added real_ip and cloudflare_real_ip middlewares, fixed that some middlewares does not work properly

internal/net/http/header_utils.go

@@ -0,0 +1,42 @@
+package http
+
+import (
+	"net/http"
+	"slices"
+)
+
+func RemoveHop(h http.Header) {
+	reqUpType := UpgradeType(h)
+	RemoveHopByHopHeaders(h)
+
+	if reqUpType != "" {
+		h.Set("Connection", "Upgrade")
+		h.Set("Upgrade", reqUpType)
+	} else {
+		h.Del("Connection")
+	}
+}
+
+func CopyHeader(dst, src http.Header) {
+	for k, vv := range src {
+		for _, v := range vv {
+			dst.Add(k, v)
+		}
+	}
+}
+
+func FilterHeaders(h http.Header, allowed []string) {
+	if allowed == nil {
+		return
+	}
+
+	for i := range allowed {
+		allowed[i] = http.CanonicalHeaderKey(allowed[i])
+	}
+
+	for key := range h {
+		if !slices.Contains(allowed, key) {
+			h.Del(key)
+		}
+	}
+}