custom search form widget

gistfile1.aw

<?php 
/*
Custom field search widget
This code adds a widget that allows to search for milepost ranges
*/

// use widgets_init action hook to execute custom function
add_action( 'widgets_init', 'wpyr_milepostwidget_register_widgets' );

 //register our widget
function wpyr_milepostwidget_register_widgets() {
    register_widget( 'wpyr_milepost_widget' );
}

//wpyr_milepost_widget  class
class wpyr_milepost_widget extends WP_Widget {

    //process the new widget
    function wpyr_milepost_widget() {
        $widget_ops = array( 
			'classname' => 'wpyr_milepostwidget_widget_class', 
			'description' => 'Search photos by milepost.' 
			); 
        $this->WP_Widget( 'wpyr_milepost_widget', 'Milepost search Widget', $widget_ops );
    }
 
     //build the widget settings form
    function form($instance) {
        $defaults = array( 'title' => 'Milepost search' ); 
        $instance = wp_parse_args( (array) $instance, $defaults );
        $title = $instance['title'];

        ?>
            <p>Title: <input class="widefat" name="<?php echo $this->get_field_name( 'title' ); ?>"  type="text" value="<?php echo esc_attr( $title ); ?>" /></p>

        <?php
    }
 
    //save the widget settings
    function update($new_instance, $old_instance) {
        $instance = $old_instance;
        $instance['title'] = strip_tags( $new_instance['title'] );
 
        return $instance;
    }
 
    //display the widget
    function widget($args, $instance) {
        extract($args);
 
        echo $before_widget;
        $title = apply_filters( 'widget_title', $instance['title'] );
 
        if ( !empty( $title ) ) { echo $before_title . $title . $after_title; };
		//display search form
		wpyr_search_form();
        echo $after_widget;
    }
}

// Filters the main query on the Image CPT archive. Returns posts in between range of milepost
function wpyr_milepost_query( $query ) {

	global $wp_the_query;

	$start = $_GET['start'];
	$end = $_GET['end'];

	if( (isset($start) && isset($end)) && $wp_the_query === $query && !is_admin() && is_post_type_archive( 'wpyr_image' ) ) {
		$meta_query = array(
			array(
				'key' => '_cmb_wpyr_milepost',
				'value' => array( $start, $end ),
				'type' => 'numeric',
				'compare' => 'BETWEEN'
			)
		);
		$query->set( 'meta_query', $meta_query );
		$query->set( 'orderby', 'menu_order' );
		$query->set( 'meta_key', '_cmb_wpyr_milepost' );
		$query->set( 'order', 'ASC' );
		$query->set( 'posts_per_page', '-1' );
	}

}

add_action( 'pre_get_posts', 'wpyr_milepost_query' );

//Builds the milepost search form
function wpyr_search_form(){ 

?>

	<form name="search" action="" method="get">
		<label for="start">First milepost</label>
		<input id="start" name="start" type="text" />
		<label for="end">Last milepost</label>		
		<input id="end" name="end" type="text" />
		<input type="submit" value="search" />
	</form>
	
<?php 

}
?>