feat(ipinfo): support GeoIP (#26)

Co-authored-by: E99p1ant <[email protected]>

internal/ipinfo/geoip/geo.go

@@ -0,0 +1,67 @@
+package geoip
+
+import (
+	"fmt"
+	"net"
+	"os"
+	"sync"
+	"time"
+
+	"github.com/oschwald/geoip2-golang"
+	log "unknwon.dev/clog/v2"
+)
+
+type Database struct {
+	geo *geoip2.Reader
+}
+
+var geo *geoip2.Reader
+var once sync.Once
+
+// Area returns IpArea according to ip
+func (db *Database) Area(ip string) string {
+	defer func() {
+		_ = recover()
+	}()
+	record, err := db.geo.City(net.ParseIP(ip))
+	if err != nil {
+		return ""
+	}
+
+	country := record.Country.Names["en"]
+	city := record.City.Names["en"]
+	if city == "" {
+		city = record.Location.TimeZone
+	}
+	return fmt.Sprintf("%s %s", country, city)
+}
+
+func checkUpdate(licenseKey string) {
+	info, err := os.Stat("GeoLite2-City.mmdb")
+	if err != nil {
+		if os.IsNotExist(err) {
+			err := download(licenseKey)
+			if err != nil {
+				log.Warn("Download GeoLite2-City.mmdb failed, caused by:%v, recommend to download it by yourself otherwise the `IpArea` will be null", err)
+			}
+		}
+	} else if -time.Until(info.ModTime()) > 7*24*time.Hour {
+		log.Info("Updating GeoLite2-City.mmdb...")
+		err := download(licenseKey)
+		if err != nil {
+			log.Warn("Update GeoLite2-City.mmdb failed, please download GeoLite2-City.mmdb by yourself")
+		}
+	}
+}
+
+func New(licenseKey string) *Database {
+	once.Do(func() {
+		var err error
+		checkUpdate(licenseKey)
+		geo, err = geoip2.Open("GeoLite2-City.mmdb")
+		if err != nil {
+			log.Error("Load GeoLite2-City.mmdb failed, `IpArea` will be null")
+		}
+	})
+	return &Database{geo: geo}
+}