So's WordPress Recommended Posts Widget: displays a customizable list of recommended posts

so-recommended-posts-widget.php

<?php

/**
* Description: So's WordPress Recommended Posts Widget: displays a customizable list of recommended posts
* Author: Ulrich SOSSOU
* Author URI: http://ulrichsossou.com/
* Version: 1.0
* Licence: GPLv2
* Compatibility: WordPress 3.0+
*
*/

/*
Copyright (C) 2010 Ulrich SOSSOU

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/

class SO_Widget_Recommended_Posts extends WP_Widget {

	function SO_Widget_Recommended_Posts() {
		$widget_ops = array('classname' => 'widget_recommended_posts', 'description' => __('A customisable list of recommended posts'));
		$this->WP_Widget('so-recommended-posts', __('Recommended Posts'), $widget_ops);
	}
	
	function sort_posts_by_input( $sortby, $thequery ) {
		return $sortby = "FIND_IN_SET(ID, '" . implode( ',', $thequery->query['post__in'] ) . "')";
	}
	
	function excerpt_length( $length ) {
		return $length = 7;
	}
	
	function excerpt_more( $more ) {
		return $more = '';
	}

	function widget( $args, $instance ) {
		extract($args);
		$title = apply_filters( 'widget_title', empty($instance['title']) ? '' : $instance['title'], $instance, $this->id_base);
		$posts = explode( ',', empty($instance['posts']) ? '' : $instance['posts'] );
		foreach( $posts as $key => $value ) {
			$posts[$key] = trim( $value );
		}
		add_filter( 'posts_orderby', array( &$this, 'sort_posts_by_input' ), 10, 2 );
		$posts_query = new WP_Query( array( 'post__in' => $posts, 'orderby' => 'post__in' ) );
		remove_filter( 'posts_orderby', array( &$this, 'sort_posts_by_input' ) );
		add_filter( 'excerpt_length', array( &$this, 'excerpt_length' ) );
		add_filter( 'excerpt_more', array( &$this, 'excerpt_more' ) );
		echo $before_widget;
		if ( !empty( $title ) ) { echo $before_title . $title . $after_title; } ?>
			<ul class="so-recommended-posts">
				<?php $i = 1; while ( $posts_query->have_posts() ) : $posts_query->the_post();
				echo '<li>';
				if( $i < 4 ) {
					echo '<span class="post-thumb">' . get_the_post_thumbnail() . '</span><span class="post-rank">#' . $i . '</span><span class="post-title"><a href="' . get_permalink() . '">' . get_the_title() . '</a></span>';
				} else {
					echo '<span class="post-rank">' . $i . '.</span><span class="post-title"><a href="' . get_permalink() . '">' . get_the_title() . '</a></span> -- <span class="post-desc">' . get_the_excerpt() . '</span>';
				}
				echo '</li>';
				$i++; endwhile; ?>
			</ul>
		<?php
		echo $after_widget;
		remove_filter( 'excerpt_length', array( &$this, 'excerpt_length' ) );
		remove_filter( 'excerpt_more', array( &$this, 'excerpt_more' ) );
	}

	function update( $new_instance, $old_instance ) {
		$instance = $old_instance;
		$instance['title'] = strip_tags($new_instance['title']);
		$instance['posts'] = strip_tags($new_instance['posts']);
		return $instance;
	}

	function form( $instance ) {
		$instance = wp_parse_args( (array) $instance, array( 'title' => '', 'posts' => '1, 2, 3, 4, 5, 6, 7, 8, 9, 10' ) );
		$title = strip_tags($instance['title']);
		$posts = strip_tags($instance['posts']);
?>
		<p><label for="<?php echo $this->get_field_id('title'); ?>"><?php _e('Title:'); ?></label>
		<input class="widefat" id="<?php echo $this->get_field_id('title'); ?>" name="<?php echo $this->get_field_name('title'); ?>" type="text" value="<?php echo esc_attr($title); ?>" /></p>

		<p><label for="<?php echo $this->get_field_id('posts'); ?>"><?php _e('Posts (enter a comma-separated list of posts IDs):'); ?></label>
		<input class="widefat" id="<?php echo $this->get_field_id('posts'); ?>" name="<?php echo $this->get_field_name('posts'); ?>" type="text" value="<?php echo esc_attr($posts); ?>" /></p>
<?php
	}
}