Extract iputil package

iputil/db/db.go

@@ -0,0 +1,89 @@
+package db
+
+import (
+	"net"
+
+	geoip2 "github.com/oschwald/geoip2-golang"
+)
+
+type Database interface {
+	Country(net.IP) (Country, error)
+	City(net.IP) (string, error)
+}
+
+type Country struct {
+	Name string
+	ISO  string
+}
+
+type geoip struct {
+	country *geoip2.Reader
+	city    *geoip2.Reader
+}
+
+type empty struct{}
+
+func (d *empty) Country(ip net.IP) (Country, error) { return Country{}, nil }
+func (d *empty) City(ip net.IP) (string, error)     { return "", nil }
+
+func Empty() Database { return &empty{} }
+
+func Open(countryDB, cityDB string) (Database, error) {
+	var (
+		country *geoip2.Reader
+		city    *geoip2.Reader
+	)
+	if countryDB != "" {
+		r, err := geoip2.Open(countryDB)
+		if err != nil {
+			return nil, err
+		}
+		country = r
+	}
+	if cityDB != "" {
+		r, err := geoip2.Open(cityDB)
+		if err != nil {
+			return nil, err
+		}
+		city = r
+	}
+	return &geoip{country: country, city: city}, nil
+}
+
+func (g *geoip) Country(ip net.IP) (Country, error) {
+	country := Country{}
+	if g.country == nil {
+		return country, nil
+	}
+	record, err := g.country.Country(ip)
+	if err != nil {
+		return country, err
+	}
+	if c, exists := record.Country.Names["en"]; exists {
+		country.Name = c
+	}
+	if c, exists := record.RegisteredCountry.Names["en"]; exists && country.Name == "" {
+		country.Name = c
+	}
+	if record.Country.IsoCode != "" {
+		country.ISO = record.Country.IsoCode
+	}
+	if record.RegisteredCountry.IsoCode != "" && country.ISO == "" {
+		country.ISO = record.RegisteredCountry.IsoCode
+	}
+	return country, nil
+}
+
+func (g *geoip) City(ip net.IP) (string, error) {
+	if g.city == nil {
+		return "", nil
+	}
+	record, err := g.city.City(ip)
+	if err != nil {
+		return "", err
+	}
+	if city, exists := record.City.Names["en"]; exists {
+		return city, nil
+	}
+	return "", nil
+}