Initial commit: Homelab API

internal/middleware/auth.go

@@ -0,0 +1,81 @@
+package middleware
+
+import (
+	"context"
+	"net/http"
+	"strings"
+
+	"github.com/golang-jwt/jwt/v5"
+)
+
+type contextKey string
+
+const UserIDKey contextKey = "user_id"
+
+type AuthMiddleware struct {
+	jwtSecret string
+}
+
+func NewAuthMiddleware(jwtSecret string) *AuthMiddleware {
+	return &AuthMiddleware{jwtSecret: jwtSecret}
+}
+
+func (m *AuthMiddleware) Authenticate(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		authHeader := r.Header.Get("Authorization")
+		if authHeader == "" {
+			http.Error(w, `{"error":"missing authorization header"}`, http.StatusUnauthorized)
+			return
+		}
+
+		parts := strings.Split(authHeader, " ")
+		if len(parts) != 2 || parts[0] != "Bearer" {
+			http.Error(w, `{"error":"invalid authorization header"}`, http.StatusUnauthorized)
+			return
+		}
+
+		tokenString := parts[1]
+
+		token, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
+			if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
+				return nil, jwt.ErrSignatureInvalid
+			}
+			return []byte(m.jwtSecret), nil
+		})
+
+		if err != nil || !token.Valid {
+			http.Error(w, `{"error":"invalid token"}`, http.StatusUnauthorized)
+			return
+		}
+
+		claims, ok := token.Claims.(jwt.MapClaims)
+		if !ok {
+			http.Error(w, `{"error":"invalid token claims"}`, http.StatusUnauthorized)
+			return
+		}
+
+		// Check token type
+		tokenType, _ := claims["type"].(string)
+		if tokenType != "access" {
+			http.Error(w, `{"error":"invalid token type"}`, http.StatusUnauthorized)
+			return
+		}
+
+		userID, ok := claims["user_id"].(float64)
+		if !ok {
+			http.Error(w, `{"error":"invalid user id in token"}`, http.StatusUnauthorized)
+			return
+		}
+
+		ctx := context.WithValue(r.Context(), UserIDKey, int64(userID))
+		next.ServeHTTP(w, r.WithContext(ctx))
+	})
+}
+
+func GetUserID(ctx context.Context) int64 {
+	userID, ok := ctx.Value(UserIDKey).(int64)
+	if !ok {
+		return 0
+	}
+	return userID
+}