Wordpress: Save data from post meta box. Ignore pesky revisions.

gistfile1.txt

/**
 * Save custom post data meta box
 *
 * @access	function
 * @param	int
 * @return	void
 */
function save_post($post_id) {
	if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) return;
	if (!wp_verify_nonce( $_POST['my_noncename'], MY_PLUGIN_DIRECTORY)) return;
	// Check permissions
	if ( 'page' == $_POST['post_type'] ) {
		if ( !current_user_can( 'edit_page', $post_id ) ) return;
	} else {
		if ( !current_user_can( 'edit_post', $post_id ) ) return;
	}
	if (get_post_type($post_id) == 'revision') return;
	// save data
	update_post_meta($post_id, 'my_value', $_POST['my_value']);
}