Initial commit

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/internal/handler/middleware.go

@@ -0,0 +1,52 @@
+package handler
+
+import (
+	"log"
+	"net/http"
+	"time"
+)
+
+// Chain wendet Middlewares in der angegebenen Reihenfolge an.
+func Chain(h http.Handler, middlewares ...func(http.Handler) http.Handler) http.Handler {
+	for i := len(middlewares) - 1; i >= 0; i-- {
+		h = middlewares[i](h)
+	}
+	return h
+}
+
+// CORS erlaubt Cross-Origin-Requests vom Vite Dev-Server.
+func CORS(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Access-Control-Allow-Origin", "http://*")
+		w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS")
+		w.Header().Set("Access-Control-Allow-Headers", "Content-Type")
+
+		if r.Method == http.MethodOptions {
+			w.WriteHeader(http.StatusNoContent)
+			return
+		}
+		next.ServeHTTP(w, r)
+	})
+}
+
+// RequestLogger loggt eingehende Requests mit Dauer.
+func RequestLogger(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		start := time.Now()
+		next.ServeHTTP(w, r)
+		log.Printf("%s %s %s", r.Method, r.URL.Path, time.Since(start))
+	})
+}
+
+// Recoverer fängt Panics in Handlern ab und gibt 500 zurück.
+func Recoverer(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		defer func() {
+			if err := recover(); err != nil {
+				log.Printf("PANIC: %v", err)
+				writeError(w, http.StatusInternalServerError, "Interner Serverfehler")
+			}
+		}()
+		next.ServeHTTP(w, r)
+	})
+}