feat(ipinfo): support GeoIP (#26)

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

internal/ipinfo/geoip/download.go

@@ -0,0 +1,86 @@
+package geoip
+
+import (
+	"archive/tar"
+	"bytes"
+	"compress/gzip"
+	"crypto/tls"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"strings"
+	"time"
+
+	log "unknwon.dev/clog/v2"
+)
+
+const (
+	Url = "https://download.maxmind.com/app/geoip_download?edition_id=GeoLite2-City&license_key=%s&suffix=tar.gz"
+)
+
+func get(url string) (b []byte, err error) {
+	client := http.Client{
+		Timeout: 90 * time.Second,
+		Transport: &http.Transport{
+			TLSClientConfig: &tls.Config{InsecureSkipVerify: true}, // disable verify
+		}}
+	request, _ := http.NewRequest(http.MethodGet, url, nil)
+	request.Header.Add("User-Agent", "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.77 Safari/537.36")
+
+	resp, err := client.Do(request)
+	if err != nil {
+		return
+	}
+	defer resp.Body.Close()
+
+	return io.ReadAll(resp.Body)
+}
+
+func extractTarGz(gzipStream io.Reader) error {
+	uncompressedStream, err := gzip.NewReader(gzipStream)
+	if err != nil {
+		return err
+	}
+
+	tarReader := tar.NewReader(uncompressedStream)
+
+	for {
+		header, err := tarReader.Next()
+
+		if err == io.EOF {
+			break
+		}
+
+		if err != nil {
+			return err
+		}
+
+		switch header.Typeflag {
+		case tar.TypeReg:
+			log.Trace(header.Name)
+			if !strings.HasSuffix(header.Name, "GeoLite2-City.mmdb") {
+				continue
+			}
+			outFile, err := os.Create("GeoLite2-City.mmdb")
+			if err != nil {
+				return err
+			}
+			defer outFile.Close()
+			if _, err := io.Copy(outFile, tarReader); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func download(licenseKey string) (err error) {
+	var GeoLite2TarGz []byte
+	log.Info("Downloading GeoLite2-City.mmdb...")
+	if GeoLite2TarGz, err = get(fmt.Sprintf(Url, licenseKey)); err != nil {
+		return err
+	}
+
+	return extractTarGz(bytes.NewReader(GeoLite2TarGz))
+}