refactor: use GetValidatedDTO for vote validation

internal/handlers/auth_handler.go

@@ -64,14 +64,13 @@ func NewAuthHandler(authService AuthServiceInterface, userRepo repositories.User
 // @Failure 500 {object} AuthResponse "Internal server error"
 // @Router /api/auth/login [post]
 func (h *AuthHandler) Login(w http.ResponseWriter, r *http.Request) {
-	req, ok := GetValidatedDTO[dto.LoginRequest](r)
+	request, ok := GetValidatedDTO[dto.LoginRequest](w, r)
 	if !ok {
-		SendErrorResponse(w, "Invalid request", http.StatusBadRequest)
 		return
 	}
 
-	username := security.SanitizeUsername(req.Username)
-	password := strings.TrimSpace(req.Password)
+	username := security.SanitizeUsername(request.Username)
+	password := strings.TrimSpace(request.Password)
 
 	result, err := h.authService.Login(username, password)
 	if !HandleServiceError(w, err, "Authentication failed", http.StatusInternalServerError) {
@@ -94,15 +93,14 @@ func (h *AuthHandler) Login(w http.ResponseWriter, r *http.Request) {
 // @Failure 500 {object} AuthResponse "Internal server error"
 // @Router /api/auth/register [post]
 func (h *AuthHandler) Register(w http.ResponseWriter, r *http.Request) {
-	req, ok := GetValidatedDTO[dto.RegisterRequest](r)
+	request, ok := GetValidatedDTO[dto.RegisterRequest](w, r)
 	if !ok {
-		SendErrorResponse(w, "Invalid request", http.StatusBadRequest)
 		return
 	}
 
-	username := strings.TrimSpace(req.Username)
-	email := strings.TrimSpace(req.Email)
-	password := strings.TrimSpace(req.Password)
+	username := strings.TrimSpace(request.Username)
+	email := strings.TrimSpace(request.Email)
+	password := strings.TrimSpace(request.Password)
 
 	username = security.SanitizeUsername(username)
 
@@ -163,13 +161,12 @@ func (h *AuthHandler) ConfirmEmail(w http.ResponseWriter, r *http.Request) {
 // @Failure 500 {object} AuthResponse
 // @Router /api/auth/resend-verification [post]
 func (h *AuthHandler) ResendVerificationEmail(w http.ResponseWriter, r *http.Request) {
-	req, ok := GetValidatedDTO[dto.ResendVerificationRequest](r)
+	request, ok := GetValidatedDTO[dto.ResendVerificationRequest](w, r)
 	if !ok {
-		SendErrorResponse(w, "Invalid request", http.StatusBadRequest)
 		return
 	}
 
-	email := strings.TrimSpace(req.Email)
+	email := strings.TrimSpace(request.Email)
 
 	if email == "" {
 		SendErrorResponse(w, "Email address is required", http.StatusBadRequest)
@@ -237,13 +234,12 @@ func (h *AuthHandler) Me(w http.ResponseWriter, r *http.Request) {
 // @Failure 400 {object} AuthResponse "Invalid request data"
 // @Router /api/auth/forgot-password [post]
 func (h *AuthHandler) RequestPasswordReset(w http.ResponseWriter, r *http.Request) {
-	req, ok := GetValidatedDTO[dto.ForgotPasswordRequest](r)
+	request, ok := GetValidatedDTO[dto.ForgotPasswordRequest](w, r)
 	if !ok {
-		SendErrorResponse(w, "Invalid request", http.StatusBadRequest)
 		return
 	}
 
-	usernameOrEmail := strings.TrimSpace(req.UsernameOrEmail)
+	usernameOrEmail := strings.TrimSpace(request.UsernameOrEmail)
 
 	if usernameOrEmail == "" {
 		SendErrorResponse(w, "Username or email is required", http.StatusBadRequest)
@@ -267,14 +263,13 @@ func (h *AuthHandler) RequestPasswordReset(w http.ResponseWriter, r *http.Reques
 // @Failure 500 {object} AuthResponse "Internal server error"
 // @Router /api/auth/reset-password [post]
 func (h *AuthHandler) ResetPassword(w http.ResponseWriter, r *http.Request) {
-	req, ok := GetValidatedDTO[dto.ResetPasswordRequest](r)
+	request, ok := GetValidatedDTO[dto.ResetPasswordRequest](w, r)
 	if !ok {
-		SendErrorResponse(w, "Invalid request", http.StatusBadRequest)
 		return
 	}
 
-	token := strings.TrimSpace(req.Token)
-	newPassword := strings.TrimSpace(req.NewPassword)
+	token := strings.TrimSpace(request.Token)
+	newPassword := strings.TrimSpace(request.NewPassword)
 
 	if token == "" {
 		SendErrorResponse(w, "Token is required", http.StatusBadRequest)
@@ -316,13 +311,12 @@ func (h *AuthHandler) UpdateEmail(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	req, ok := GetValidatedDTO[dto.UpdateEmailRequest](r)
+	request, ok := GetValidatedDTO[dto.UpdateEmailRequest](w, r)
 	if !ok {
-		SendErrorResponse(w, "Invalid request", http.StatusBadRequest)
 		return
 	}
 
-	email := strings.TrimSpace(req.Email)
+	email := strings.TrimSpace(request.Email)
 
 	user, err := h.authService.UpdateEmail(userID, email)
 	if err != nil {
@@ -362,13 +356,12 @@ func (h *AuthHandler) UpdateUsername(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	req, ok := GetValidatedDTO[dto.UpdateUsernameRequest](r)
+	request, ok := GetValidatedDTO[dto.UpdateUsernameRequest](w, r)
 	if !ok {
-		SendErrorResponse(w, "Invalid request", http.StatusBadRequest)
 		return
 	}
 
-	username := strings.TrimSpace(req.Username)
+	username := strings.TrimSpace(request.Username)
 
 	user, err := h.authService.UpdateUsername(userID, username)
 	if err != nil {
@@ -403,14 +396,13 @@ func (h *AuthHandler) UpdatePassword(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	req, ok := GetValidatedDTO[dto.UpdatePasswordRequest](r)
+	request, ok := GetValidatedDTO[dto.UpdatePasswordRequest](w, r)
 	if !ok {
-		SendErrorResponse(w, "Invalid request", http.StatusBadRequest)
 		return
 	}
 
-	currentPassword := strings.TrimSpace(req.CurrentPassword)
-	newPassword := strings.TrimSpace(req.NewPassword)
+	currentPassword := strings.TrimSpace(request.CurrentPassword)
+	newPassword := strings.TrimSpace(request.NewPassword)
 
 	user, err := h.authService.UpdatePassword(userID, currentPassword, newPassword)
 	if err != nil {
@@ -468,20 +460,19 @@ func (h *AuthHandler) DeleteAccount(w http.ResponseWriter, r *http.Request) {
 // @Failure 500 {object} AuthResponse "Internal server error"
 // @Router /api/auth/account/confirm [post]
 func (h *AuthHandler) ConfirmAccountDeletion(w http.ResponseWriter, r *http.Request) {
-	req, ok := GetValidatedDTO[dto.ConfirmAccountDeletionRequest](r)
+	request, ok := GetValidatedDTO[dto.ConfirmAccountDeletionRequest](w, r)
 	if !ok {
-		SendErrorResponse(w, "Invalid request", http.StatusBadRequest)
 		return
 	}
 
-	token := strings.TrimSpace(req.Token)
+	token := strings.TrimSpace(request.Token)
 
 	if token == "" {
 		SendErrorResponse(w, "Deletion token is required", http.StatusBadRequest)
 		return
 	}
 
-	if err := h.authService.ConfirmAccountDeletionWithPosts(token, req.DeletePosts); err != nil {
+	if err := h.authService.ConfirmAccountDeletionWithPosts(token, request.DeletePosts); err != nil {
 		switch {
 		case errors.Is(err, services.ErrInvalidDeletionToken):
 			SendErrorResponse(w, "This deletion link is invalid or has expired.", http.StatusBadRequest)
@@ -489,7 +480,7 @@ func (h *AuthHandler) ConfirmAccountDeletion(w http.ResponseWriter, r *http.Requ
 			SendErrorResponse(w, "Account deletion isn't available right now because email delivery is disabled.", http.StatusServiceUnavailable)
 		case errors.Is(err, services.ErrDeletionEmailFailed):
 			responseDTO := dto.AccountDeletionResponseDTO{
-				PostsDeleted: req.DeletePosts,
+				PostsDeleted: request.DeletePosts,
 			}
 			SendSuccessResponse(w, "Your account has been deleted, but we couldn't send the confirmation email.", responseDTO)
 		default:
@@ -499,7 +490,7 @@ func (h *AuthHandler) ConfirmAccountDeletion(w http.ResponseWriter, r *http.Requ
 	}
 
 	responseDTO := dto.AccountDeletionResponseDTO{
-		PostsDeleted: req.DeletePosts,
+		PostsDeleted: request.DeletePosts,
 	}
 	SendSuccessResponse(w, "Your account has been deleted.", responseDTO)
 }
@@ -530,18 +521,17 @@ func (h *AuthHandler) Logout(w http.ResponseWriter, r *http.Request) {
 // @Failure 500 {object} AuthResponse "Internal server error"
 // @Router /api/auth/refresh [post]
 func (h *AuthHandler) RefreshToken(w http.ResponseWriter, r *http.Request) {
-	req, ok := GetValidatedDTO[dto.RefreshTokenRequest](r)
+	request, ok := GetValidatedDTO[dto.RefreshTokenRequest](w, r)
 	if !ok {
-		SendErrorResponse(w, "Invalid request", http.StatusBadRequest)
 		return
 	}
 
-	if req.RefreshToken == "" {
+	if request.RefreshToken == "" {
 		SendErrorResponse(w, "Refresh token is required", http.StatusBadRequest)
 		return
 	}
 
-	result, err := h.authService.RefreshAccessToken(req.RefreshToken)
+	result, err := h.authService.RefreshAccessToken(request.RefreshToken)
 	if !HandleServiceError(w, err, "Token refresh failed", http.StatusInternalServerError) {
 		return
 	}
@@ -563,18 +553,17 @@ func (h *AuthHandler) RefreshToken(w http.ResponseWriter, r *http.Request) {
 // @Failure 500 {object} AuthResponse "Internal server error"
 // @Router /api/auth/revoke [post]
 func (h *AuthHandler) RevokeToken(w http.ResponseWriter, r *http.Request) {
-	req, ok := GetValidatedDTO[dto.RevokeTokenRequest](r)
+	request, ok := GetValidatedDTO[dto.RevokeTokenRequest](w, r)
 	if !ok {
-		SendErrorResponse(w, "Invalid request", http.StatusBadRequest)
 		return
 	}
 
-	if req.RefreshToken == "" {
+	if request.RefreshToken == "" {
 		SendErrorResponse(w, "Refresh token is required", http.StatusBadRequest)
 		return
 	}
 
-	err := h.authService.RevokeRefreshToken(req.RefreshToken)
+	err := h.authService.RevokeRefreshToken(request.RefreshToken)
 	if err != nil {
 		SendErrorResponse(w, "Failed to revoke token", http.StatusInternalServerError)
 		return

internal/handlers/auth_handler_test.go

@@ -693,7 +693,7 @@ func TestAuthHandlerUpdateEmail(t *testing.T) {
 			userID:         1,
 			mockSetup:      func(repo *testutils.UserRepositoryStub) {},
 			expectedStatus: http.StatusBadRequest,
-			expectedError:  "Invalid request",
+			expectedError:  "Invalid JSON",
 		},
 		{
 			name:           "empty email",
@@ -876,7 +876,7 @@ func TestAuthHandlerUpdatePassword(t *testing.T) {
 			userID:         1,
 			mockSetup:      func(repo *testutils.UserRepositoryStub) {},
 			expectedStatus: http.StatusBadRequest,
-			expectedError:  "Current password is required",
+			expectedError:  "CurrentPassword is required",
 		},
 		{
 			name:           "empty new password",
@@ -884,7 +884,7 @@ func TestAuthHandlerUpdatePassword(t *testing.T) {
 			userID:         1,
 			mockSetup:      func(repo *testutils.UserRepositoryStub) {},
 			expectedStatus: http.StatusBadRequest,
-			expectedError:  "Password is required",
+			expectedError:  "NewPassword is required",
 		},
 		{
 			name:           "short new password",
@@ -892,7 +892,7 @@ func TestAuthHandlerUpdatePassword(t *testing.T) {
 			userID:         1,
 			mockSetup:      func(repo *testutils.UserRepositoryStub) {},
 			expectedStatus: http.StatusBadRequest,
-			expectedError:  "Password must be at least 8 characters long",
+			expectedError:  "NewPassword must be at least 8 characters",
 		},
 		{
 			name:        "incorrect current password",
@@ -1042,13 +1042,13 @@ func TestAuthHandlerResendVerificationEmail(t *testing.T) {
 			name:           "invalid json",
 			body:           "not-json",
 			expectedStatus: http.StatusBadRequest,
-			expectedError:  "Invalid request",
+			expectedError:  "Invalid JSON",
 		},
 		{
 			name:           "missing email",
 			body:           `{}`,
 			expectedStatus: http.StatusBadRequest,
-			expectedError:  "Email address is required",
+			expectedError:  "Email is required",
 		},
 		{
 			name: "account not found",
@@ -1167,13 +1167,13 @@ func TestAuthHandlerConfirmAccountDeletion(t *testing.T) {
 			name:           "invalid json",
 			body:           "not-json",
 			expectedStatus: http.StatusBadRequest,
-			expectedError:  "Invalid request",
+			expectedError:  "Invalid JSON",
 		},
 		{
 			name:           "missing token",
 			body:           `{}`,
 			expectedStatus: http.StatusBadRequest,
-			expectedError:  "Deletion token is required",
+			expectedError:  "Token is required",
 		},
 		{
 			name: "invalid token from service",

internal/handlers/common.go

@@ -15,6 +15,7 @@ import (
 	"goyco/internal/dto"
 	"goyco/internal/middleware"
 	"goyco/internal/services"
+	"goyco/internal/validation"
 
 	"github.com/go-chi/chi/v5"
 	"gorm.io/gorm"
@@ -272,13 +273,51 @@ func HandleServiceError(w http.ResponseWriter, err error, defaultMsg string, def
 	return false
 }
 
-func GetValidatedDTO[T any](r *http.Request) (*T, bool) {
+func GetValidatedDTO[T any](w http.ResponseWriter, r *http.Request) (*T, bool) {
 	dtoVal := middleware.GetValidatedDTOFromContext(r.Context())
-	if dtoVal == nil {
-		return nil, false
+	dtoTypeInContext := middleware.GetDTOTypeFromContext(r.Context())
+
+	var dto *T
+	needsValidation := false
+
+	if dtoVal != nil {
+		var ok bool
+		dto, ok = dtoVal.(*T)
+		if !ok {
+			return nil, false
+		}
+		if dtoTypeInContext == nil {
+			needsValidation = true
+		}
+	} else {
+		var decoded T
+		if err := json.NewDecoder(r.Body).Decode(&decoded); err != nil {
+			SendErrorResponse(w, "Invalid JSON", http.StatusBadRequest)
+			return nil, false
+		}
+		dto = &decoded
+		needsValidation = true
 	}
-	dto, ok := dtoVal.(*T)
-	return dto, ok
+
+	if needsValidation {
+		if err := validation.ValidateStruct(dto); err != nil {
+			var errorMessages []string
+			if structErr, ok := err.(*validation.StructValidationError); ok {
+				errorMessages = make([]string, len(structErr.Errors))
+				for i, fieldError := range structErr.Errors {
+					errorMessages[i] = fieldError.Message
+				}
+			} else {
+				errorMessages = []string{err.Error()}
+			}
+
+			errorMsg := strings.Join(errorMessages, "; ")
+			SendErrorResponse(w, errorMsg, http.StatusBadRequest)
+			return nil, false
+		}
+	}
+
+	return dto, true
 }
 
 func WithValidation[T any](validationMiddleware func(http.Handler) http.Handler, handler http.HandlerFunc) http.HandlerFunc {

internal/handlers/post_handler.go

@@ -109,9 +109,8 @@ func (h *PostHandler) GetPost(w http.ResponseWriter, r *http.Request) {
 // @Failure 500 {object} PostResponse "Internal server error"
 // @Router /api/posts [post]
 func (h *PostHandler) CreatePost(w http.ResponseWriter, r *http.Request) {
-	req, ok := GetValidatedDTO[dto.CreatePostRequest](r)
+	request, ok := GetValidatedDTO[dto.CreatePostRequest](w, r)
 	if !ok {
-		SendErrorResponse(w, "Invalid request", http.StatusBadRequest)
 		return
 	}
 
@@ -120,9 +119,9 @@ func (h *PostHandler) CreatePost(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	title := security.SanitizeInput(req.Title)
-	url := security.SanitizeURL(req.URL)
-	content := security.SanitizePostContent(req.Content)
+	title := security.SanitizeInput(request.Title)
+	url := security.SanitizeURL(request.URL)
+	content := security.SanitizePostContent(request.Content)
 
 	if url == "" {
 		SendErrorResponse(w, "Invalid URL", http.StatusBadRequest)
@@ -263,14 +262,13 @@ func (h *PostHandler) UpdatePost(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	req, ok := GetValidatedDTO[dto.UpdatePostRequest](r)
+	request, ok := GetValidatedDTO[dto.UpdatePostRequest](w, r)
 	if !ok {
-		SendErrorResponse(w, "Invalid request", http.StatusBadRequest)
 		return
 	}
 
-	title := security.SanitizeInput(req.Title)
-	content := security.SanitizePostContent(req.Content)
+	title := security.SanitizeInput(request.Title)
+	content := security.SanitizePostContent(request.Content)
 
 	post.Title = title
 	post.Content = content

internal/handlers/post_handler_test.go

@@ -277,7 +277,7 @@ func TestPostHandlerCreatePostSuccess(t *testing.T) {
 
 	handler := NewPostHandler(repo, fetcher, nil)
 
-	request := createCreatePostRequest(`{"title":"  ","url":"https://example.com","content":"Go"}`)
+	request := createCreatePostRequest(`{"title":"","url":"https://example.com","content":"Go"}`)
 	ctx := context.WithValue(request.Context(), middleware.UserIDKey, uint(42))
 	request = request.WithContext(ctx)
 
@@ -310,7 +310,7 @@ func TestPostHandlerCreatePostValidation(t *testing.T) {
 	}
 
 	recorder = httptest.NewRecorder()
-	request = createCreatePostRequest(`{"title":"ok","url":"https://example.com"}`)
+	request = createCreatePostRequest(`{"title":"okay","url":"https://example.com"}`)
 	handler.CreatePost(recorder, request)
 	testutils.AssertHTTPStatus(t, recorder, http.StatusUnauthorized)
 }
@@ -334,7 +334,7 @@ func TestPostHandlerCreatePostTitleFetcherErrors(t *testing.T) {
 				return "", tc.err
 			}}
 			handler := NewPostHandler(repo, fetcher, nil)
-			request := createCreatePostRequest(`{"title":" ","url":"https://example.com"}`)
+			request := createCreatePostRequest(`{"title":"","url":"https://example.com"}`)
 			request = request.WithContext(context.WithValue(request.Context(), middleware.UserIDKey, uint(1)))
 
 			recorder := httptest.NewRecorder()

internal/handlers/user_handler.go

@@ -93,13 +93,12 @@ func (h *UserHandler) GetUser(w http.ResponseWriter, r *http.Request) {
 // @Failure 500 {object} UserResponse "Internal server error"
 // @Router /api/users [post]
 func (h *UserHandler) CreateUser(w http.ResponseWriter, r *http.Request) {
-	req, ok := GetValidatedDTO[dto.RegisterRequest](r)
+	request, ok := GetValidatedDTO[dto.RegisterRequest](w, r)
 	if !ok {
-		SendErrorResponse(w, "Invalid request", http.StatusBadRequest)
 		return
 	}
 
-	result, err := h.authService.Register(req.Username, req.Email, req.Password)
+	result, err := h.authService.Register(request.Username, request.Email, request.Password)
 	if err != nil {
 		var validationErr *validation.ValidationError
 		if errors.As(err, &validationErr) {

internal/handlers/vote_handler.go

@@ -78,14 +78,13 @@ func (h *VoteHandler) CastVote(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	req, ok := GetValidatedDTO[dto.CastVoteRequest](r)
+	request, ok := GetValidatedDTO[dto.CastVoteRequest](w, r)
 	if !ok {
-		SendErrorResponse(w, "Invalid request", http.StatusBadRequest)
 		return
 	}
 
 	var voteType database.VoteType
-	switch req.Type {
+	switch request.Type {
 	case "up":
 		voteType = database.VoteUp
 	case "down":