your functions.php:
/**
* RX AJAX filter posts.
*/
$rx_filter_posts_file = get_template_directory() . '/inc/ajax/filter-posts.php';
if ( file_exists( $rx_filter_posts_file ) ) {
require_once $rx_filter_posts_file;
}You also need frontend JavaScript to make the AJAX form work. Add this to your main JS file, for example:
(function () {
'use strict';
document.addEventListener('DOMContentLoaded', function () {
const filters = document.querySelectorAll('[data-rx-post-filter="true"]');
if (!filters.length || typeof rxFilterPosts === 'undefined') {
return;
}
filters.forEach(function (filterBox) {
const form = filterBox.querySelector('[data-rx-filter-form="true"]');
const target = filterBox.querySelector('[data-rx-filter-target="true"]');
const pagination = filterBox.querySelector('[data-rx-filter-pagination="true"]');
const status = filterBox.querySelector('[data-rx-filter-status="true"]');
if (!form || !target) {
return;
}
const setStatus = function (message) {
if (status) {
status.textContent = message || '';
}
};
const getFormData = function () {
const formData = new FormData(form);
if (!formData.get('nonce')) {
formData.set('nonce', rxFilterPosts.nonce);
}
if (!formData.get('action')) {
formData.set('action', rxFilterPosts.action);
}
return formData;
};
const requestPosts = function (append = false) {
setStatus(rxFilterPosts.loadingText);
const formData = getFormData();
fetch(rxFilterPosts.ajaxUrl, {
method: 'POST',
credentials: 'same-origin',
body: formData
})
.then(function (response) {
if (!response.ok) {
throw new Error('Network response failed.');
}
return response.json();
})
.then(function (data) {
if (!data || data.success === false) {
throw new Error(data?.data?.message || rxFilterPosts.errorText);
}
if (append) {
target.insertAdjacentHTML('beforeend', data.html);
} else {
target.innerHTML = data.html;
}
if (pagination) {
pagination.innerHTML = data.pagination || '';
}
setStatus(data.message || '');
form.dataset.maxPages = data.max_pages || 1;
form.dataset.currentPage = data.current_page || 1;
})
.catch(function (error) {
setStatus(error.message || rxFilterPosts.errorText);
});
};
form.addEventListener('submit', function (event) {
event.preventDefault();
const pageInput = form.querySelector('[name="page"]');
if (pageInput) {
pageInput.value = '1';
}
requestPosts(false);
});
form.addEventListener('change', function () {
const pageInput = form.querySelector('[name="page"]');
if (pageInput) {
pageInput.value = '1';
}
requestPosts(false);
});
if (pagination) {
pagination.addEventListener('click', function (event) {
const loadMore = event.target.closest('.rx-filter-load-more');
if (!loadMore) {
return;
}
event.preventDefault();
const pageInput = form.querySelector('[name="page"]');
if (pageInput) {
pageInput.value = loadMore.dataset.nextPage || '1';
}
requestPosts(true);
});
}
requestPosts(false);
});
});
})();You can use the shortcode anywhere:
[rx_post_filter]Or with options:
[rx_post_filter post_type="post" per_page="12" layout="grid"]For your folder structure, I suggest this:
rx-theme/
└── inc/
└── ajax/
└── filter-posts.phpThis file is ready for your RX Theme and can be expanded later with WooCommerce products, CPT filters, ACF fields, medical article filters, disease category filters, and live search suggestions.