From 513b59fa8875d77c86f122af4bb0cc547eb98c8f Mon Sep 17 00:00:00 2001
From: Notealot <714804968@qq.com>
Date: Wed, 27 Oct 2021 00:19:06 +0800
Subject: [PATCH] rationalize return logic in validateHeader()

---
 gin.go | 29 ++++++++++++++---------------
 1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/gin.go b/gin.go
index bee42dee..73f71a3c 100644
--- a/gin.go
+++ b/gin.go
@@ -416,24 +416,23 @@ func (engine *Engine) isTrustedProxy(ip net.IP) bool {
 }
 
 func (engine *Engine) validateHeader(header string) (clientIP string, valid bool) {
-	if header == "" {
-		return "", false
-	}
-	items := strings.Split(header, ",")
-	for i := len(items) - 1; i >= 0; i-- {
-		ipStr := strings.TrimSpace(items[i])
-		ip := net.ParseIP(ipStr)
-		if ip == nil {
-			return "", false
-		}
+	if header != "" {
+		items := strings.Split(header, ",")
+		for i := len(items) - 1; i >= 0; i-- {
+			ipStr := strings.TrimSpace(items[i])
+			ip := net.ParseIP(ipStr)
+			if ip == nil {
+				return "", false
+			}
 
-		// X-Forwarded-For is appended by proxy
-		// Check IPs in reverse order and stop when find untrusted proxy
-		if (i == 0) || (!engine.isTrustedProxy(ip)) {
-			return ipStr, true
+			// X-Forwarded-For is appended by proxy
+			// Check IPs in reverse order and stop when find untrusted proxy
+			if (i == 0) || (!engine.isTrustedProxy(ip)) {
+				return ipStr, true
+			}
 		}
 	}
-	return
+	return "", false
 }
 
 // parseTrustedProxies parse Engine.trustedProxies to Engine.trustedCIDRs