Contents of a Page widget for Wordpress

page-widget.php

<?php

/*
Plugin Name: Page widget
Description: Use a page as a widget in the sidebar
Author: Jelmer van der Linde
Version: 1.0
Author URI: http://ikhoefgeen.nl
*/

add_action('widgets_init', array('IHG_PageWidget', 'register_widget'));

class IHG_PageWidget extends WP_Widget
{
	public function __construct()
	{
		parent::__construct( false, 'Contents of a page');
	}

	public function widget($args, $instance)
	{
		if (!($page = $this->get_the_page($instance)))
			return;

		printf($args['before_widget'], $args['widget_id'], $args['widget_name']);

		echo apply_filters('the_content', $page->post_content);
		
		echo $args['after_widget'];
	}

	public function update($new_instance, $old_instance)
	{
		$instance = is_array($old_instance)
			? $old_instance
			: array();

		$instance['page_id'] = (int) $new_instance['page_id'];

		return $instance;
	}

	public function form($instance)
	{
		echo '<p>';
		echo '<label for="' . $this->get_field_id('page_id') . '">' . __('Page') . ':</label>';
		wp_dropdown_pages(array(
			'selected' => isset($instance['page_id']) ? $instance['page_id'] : 0,
			'name' => $this->get_field_name('page_id')
		));
		echo '</p>';
	}

	private function get_the_page($instance)
	{
		return !empty($instance['page_id'])
			? get_page($instance['page_id'])
			: null;
	}

	static public function register_widget()
	{
		register_widget(__CLASS__);
	}
}