search_controller.php

<?php
class SearchController extends AppController
{
  var $name = 'Search';
  var $uses = array('Address', 'LiftVendor', 'SubVendor', 'ZipCode');

  /* Search by zip code. */
  function zip($zip_code) {
    set_time_limit(0);      // Because this action could take a while...
    $this->layout = false;  // Used through Ajax, so don't need a layout.
    if (!$zip_code) $this->error_redirect('Must pass a Zip Code', $this->home_path($current_user['User']));

    // The model that we're searching for.
    if (isset($this->passedArgs['model']))
      $model = $this->passedArgs['model'];
    else
      $this->error_redirect('Must pass a model name.', $this->home_path($current_user['User']));

    // Range in miles.
    if (isset($this->passedArgs['range'])) {
      $range = $this->passedArgs['range'];
    } else {
      $range = 5;
    }

    $zip_ranges = $this->ZipCode->find_in_range($zip_code, $range);
    foreach ($zip_ranges as $zip) {
      $record = $this->$model->find('first', array(
                                    'conditions' => array('Address.zip' => $zip['ZipCode']['zip'])));
      if ($record) {
        $record['distance'] = $zip['distance'];
        $records[] = $record;
      }
    }

    if (isset($records)) {
      usort($records, array('SearchController', '_sort_by_distance'));
      $this->set('records', $records);
    }
    $this->set('model', $model);
  }

  private function _sort_by_distance($zip1, $zip2) {
    $first  = $zip1['distance'];
    $second = $zip2['distance'];
    if ($first == $second) return 0;
    return ($first < $second) ? -1 : 1;
  }
}

?>

zip_code.php

<?php
class ZipCode extends AppModel
{
  var $name = 'ZipCode';

  var $validate = array(
    'zip' => array('numeric'),
    'latitude' => array('decimal'),
    'longitude' => array('decimal'),
    'city' => array('notEmpty'),
    'state' => array('notEmpty'),
    'county' => array('notEmpty')
  );

  function find_in_range($zip_code, $range = 5) {
    $zip = $this->find('first', array(
                                'recursive' => -1,
                                'conditions' => array('zip' => $zip_code)));

    // Calculate the latitude/longitude ranges.
    $latitude_range  = $range / 69.172;
    $longitude_range = abs($range / (cos($zip['ZipCode']['longitude']) * 69.172));

    $min_latitude  = $zip['ZipCode']['latitude']  - $latitude_range;
    $max_latitude  = $zip['ZipCode']['latitude']  + $latitude_range;
    $min_longitude = $zip['ZipCode']['longitude'] - $longitude_range;
    $max_longitude = $zip['ZipCode']['longitude'] + $longitude_range;

    $zip_ranges = $this->_in_range($min_latitude,
                                   $max_latitude,
                                   $min_longitude,
                                   $max_longitude);

    // Need to pass by reference, so we can modify the result.
    foreach ($zip_ranges as &$location) {
      $start = array($zip['ZipCode']['latitude'],  $location['ZipCode']['latitude']);
      $end   = array($zip['ZipCode']['longitude'], $location['ZipCode']['longitude']);
      $location['distance'] = $this->_calculate_distance($start, $end);
    }

    return $zip_ranges;
  }

  function _calculate_distance($start = array(), $end = array()) {
    $earth_radius = 3959;
    $div = 57.2958;
    $calc = (sin($start[0]/$div) * (sin($start[1]/$div)) + (cos($start[0]/$div) * (cos($start[1]/$div) * cos(($end[0]/$div) - ($end[1]/$div)))));
    $miles = $earth_radius * atan2(sqrt(1 - (pow($calc, 2))), $calc);
    return $miles;
  }

  private function _in_range($min_lat, $max_lat, $min_long, $max_long) {
    $this->log("Finding zip codes within: ($min_lat, $max_lat) - ($min_long, $max_long)", LOG_DEBUG);
    $zip_ranges = $this->find('all', array(
                       'recursive' => -1,
                       'conditions' => array(
                         'ZipCode.latitude BETWEEN ? AND ?' => array($min_lat, $max_lat),
                         'ZipCode.longitude BETWEEN ? AND ?' => array($min_long, $max_long)
                       ) // conditions
    )); // find()
    return $zip_ranges;
  }
}

?>