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freegeoip web server using httpmux
package main
import (
"bytes"
"encoding/csv"
"encoding/json"
"encoding/xml"
"fmt"
"log"
"math/rand"
"net"
"net/http"
"os"
"strconv"
"time"
"github.com/fiorix/freegeoip"
"golang.org/x/net/context"
"github.com/go-web/httplog"
"github.com/go-web/httpmux"
)
func init() {
rand.Seed(time.Now().UnixNano())
}
var maxmindDB = "http://geolite.maxmind.com/download/geoip/database/GeoLite2-City.mmdb.gz"
func main() {
db, err := freegeoip.OpenURL(maxmindDB, 24*time.Hour, time.Hour)
if err != nil {
log.Fatal(err)
}
f := &handler{db: db}
mux := httpmux.New()
l := log.New(os.Stderr, "", 0)
mux.Use(httplog.ApacheCombinedFormat(l))
mux.Use(f.QueryIP)
mux.GET("/json/*host", f.JSON)
mux.GET("/xml/*host", f.XML)
mux.GET("/csv/*host", f.CSV)
err = http.ListenAndServe(":8080", mux)
if err != nil {
log.Fatal(err)
}
}
type handler struct {
db *freegeoip.DB
}
func (f *handler) QueryIP(next http.HandlerFunc) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
host := httpmux.Params(r).ByName("host")
switch len(host) {
case 1:
host, _, _ = net.SplitHostPort(r.RemoteAddr)
if host == "" {
host = r.RemoteAddr
}
default:
host = host[1:]
}
ips, err := net.LookupIP(host)
if err != nil || len(ips) == 0 {
http.NotFound(w, r)
return
}
q := &lookupQuery{}
ip := ips[rand.Intn(len(ips))]
err = f.db.Lookup(ip, q)
if err != nil {
http.Error(w, "Try again later.", http.StatusServiceUnavailable)
return
}
resp := q.Record(ip, r.Header.Get("Accept-Language"))
ctx := context.WithValue(httpmux.Context(r), "resp", resp)
httpmux.SetContext(ctx, r)
next(w, r)
}
}
func (f *handler) JSON(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "application/json")
resp := httpmux.Context(r).Value("resp")
json.NewEncoder(w).Encode(resp)
}
func (f *handler) XML(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "application/xml")
resp := httpmux.Context(r).Value("resp")
x := xml.NewEncoder(w)
x.Indent("", "\t")
x.Encode(resp)
w.Write([]byte{'\n'})
}
func (f *handler) CSV(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "text/csv")
resp := httpmux.Context(r).Value("resp")
fmt.Fprint(w, resp)
}
type lookupQuery struct {
Country struct {
ISOCode string `maxminddb:"iso_code"`
Names map[string]string `maxminddb:"names"`
} `maxminddb:"country"`
Region []struct {
ISOCode string `maxminddb:"iso_code"`
Names map[string]string `maxminddb:"names"`
} `maxminddb:"subdivisions"`
City struct {
Names map[string]string `maxminddb:"names"`
} `maxminddb:"city"`
Location struct {
Latitude float64 `maxminddb:"latitude"`
Longitude float64 `maxminddb:"longitude"`
MetroCode uint `maxminddb:"metro_code"`
TimeZone string `maxminddb:"time_zone"`
} `maxminddb:"location"`
Postal struct {
Code string `maxminddb:"code"`
} `maxminddb:"postal"`
}
func (lq *lookupQuery) Record(ip net.IP, lang string) *responseRecord {
// TODO: parse accept-language value from lang.
if lq.Country.Names[lang] == "" {
lang = "en"
}
r := &responseRecord{
IP: ip.String(),
CountryCode: lq.Country.ISOCode,
CountryName: lq.Country.Names[lang],
City: lq.City.Names[lang],
ZipCode: lq.Postal.Code,
TimeZone: lq.Location.TimeZone,
Latitude: lq.Location.Latitude,
Longitude: lq.Location.Longitude,
MetroCode: lq.Location.MetroCode,
}
if len(lq.Region) > 0 {
r.RegionCode = lq.Region[0].ISOCode
r.RegionName = lq.Region[0].Names[lang]
}
return r
}
type responseRecord struct {
XMLName xml.Name `xml:"Response" json:"-"`
IP string `json:"ip"`
CountryCode string `json:"country_code"`
CountryName string `json:"country_name"`
RegionCode string `json:"region_code"`
RegionName string `json:"region_name"`
City string `json:"city"`
ZipCode string `json:"zip_code"`
TimeZone string `json:"time_zone"`
Latitude float64 `json:"latitude"`
Longitude float64 `json:"longitude"`
MetroCode uint `json:"metro_code"`
}
func (rr *responseRecord) String() string {
b := &bytes.Buffer{}
w := csv.NewWriter(b)
w.UseCRLF = true
w.Write([]string{
rr.IP,
rr.CountryCode,
rr.CountryName,
rr.RegionCode,
rr.RegionName,
rr.City,
rr.ZipCode,
rr.TimeZone,
strconv.FormatFloat(rr.Latitude, 'f', 2, 64),
strconv.FormatFloat(rr.Longitude, 'f', 2, 64),
strconv.Itoa(int(rr.MetroCode)),
})
w.Flush()
return b.String()
}
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