Filter WP posts by tag - PHP

wp-ajax-filter-posts-by-tag.php

<?php

/**
 * Enqueue JS file
 * Be sure to update path to js
 *
 * @link https://gist.github.com/Bobz-zg/16578c3c173abfe2b22daffd67f6f1e0
 * 
 */
function ajax_filter_posts_scripts() {
  // Enqueue script
  wp_register_script('afp_script', get_template_directory_uri() . '/js-folder/ajax-filter-posts.js', false, null, false);
  wp_enqueue_script('afp_script');
 
  wp_localize_script( 'afp_script', 'afp_vars', array(
        'afp_nonce' => wp_create_nonce( 'afp_nonce' ), // Create nonce which we later will use to verify AJAX request
        'afp_ajax_url' => admin_url( 'admin-ajax.php' ),
      )
  );
}
add_action('wp_enqueue_scripts', 'ajax_filter_posts_scripts', 100);


/**
 * Display list fo tags 
 *
 * Place this in a template file
 */
function tags_filter() {
    $tax = 'post_tag';
    $terms = get_terms( $tax );
    $count = count( $terms );
 
    if ( $count > 0 ): ?>
        <div class="post-tags">
        <?php
        foreach ( $terms as $term ) {
            $term_link = get_term_link( $term, $tax );
            echo '<a href="' . $term_link . '" class="tax-filter" title="' . $term->slug . '">' . $term->name . '</a> ';
        } ?>
        </div>
    <?php endif;
}



// Script for getting posts
function ajax_filter_get_posts( $taxonomy ) {
 
  // Verify nonce
  if( !isset( $_POST['afp_nonce'] ) || !wp_verify_nonce( $_POST['afp_nonce'], 'afp_nonce' ) )
    die('Permission denied');
 
  $taxonomy = $_POST['taxonomy'];
 
  // WP Query
  $args = array(
    'tag' => $taxonomy,
    'post_type' => 'post',
    'posts_per_page' => 10,
  );
 
  // If taxonomy is not set, remove key from array and get all posts
  if( !$taxonomy ) {
    unset( $args['tag'] );
  }
 
  $query = new WP_Query( $args );
 
  if ( $query->have_posts() ) : while ( $query->have_posts() ) : $query->the_post(); ?>
 
    <h2><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h2>
    <?php the_excerpt(); ?>
 
  <?php endwhile; ?>
  <?php else: ?>
    <h2>No posts found</h2>
  <?php endif;
 
  die();
}
 
add_action('wp_ajax_filter_posts', 'ajax_filter_get_posts');
add_action('wp_ajax_nopriv_filter_posts', 'ajax_filter_get_posts');