improve the performance of IP validation functionality

ctx.go

@@ -662,10 +662,38 @@ func (c *Ctx) IP() string {
 // extractValidIPs will return a slice of strings that represent valid IP addresses
 // in the input string. The order is maintained. The separator is a comma
 func extractValidIPs(input string) (validIPs []string) {
-	unvalidatedIps := strings.Split(input, ",")
-	for _, ip := range unvalidatedIps {
-		if parsedIp := net.ParseIP(strings.TrimSpace(ip)); parsedIp != nil {
-			validIPs = append(validIPs, parsedIp.String())
+
+	// try to gather IPs in the input with minimal allocations to improve performance
+	ips := make([]string, bytes.Count([]byte(input), []byte(","))+1)
+	var commaPos, i, validCount int
+	for {
+		commaPos = bytes.IndexByte([]byte(input), ',')
+		if commaPos != -1 {
+			if net.ParseIP(utils.Trim(input[:commaPos], ' ')) != nil {
+				ips[i] = utils.Trim(input[:commaPos], ' ')
+				validCount++
+			}
+			input, i = input[commaPos+1:], i+1
+		} else {
+			if net.ParseIP(utils.Trim(input, ' ')) != nil {
+				ips[i] = utils.Trim(input, ' ')
+				validCount++
+			}
+			break
+		}
+	}
+
+	// filter out any bad IPs that we found
+	if len(ips) == validCount {
+		validIPs = ips
+	} else {
+		validIPs = make([]string, validCount)
+		var validIndex int
+		for n := range ips {
+			if ips[n] != "" {
+				validIPs[validIndex] = ips[n]
+				validIndex++
+			}
 		}
 	}
 	return

ctx_test.go

@@ -1215,6 +1215,34 @@ func Benchmark_Ctx_IPs(b *testing.B) {
 	utils.AssertEqual(b, []string{"127.0.0.1", "127.0.0.1", "127.0.0.1"}, res)
 }
 
+func Benchmark_Ctx_IP_With_ProxyHeader(b *testing.B) {
+	app := New(Config{ProxyHeader: HeaderXForwardedFor})
+	c := app.AcquireCtx(&fasthttp.RequestCtx{})
+	defer app.ReleaseCtx(c)
+	c.Request().Header.Set(HeaderXForwardedFor, "127.0.0.1")
+	var res string
+	b.ReportAllocs()
+	b.ResetTimer()
+	for n := 0; n < b.N; n++ {
+		res = c.IP()
+	}
+	utils.AssertEqual(b, "127.0.0.1", res)
+}
+
+func Benchmark_Ctx_IP(b *testing.B) {
+	app := New()
+	c := app.AcquireCtx(&fasthttp.RequestCtx{})
+	defer app.ReleaseCtx(c)
+	c.Request()
+	var res string
+	b.ReportAllocs()
+	b.ResetTimer()
+	for n := 0; n < b.N; n++ {
+		res = c.IP()
+	}
+	utils.AssertEqual(b, "0.0.0.0", res)
+}
+
 // go test -run Test_Ctx_Is
 func Test_Ctx_Is(t *testing.T) {
 	t.Parallel()