crossover

backend-go/internal/middleware/auth.go

@@ -0,0 +1,98 @@
+package middleware
+
+import (
+	"context"
+	"encoding/json"
+	"log"
+	"net/http"
+	"strings"
+
+	fbauth "github.com/kjannette/koin-ping/backend-go/internal/firebase"
+)
+
+type contextKey string
+
+const (
+	UserIDKey    contextKey = "user_id"
+	UserEmailKey contextKey = "user_email"
+)
+
+type errorResponse struct {
+	Error   string `json:"error"`
+	Message string `json:"message"`
+}
+
+func writeJSON(w http.ResponseWriter, status int, v interface{}) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	json.NewEncoder(w).Encode(v)
+}
+
+func Authenticate(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		authHeader := r.Header.Get("Authorization")
+		if authHeader == "" || !strings.HasPrefix(authHeader, "Bearer ") {
+			log.Println("No Authorization header or invalid format")
+			writeJSON(w, http.StatusUnauthorized, errorResponse{
+				Error:   "UNAUTHORIZED",
+				Message: "No authentication token provided",
+			})
+			return
+		}
+
+		token := strings.TrimPrefix(authHeader, "Bearer ")
+		if token == "" {
+			log.Println("Empty token")
+			writeJSON(w, http.StatusUnauthorized, errorResponse{
+				Error:   "UNAUTHORIZED",
+				Message: "Invalid token format",
+			})
+			return
+		}
+
+		log.Println("Verifying Firebase token...")
+		decoded, err := fbauth.Auth().VerifyIDToken(r.Context(), token)
+		if err != nil {
+			log.Printf("Token verification failed: %v", err)
+
+			errMsg := err.Error()
+			if strings.Contains(errMsg, "expired") {
+				writeJSON(w, http.StatusUnauthorized, errorResponse{
+					Error:   "TOKEN_EXPIRED",
+					Message: "Authentication token has expired",
+				})
+				return
+			}
+
+			writeJSON(w, http.StatusUnauthorized, errorResponse{
+				Error:   "UNAUTHORIZED",
+				Message: "Failed to verify authentication token",
+			})
+			return
+		}
+
+		userID := decoded.UID
+		email, _ := decoded.Claims["email"].(string)
+
+		log.Printf("Token verified! User ID: %s, Email: %s", userID, email)
+
+		ctx := context.WithValue(r.Context(), UserIDKey, userID)
+		ctx = context.WithValue(ctx, UserEmailKey, email)
+
+		next.ServeHTTP(w, r.WithContext(ctx))
+	})
+}
+
+func GetUserID(ctx context.Context) string {
+	if v, ok := ctx.Value(UserIDKey).(string); ok {
+		return v
+	}
+	return ""
+}
+
+func GetUserEmail(ctx context.Context) string {
+	if v, ok := ctx.Value(UserEmailKey).(string); ok {
+		return v
+	}
+	return ""
+}