WordPress Widget for recent posts.

cake_recent_posts.php

<?php

/*
Plugin Name: Cake - Recent Posts Widget
Version: 1.0.0
Plugin URI: https://gorm.us/wordpress/plugins/recent-posts
Description: A widget to display recent posts.
Author: Osman Gormus
Author URI: https://gorm.us
*/

add_action('widgets_init', 'cake_recent_posts_init');

/**
 * Initiate the widget.
 */
function cake_recent_posts_init() {
  register_widget('cake_recent_posts');
}

/**
 * Default arguments.
 */
function cake_recent_posts_default_args() {
  $defaults = [
    'title'             => esc_attr__('Recent Posts', 'cake-recent-posts'),
    'title_url'         => '',
    'template'          => '',

    'limit'            => 5,
    'offset'           => 0,
    'order'            => 'DESC',
    'orderby'          => 'date',
    'taxonomy'         => '',
    'post_type'        => ['post'],
    'post_status'      => 'publish',
    'ignore_sticky'    => 1,
    'exclude_current'  => 1,

    'css_class'        => '',
    'before'           => '',
    'after'            => '',
  ];

  // Allow plugins/themes developer to filter the default arguments.
  return apply_filters('cake_recent_posts_defaults', $defaults);
}

/**
 * Get posts.
 */
function cake_recent_posts_get_posts($args = []) {
  // Query arguments.
  $query = [
    'offset'              => $args['offset'],
    'posts_per_page'      => $args['limit'],
    'orderby'             => $args['orderby'],
    'order'               => $args['order'],
    'post_type'           => $args['post_type'],
    'post_status'         => 'publish',
    'ignore_sticky_posts' => $args['ignore_sticky'],
  ];

  // Exclude current post.
  if ($args['exclude_current']) {
    $query['post__not_in'] = [get_the_ID()];
  }

  // Limit posts based on category.
  if (!empty($args['cat'])) {
    $query['category__in'] = $args['cat'];
  }

  // Limit posts based on post tag.
  if (!empty($args['tag'])) {
    $query['tag__in'] = $args['tag'];
  }

  /**
   * Taxonomy query.
   * Prop Miniloop plugin by Kailey Lampert.
   */
  if (!empty($args['taxonomy'])) {
    parse_str($args['taxonomy'], $taxes);

    $operator  = 'IN';
    $tax_query = [];
    foreach (array_keys($taxes) as $k => $slug) {
      $ids = explode(',', $taxes[$slug]);
      if (count($ids) == 1 && $ids['0'] < 0) {
        // If there is only one id given, and it's negative
        // Let's treat it as 'posts not in'
        $ids['0'] = $ids['0'] * -1;
        $operator = 'NOT IN';
      }
      $tax_query[] = [
        'taxonomy' => $slug,
        'field'    => 'id',
        'terms'    => $ids,
        'operator' => $operator
      ];
    }

    $query['tax_query'] = $tax_query;
  }

  // Allow plugins/themes developer to filter the default query.
  $query = apply_filters('cake_recent_posts_default_query_arguments', $query);

  // Perform the query.
  $posts_query = new WP_Query($query);
  if ($posts_query->have_posts()) {
    $template = isset($args['template']) ? $args['template'] : 'template-parts/content/content';
    while ($posts_query->have_posts()) {
      $posts_query->the_post();
      get_template_part($template);
    }
  }
  wp_reset_postdata();
}

class cake_recent_posts extends WP_Widget {

  public function __construct() {
    $widget_details = [
      'classname' => 'cake_recent_posts',
      'description' => 'An advanced widget that gives you total control over the output of your site’s most recent Posts.'
    ];

    parent::__construct('cake_recent_posts', 'Cake Recent Posts', $widget_details);
  }

  public function form($args) {
    $args = wp_parse_args((array) $args, cake_recent_posts_default_args());
    extract($args);
    include('widget_form.php');
  }

  public function update($new_instance, $old_instance) {
    return $new_instance;
  }

	public function widget($instance, $args) {
    $args = wp_parse_args($args, cake_recent_posts_default_args());
    extract($args);
    cake_recent_posts_get_posts($args);
  }

}

widget_form.php

<p>
  <label for="<?php echo $this->get_field_id('title'); ?>">
    <?php _e('Title', 'cake-recent-posts'); ?>
  </label>
  <input class="widefat" id="<?php echo $this->get_field_id('title'); ?>" name="<?php echo $this->get_field_name('title'); ?>" type="text" value="<?php echo esc_attr($args['title']); ?>">
</p>

<div>
  <label>
    <?php _e('Post types', 'cake-recent-posts'); ?>
  </label>
  <ul>
    <?php foreach (get_post_types(array('public' => true), 'objects') as $type) : ?>
      <li>
        <input type="checkbox" value="<?php echo esc_attr($type->name); ?>" id="<?php echo $this->get_field_id('post_type') . '-' . $type->name; ?>" name="<?php echo $this->get_field_name('post_type'); ?>[]" <?php checked(is_array($args['post_type']) && in_array($type->name, $args['post_type'])); ?>>
        <label for="<?php echo $this->get_field_id('post_type') . '-' . $type->name; ?>">
          <?php echo esc_html($type->labels->name); ?>
        </label>
      </li>
    <?php endforeach; ?>
  </ul>
</div>

<p>
  <label for="<?php echo $this->get_field_id('order'); ?>">
    <?php _e('Order', 'cake-recent-posts'); ?>
  </label>
  <select class="widefat" id="<?php echo $this->get_field_id('order'); ?>" name="<?php echo $this->get_field_name('order'); ?>">
    <option value="DESC" <?php selected($args['order'], 'DESC'); ?>><?php _e('Descending', 'rpwe') ?></option>
    <option value="ASC" <?php selected($args['order'], 'ASC'); ?>><?php _e('Ascending', 'rpwe') ?></option>
  </select>
</p>

<p>
  <label for="<?php echo $this->get_field_id('orderby'); ?>">
    <?php _e('Orderby', 'cake-recent-posts'); ?>
  </label>
  <select class="widefat" id="<?php echo $this->get_field_id('orderby'); ?>" name="<?php echo $this->get_field_name('orderby'); ?>">
    <option value="ID" <?php selected($args['orderby'], 'ID'); ?>><?php _e('ID', 'rpwe') ?></option>
    <option value="author" <?php selected($args['orderby'], 'author'); ?>><?php _e('Author', 'rpwe') ?></option>
    <option value="title" <?php selected($args['orderby'], 'title'); ?>><?php _e('Title', 'rpwe') ?></option>
    <option value="date" <?php selected($args['orderby'], 'date'); ?>><?php _e('Date', 'rpwe') ?></option>
    <option value="modified" <?php selected($args['orderby'], 'modified'); ?>><?php _e('Modified', 'rpwe') ?></option>
    <option value="rand" <?php selected($args['orderby'], 'rand'); ?>><?php _e('Random', 'rpwe') ?></option>
    <option value="comment_count" <?php selected($args['orderby'], 'comment_count'); ?>><?php _e('Comment Count', 'rpwe') ?></option>
    <option value="menu_order" <?php selected($args['orderby'], 'menu_order'); ?>><?php _e('Menu Order', 'rpwe') ?></option>
  </select>
</p>

<p>
  <label for="<?php echo $this->get_field_id('limit'); ?>">
    <?php _e('Number of posts to show', 'cake-recent-posts'); ?>
  </label>
  <input class="widefat" id="<?php echo $this->get_field_id('limit'); ?>" name="<?php echo $this->get_field_name('limit'); ?>" type="number" step="1" min="-1" value="<?php echo (int) ($args['limit']); ?>">
</p>

<p>
  <label for="<?php echo $this->get_field_id('offset'); ?>">
    <?php _e('Offset', 'cake-recent-posts'); ?>
  </label>
  <input class="widefat" id="<?php echo $this->get_field_id('offset'); ?>" name="<?php echo $this->get_field_name('offset'); ?>" type="number" step="1" min="0" value="<?php echo (int) ($args['offset']); ?>">
  <small><?php _e('The number of posts to skip', 'cake-recent-posts'); ?></small>
</p>

<p>
  <input class="checkbox" type="checkbox" <?php checked($args['exclude_current'], 1); ?> id="<?php echo $this->get_field_id('exclude_current'); ?>" name="<?php echo $this->get_field_name('exclude_current'); ?>">
  <label for="<?php echo $this->get_field_id('exclude_current'); ?>">
    <?php _e('Exclude current post', 'cake-recent-posts'); ?>
  </label>
</p>

<p>
  <input class="checkbox" type="checkbox" <?php checked($args['ignore_sticky'], 1); ?> id="<?php echo $this->get_field_id('ignore_sticky'); ?>" name="<?php echo $this->get_field_name('ignore_sticky'); ?>" />
  <label for="<?php echo $this->get_field_id('ignore_sticky'); ?>">
    <?php _e('Ignore sticky posts', 'cake-recent-posts'); ?>
  </label>
</p>

<p>
  <label for="<?php echo $this->get_field_id('template'); ?>">
    <?php _e('Template', 'cake-recent-posts'); ?>
  </label>
  <input class="widefat" id="<?php echo $this->get_field_id('template'); ?>" name="<?php echo $this->get_field_name('template'); ?>" type="text" value="<?php echo $args['template']; ?>" placeholder="template-parts/content/content">
  <small><?php _e('Customize the output of each post via a template.<br>See <code>get_template_part()</code>', 'cake-recent-posts'); ?></small>
</p>

<p>
  <label for="<?php echo $this->get_field_id('taxonomy'); ?>">
    <?php _e('Limit to Taxonomy', 'cake-recent-posts'); ?>
  </label>
  <input type="text" class="widefat" id="<?php echo $this->get_field_id('taxonomy'); ?>" name="<?php echo $this->get_field_name('taxonomy'); ?>" value="<?php echo esc_attr($args['taxonomy']); ?>">
  <small><?php _e('Ex: category=1,2,4&amp;post_tag=6,12', 'cake-recent-posts'); ?><br />
    <?php _e('Available: ', 'cake-recent-posts');
    echo implode(', ', get_taxonomies(array('public' => true))); ?></small>
</p>