sf-pro-filters.php

<?php
// * Search & Filter Pro filters
// Limit taxonomy term dropdowns to terms associated with the form's specified post type(s)
// cf https://gist.github.com/rmorse/7b59b45a14b1ca179868#file-sf-pro-filter-input-object-php
function example_filter_input_object( $input_object, $sfid ) {
	
	if ( ( !in_array( $input_object['name'], array( '_sft_one', '_sft_two', '_sft_three' ) ) ) )
		return $input_object;
	
	// make sure the options variable actually exists (it's only available to certain field types)
	if ( !isset( $input_object['options'] ) )
		return $input_object;
	
	if ( '_sft_one' == $input_object['name'] )
		$taxonomy = 'one';
	if ( '_sft_two' == $input_object['name'] )
		$taxonomy = 'two';
	if ( '_sft_three' == $input_object['name'] )
		$taxonomy = 'three';
		
	$meta_key = '';
	
	// get the taxonomy terms we want, then get all their ancestors (array of slugs)
	$limited_terms = example_get_terms_by_post_type( $taxonomy, $post_type, $meta_key );
	if ( is_taxonomy_hierarchical( $taxonomy ) )
		$limited_terms = example_get_terms_parents( $limited_terms, $taxonomy );
	
	$new_options = $sticky_options = array();
	
	// set up terms that will stick to the top of the list
	$sticky_slugs = array( 'online', 'all-states' );
	
	// get the "all items" option first
	$sticky_options[] = array_shift( $input_object['options'] );
	
	foreach ( $input_object['options'] as $option ) {
		if ( in_array( $option->value, $limited_terms ) ) {
			if ( in_array( $option->value, $sticky_slugs ) )
				$sticky_options[] = $option;
			else
				$new_options[] = $option;
		}
	}
	
	$new_options = array_merge( $sticky_options, $new_options );
	
	// TESTING
	/*
	if ( current_user_can('manage_options') ) {
		//echo '<p>Original input object: </p>';
		//var_dump( $input_object );
		
		echo '<p>New options: </p>';
		var_dump( $new_options );
		
		echo '<p>Desired Terms: </p>';
		var_dump( $limited_terms );
	}
	/**/
	
	// ditch all the old options
	unset( $input_object['options'] );
	
	// replace with our new list
	$input_object['options'] = $new_options;
	
	return $input_object;
}
add_filter( 'sf_input_object_pre', 'example_filter_input_object', 10, 2 );


// get an array of taxonomy term slugs associated with a specific post type (for shared taxonomies)
function example_get_terms_by_post_type( $taxonomies, $post_types, $meta_key = NULL ) {
	
	$transient = 'limited_terms_' . $taxonomies . '_for_' . $post_types;
	if ( !empty( $meta_key ) )
		$transient .= '_and_' . $meta_key;
	$transient = sanitize_key( $transient );
	
	// Get any existing copy of our transient data
	if ( false === ( $terms_for_post_type = get_transient( $transient ) ) ) {
	    global $wpdb;
		$meta_join = $meta_and = '';
		if ( !empty( $meta_key ) ) {
			$meta_join = "INNER JOIN $wpdb->postmeta AS pm ON pm.post_id = p.ID";
			$meta_and = sprintf( "AND pm.meta_key = '%s'", $meta_key );
		}
	    $query = $wpdb->prepare(
	        "SELECT t.slug from $wpdb->terms AS t
	        INNER JOIN $wpdb->term_taxonomy AS tt ON t.term_id = tt.term_id
	        INNER JOIN $wpdb->term_relationships AS r ON r.term_taxonomy_id = tt.term_taxonomy_id
	        INNER JOIN $wpdb->posts AS p ON p.ID = r.object_id
			$meta_join
	        WHERE p.post_type IN('%s') AND tt.taxonomy IN('%s')
			$meta_and
	        GROUP BY t.term_id",
	        $post_types,
	        $taxonomies
	    );
	
	
	     $terms_for_post_type = $wpdb->get_col( stripslashes( $query ) );
	     set_transient( $transient, $terms_for_post_type, HOUR_IN_SECONDS / 2 );
	}
	
    return $terms_for_post_type;
}


// restore parent/child hierarchies after cherry-picking child terms
function example_get_terms_parents( $limited_terms, $taxonomy ) {
	
	$parent_slugs = array();
	foreach ( $limited_terms as $child_term ) {
		$term_obj = get_term_by( 'slug', $child_term, $taxonomy );
		$parent_ids = get_ancestors( $term_obj->term_id, $taxonomy );
		foreach ( $parent_ids as $id ) {
			$parent_term = get_term_by( 'id', $id, $taxonomy );
			$parent_slugs[] = $parent_term->slug;
		}
	}
	
	return array_merge( $limited_terms,  $parent_slugs );
}