Golang : Find location by IP address and display with Google Map
This tutorial is a follow up for the previous tutorial on how to detect a user location with HTML5 Geolocation. However, this time we will learn how to get a user longitude and latitude from a user's IP address with the GeoLite2 free database and display the location visually with Google Map.
First, let's get the required ingredients by :
go get github.com/oschwald/geoip2-golang
go get github.com/gorilla/mux
and
wget http://geolite.maxmind.com/download/geoip/database/GeoLite2-City.mmdb.gz
gunzip GeoLite2-City.mmdb.gz
Next, we define our template plus JQuery to handle user input and canvas to display Google map.
Filename :
asklocation.html
<html>
<head>
<title>IP to location Golang example</title>
<meta name="viewport" content="initial-scale=1.0, user-scalable=no">
<meta charset="utf-8">
<style>
html, body, #map-canvas {
height: 80%;
margin: 0px;
padding: 0px
}
</style>
<script src="https://maps.googleapis.com/maps/api/js?v=3.exp&signed_in=true"></script>
<script src="//code.jquery.com/jquery-1.11.3.min.js"></script>
</head>
<body>
<h1>IP to Location Golang example</h1>
<div>
<input type="text" placeholder="0.0.0.0" id="ajax_btn" value="">
<span>
<button id="ajax_btn_search" type="button">Search</button>
</span>
</div>
<script>
$(document).ready(function () {
$('#ajax_btn_search').click(function () {
ipAddress = $('#ajax_btn').val()
$.ajax({
url: 'returncoord',
type: 'post',
dataType: 'html',
data : { ajax_post_data: ipAddress},
success : function(data) {
$('#result').html(data);
//get the Lat and Long as JSON
var json = JSON.parse(data);
showMap(json["Lat"], json["Long"], ipAddress);
},
});
});
});
var map;
function showMap(latitude,longitude,ipaddress) {
var pos = new google.maps.LatLng(latitude,longitude);
var mapOptions = {
zoom: 5,
center: pos,
mapTypeId: google.maps.MapTypeId.ROADMAP,
content : 'Location found by IP Address'
};
var mapDiv = document.getElementById("map-canvas");
map = new google.maps.Map(mapDiv, mapOptions);
var title = ipaddress + " location";
addMarker(map, pos, title, "");
}
function addMarker(map, latlong, title, content) {
var markerOptions = {
position: latlong,
map: map,
title: title,
clickable: true
};
var marker = new google.maps.Marker(markerOptions);
}
</script>
<div id='result'></div>
<br>
<br>
<div id="map-canvas"></div>
</body>
</html>
Filename :
asklocation.go
package main
import (
"fmt"
"github.com/gorilla/mux"
"github.com/oschwald/geoip2-golang"
"html/template"
"net"
"net/http"
)
func home(w http.ResponseWriter, r *http.Request) {
var templates = template.Must(template.New("locateip").ParseFiles("asklocation.html"))
err := templates.ExecuteTemplate(w, "asklocation.html", nil)
if err != nil {
panic(err)
}
}
func returnLatLong(w http.ResponseWriter, r *http.Request) {
// not recommended to open the file each time per request
// we put it here for tutorial sake.
db, err := geoip2.Open("GeoLite2-City.mmdb")
if err != nil {
fmt.Println(err)
}
defer db.Close()
if r.Method == "POST" {
ipAddress := r.FormValue("ajax_post_data")
// If you are using strings that may be invalid, check that IP is not nil
// and a valid IP address -- see https://www.socketloop.com/tutorials/golang-validate-ip-address
if ipAddress != "" {
ip := net.ParseIP(ipAddress)
record, err := db.City(ip)
if err != nil {
fmt.Println(err)
}
fmt.Printf("Country name in English: %v\n", record.Country.Names["en"])
fmt.Printf("Coordinates: Lat(%v), Long(%v)\n", record.Location.Latitude, record.Location.Longitude)
w.Write([]byte(fmt.Sprintf("{\"Country\":\"%v\",\"Lat\": \"%v\",\"Long\":\"%v\"}", record.Country.Names["en"],record.Location.Latitude, record.Location.Longitude)))
}
}
}
func main() {
mux := mux.NewRouter()
mux.HandleFunc("/", home)
mux.HandleFunc("/returncoord", returnLatLong)
http.ListenAndServe(":8080", mux)
}
Run the asklocation.go file, point your browser to
Put in an IP address and click on the search button.
Hope this helps and happy coding!
NOTE : The GeoLite2 free database at http://dev.maxmind.com/geoip/geoip2/geolite2/ is by MaxMind
References :
https://godoc.org/github.com/oschwald/geoip2-golang
https://github.com/oschwald/geoip2-golang
https://www.socketloop.com/tutorials/javascript-read-parse-json-data-from-http-response
See also : Golang : Detect user location with HTML5 geo-location
By Adam Ng
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