From 9f0b0d702e448ae5344e7f1f48f0aa2ad058c121 Mon Sep 17 00:00:00 2001
From: jbergner <jbergner@send.nrw>
Date: Sun, 15 Jun 2025 11:53:34 +0200
Subject: [PATCH] single-mode

---
 go.mod  | 10 +++++++
 go.sum  |  6 ++++
 main.go | 93 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 109 insertions(+)
 create mode 100644 go.mod
 create mode 100644 go.sum
 create mode 100644 main.go

diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..6bcc6a3
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,10 @@
+module git.send.nrw/sendnrw/flod-pod
+
+go 1.24.3
+
+require github.com/redis/go-redis/v9 v9.10.0
+
+require (
+	github.com/cespare/xxhash/v2 v2.3.0 // indirect
+	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
+)
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..0d570ba
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,6 @@
+github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
+github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
+github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f h1:lO4WD4F/rVNCu3HqELle0jiPLLBs70cWOduZpkS1E78=
+github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f/go.mod h1:cuUVRXasLTGF7a8hSLbxyZXjz+1KgoB3wDUb6vlszIc=
+github.com/redis/go-redis/v9 v9.10.0 h1:FxwK3eV8p/CQa0Ch276C7u2d0eNC9kCmAYQ7mCXCzVs=
+github.com/redis/go-redis/v9 v9.10.0/go.mod h1:huWgSWd8mW6+m0VPhJjSSQ+d6Nh1VICQ6Q5lHuCH/Iw=
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..3e467f2
--- /dev/null
+++ b/main.go
@@ -0,0 +1,93 @@
+package main
+
+import (
+	"context"
+	"log"
+	"net"
+	"net/http"
+	"strings"
+
+	"github.com/redis/go-redis/v9"
+)
+
+var (
+	ctx         = context.Background()
+	redisClient *redis.Client
+	hashName    = "bl:sendnrw"
+)
+
+func main() {
+	// Redis Client initialisieren
+	redisClient = redis.NewClient(&redis.Options{
+		Addr:     "10.10.5.249:6379", // ggf. anpassen
+		Password: "",                 // falls Passwort benötigt wird
+		DB:       0,                  // Standard DB
+	})
+
+	// Testverbindung
+	if err := redisClient.Ping(ctx).Err(); err != nil {
+		log.Fatalf("Keine Verbindung zu Redis: %v", err)
+	}
+
+	http.HandleFunc("/", logIPHandler)
+
+	log.Println("Server startet auf :8082")
+	if err := http.ListenAndServe(":8082", nil); err != nil {
+		log.Fatal("ListenAndServe: ", err)
+	}
+}
+
+func logIPHandler(w http.ResponseWriter, r *http.Request) {
+	ip := getClientIP(r)
+	if ip == "" {
+		http.Error(w, "Ungültige IP", http.StatusBadRequest)
+		return
+	}
+
+	ipKey := ip + "/32"
+
+	// IP in Redis Hash speichern
+	err := redisClient.HSet(ctx, hashName, ipKey, 1).Err()
+	if err != nil {
+		log.Printf("Fehler beim Schreiben in Redis: %v", err)
+		http.Error(w, "Interner Fehler", http.StatusInternalServerError)
+		return
+	}
+
+	log.Printf("IP %s in Redis gespeichert", ipKey)
+
+	w.WriteHeader(http.StatusOK)
+	w.Write([]byte("IP erfasst: " + ipKey + "\n"))
+}
+
+func getClientIP(r *http.Request) string {
+	// X-Forwarded-For prüfen
+	xff := r.Header.Get("X-Forwarded-For")
+	if xff != "" {
+		parts := strings.Split(xff, ",")
+		ip := strings.TrimSpace(parts[0])
+		if isValidIP(ip) {
+			return ip
+		}
+	}
+
+	// X-Real-IP prüfen
+	xrip := r.Header.Get("X-Real-Ip")
+	if xrip != "" && isValidIP(xrip) {
+		return xrip
+	}
+
+	// RemoteAddr als Fallback
+	host, _, err := net.SplitHostPort(r.RemoteAddr)
+	if err != nil {
+		return ""
+	}
+	if isValidIP(host) {
+		return host
+	}
+	return ""
+}
+
+func isValidIP(ip string) bool {
+	return net.ParseIP(ip) != nil
+}