geocoder-service.js

/******************
 * Code originally written by Ben Jacobs (benmj)
 * Modified by Weston Siegenthaler (Wsiengenthaler) and Nicholas Bering (Balrog30)
 * Of GitHub Community.
 ******************/

/*global angular: true, google: true, _ : true */

'use strict';

angular.module('geocoder', ['uiGmapgoogle-maps']).factory('geocoderPromise', ['$q', '$timeout', 'uiGmapGoogleMapApi', function ($q, $timeout, GoogleMapApi) {
    var deferredService = $q.defer();
    var locations = {};

    var queue = [];

    // Amount of time (in milliseconds) to pause between each trip to the
    // Geocoding API, which places limits on frequency.
    var queryPause = 250;

    /**
     * executeNext() - execute the next function in the queue. 
     *                  If a result is returned, fulfill the promise.
     *                  If we get an error, reject the promise (with message).
     *                  If we receive OVER_QUERY_LIMIT, increase interval and try again.
     */
    var executeNext = function () {
        var task = queue[0],
          geocoder = new google.maps.Geocoder();

        geocoder.geocode({ address: task.address }, function (result, status) {
            if (status === google.maps.GeocoderStatus.OK) {
                queue.shift();

                locations[task.address] = result;

                task.d.resolve(result);

                if (queue.length) {
                    $timeout(executeNext, queryPause);
                }
            } else if (status === google.maps.GeocoderStatus.ZERO_RESULTS) {
                queue.shift();
                task.d.reject({
                    type: 'zero',
                    message: 'Zero results for geocoding address ' + task.address
                });
            } else if (status === google.maps.GeocoderStatus.OVER_QUERY_LIMIT) {
                queryPause += 250;
                $timeout(executeNext, queryPause);
            } else if (status === google.maps.GeocoderStatus.REQUEST_DENIED) {
                queue.shift();
                task.d.reject({
                    type: 'denied',
                    message: 'Request denied for geocoding address ' + task.address
                });
            } else if (status === google.maps.GeocoderStatus.INVALID_REQUEST) {
                queue.shift();
                task.d.reject({
                    type: 'invalid',
                    message: 'Invalid request for geocoding address ' + task.address
                });
            }
        });
    };

    GoogleMapApi.then(function () {
        deferredService.resolve({
            geocode: function (address) {
                var d = $q.defer();

                if (_.has(locations, address)) {
                    $timeout(function () {
                        d.resolve(locations[address]);
                    });
                } else {
                    queue.push({
                        address: address,
                        d: d
                    });

                    if (queue.length === 1) {
                        executeNext();
                    }
                }

                return d.promise;
            }
        });
    });
    return deferredService.promise;
}]);