Initial Commit

http.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"net"
+	"net/http"
+	"strings"
+)
+
+// realIP is a middleware that extracts the real IP from the headers of
+// an HTTP requests and modifies the request for the next handler.
+func realIP(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if ip := realIPFromHeaders(r); ip != "" {
+			r.RemoteAddr = net.JoinHostPort(ip, "0")
+		}
+		next.ServeHTTP(w, r)
+	})
+}
+
+// realIPFromHeaders extracts the real IP from the headers of an HTTP request
+func realIPFromHeaders(r *http.Request) string {
+	xff := r.Header.Get("X-Forwarded-For")
+	if xff != "" {
+		parts := strings.Split(xff, ",")
+		if len(parts) > 0 {
+			ip := strings.TrimSpace(parts[0])
+			if ip != "" {
+				return ip
+			}
+		}
+	}
+	xrip := strings.TrimSpace(r.Header.Get("X-Real-IP"))
+	if xrip != "" {
+		return xrip
+	}
+	return ""
+}