Google API for location, based on user IP address

Question

I am looking for a way to get the user's current location (city) based on is IP address using the Google Maps APIs.

Something similar to http://freegeoip.net/json but only using the Google Maps APIs. Is this possible?

Answer 1

Google already appends location data to all requests coming into GAE (see Request Header documentation for go, java, php and python). You should be interested X-AppEngine-Country, X-AppEngine-Region, X-AppEngine-City and X-AppEngine-CityLatLong headers.

An example looks like this:

X-AppEngine-Country:US
X-AppEngine-Region:ca
X-AppEngine-City:norwalk
X-AppEngine-CityLatLong:33.902237,-118.081733

Answer 2

It looks like Google actively frowns on using IP-to-location mapping:

https://developers.google.com/maps/articles/geolocation?hl=en

That article encourages using the W3C geolocation API. I was a little skeptical, but it looks like almost every major browser already supports the geolocation API:

http://caniuse.com/geolocation

Answer 3

Here's a script that will use the Google API to acquire the users postal code and populate an input field.

function postalCodeLookup(input) {
    var head= document.getElementsByTagName('head')[0],
        script= document.createElement('script');
    script.src= '//maps.googleapis.com/maps/api/js?sensor=false';
    head.appendChild(script);
    script.onload = function() {
        if (navigator.geolocation) {
            var a = input,
                fallback = setTimeout(function () {
                    fail('10 seconds expired');
                }, 10000);

            navigator.geolocation.getCurrentPosition(function (pos) {
                clearTimeout(fallback);
                var point = new google.maps.LatLng(pos.coords.latitude, pos.coords.longitude);
                new google.maps.Geocoder().geocode({'latLng': point}, function (res, status) {
                    if (status == google.maps.GeocoderStatus.OK && typeof res[0] !== 'undefined') {
                        var zip = res[0].formatted_address.match(/,\s\w{2}\s(\d{5})/);
                        if (zip) {
                            a.value = zip[1];
                        } else fail('Unable to look-up postal code');
                    } else {
                        fail('Unable to look-up geolocation');
                    }
                });
            }, function (err) {
                fail(err.message);
            });
        } else {
            alert('Unable to find your location.');
        }
        function fail(err) {
            console.log('err', err);
            a.value('Try Again.');
        }
    };
}

You can adjust accordingly to acquire different information. For more info, check out the Google Maps API documentation.