add clientIP for handler recorder object

internal/net/http/http.go

@@ -0,0 +1,26 @@
+package http
+
+import (
+	"net"
+	"net/http"
+	"strings"
+)
+
+func GetClientIP(req *http.Request) net.IP {
+	if req == nil {
+		return nil
+	}
+	// cloudflare CDN
+	sip := req.Header.Get("CF-Connecting-IP")
+	if sip == "" {
+		ss := strings.Split(req.Header.Get("X-Forwarded-For"), ",")
+		if len(ss) > 0 && ss[0] != "" {
+			sip = ss[0]
+		}
+	}
+	if sip == "" {
+		sip = req.Header.Get("X-Real-Ip")
+	}
+
+	return net.ParseIP(sip)
+}