SilverStripe 3.1.x Store locator snippet - grabs lat/lng from Google

SS-Store.php

<?php

class Store extends DataObject {

    static $db = array(
        'Title' => "Varchar(128)",
        'Name' => "Varchar(128)",
        'Address1' => "Varchar(128)",
        'Address2' => "Varchar(128)",
        'Address3' => "Varchar(128)",
        'PostCode' => "Varchar(10)",
        "Phone" => "Varchar(16)",
        "Lat" => "Float(10,9)",
        "Lng" => "Float(10,9)"
    );

    private static $summary_fields = array(
        'Title',
        'Name',
        'Address1',
        'Address2',
        'Address3',
        'PostCode',
        'Lat',
        'Lng'
    );


    public function getCMSFields()
    {
        $fields = parent::getCMSFields();

        return $fields;
    }

    public function onBeforeWrite() {

        if (!$this->ID || $this->isChanged()) {
            //get the lat and long values for the address

            //$address = $this->Title ? $this->Title .',' : '';
            $address = $this->Address1 ? $this->Address1 .',' : '';
            $address .= $this->Address2 ? $this->Address2 .',' : '';
            $address .= $this->Address3 ? $this->Address3 .',' : '';
            $address .= $this->PostCode;

            $address = urlencode($address);
            $region = 'GB';


            $json = file_get_contents("http://maps.google.com/maps/api/geocode/json?address=$address&sensor=false&region=$region");

            $lat = $json->{'results'}[0]->{'geometry'}->{'location'}->{'lat'};
            $lng = $json->{'results'}[0]->{'geometry'}->{'location'}->{'lng'};

            if ($lat) {
                $this->Lat = $lat;
            }

            if ($lng) {

                $this->Lng = $lng;
            }


        }

        parent::onBeforeWrite();
    }

}

class StoresService implements WebServiceable {

    public function __construct() {

    }

    public function webEnabledMethods() {
        return array(
            'getStores'		=> 'GET',
        );
    }

    public function getStores($lat = null, $lng = null) {

        /*
         * To find locations in your markers table that are within a certain radius distance of a given latitude/longitude,
         * you can use a SELECT statement based on the Haversine formula. The Haversine formula is used generally for
         * computing great-circle distances between two pairs of coordinates on a sphere.
         *
         * Here's the SQL statement that will find the closest 20 locations that are within a radius of 25 miles to
         * the 37, -122 coordinate. It calculates the distance based on the latitude/longitude of that row and the target
         * latitude/longitude, and then asks for only rows where the distance value is less than 25, orders the whole query
         * by distance, and limits it to 20 results. To search by kilometers instead of miles, replace 3959 with 6371.
         *
         * SELECT id, ( 3959 * acos( cos( radians(37) ) * cos( radians( lat ) ) * cos( radians( lng ) - radians(-122) ) + sin( radians(37) ) * sin( radians( lat ) ) ) ) AS distance
         * FROM tablename
         * HAVING distance < 25
         * ORDER BY distance
         * LIMIT 0 , 20;
         * */


        if (is_numeric($lat) && is_numeric($lng)) {


            $sqlQuery = new SQLQuery();
            $sqlQuery->setFrom('Store');
            $sqlQuery->selectField('( 3959 * acos( cos( radians('.$lat.') ) * cos( radians( lat ) ) * cos( radians( lng ) - radians('.$lng.') ) + sin( radians('.$lat.') ) * sin( radians( lat ) ) ) )','distance');
            //$sqlQuery->selectField('concat(Title, " ", Name)','storename');  //valid concat statement, but SS doesn't like it!
            $sqlQuery->addHaving('distance < 25');
            $sqlQuery->setOrderBy('distance');
            $sqlQuery->setLimit(20);
            $result = $sqlQuery->execute();
            $returnedRecords = new ArrayList();
            foreach($result as $row) {
                $row['Name'] = $row['Title']. ' ' . $row['Name'];
                unset($row['Title']);

                $Address = '';
                $Address.= $row['Address1'] ? $row['Address1'] .', ' : '';
                $Address.= $row['Address2'] ? $row['Address2'] .', ' : '';
                $Address.= $row['Address3'] ? $row['Address3'].', ' : '';
                $Address.= $row['PostCode'] ? $row['PostCode'] : '';
                unset($row['Address1']);
                unset($row['Address2']);
                unset($row['Address3']);

                //insert address line at offset 5 in associative array
                $offset = 5;
                $newArray = array_slice($row, 0, $offset, true) +
                array('Address' => "$Address") +
                array_slice($row, $offset, NULL, true);


                $returnedRecords->push(new ArrayData($newArray));
            }



            return array(
                'Stores'			=> $returnedRecords,
            );
        }

        return null;

    }

}


class StoreAdmin extends ModelAdmin {
    public static $managed_models = array(
        'Store'
    );


    static $url_segment = 'store'; // will be linked as /admin/store
    static $menu_title = 'Store Locations';

}