feat: add data validation and structured logging

internal/api/auth_handler.go

@@ -8,6 +8,7 @@ import (
 
 	"gitea.mrixs.me/minecraft-platform/backend/internal/core"
 	"gitea.mrixs.me/minecraft-platform/backend/internal/models"
+	"gitea.mrixs.me/minecraft-platform/backend/internal/utils"
 )
 
 type AuthHandler struct {
@@ -27,6 +28,13 @@ func (h *AuthHandler) Authenticate(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	if validationErrors := utils.ValidateStruct(req); validationErrors != nil {
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusBadRequest)
+		json.NewEncoder(w).Encode(validationErrors)
+		return
+	}
+
 	response, err := h.Service.Authenticate(r.Context(), req)
 	if err != nil {
 		if errors.Is(err, core.ErrInvalidCredentials) {
@@ -57,6 +65,13 @@ func (h *AuthHandler) Join(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	if validationErrors := utils.ValidateStruct(req); validationErrors != nil {
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusBadRequest)
+		json.NewEncoder(w).Encode(validationErrors)
+		return
+	}
+
 	err := h.Service.ValidateJoinRequest(r.Context(), req)
 	if err != nil {
 		if errors.Is(err, core.ErrInvalidCredentials) {
@@ -84,6 +99,13 @@ func (h *AuthHandler) Login(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	if validationErrors := utils.ValidateStruct(req); validationErrors != nil {
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusBadRequest)
+		json.NewEncoder(w).Encode(validationErrors)
+		return
+	}
+
 	token, user, err := h.Service.LoginUser(r.Context(), req)
 	if err != nil {
 		if errors.Is(err, core.ErrInvalidCredentials) {

internal/api/user_handler.go

@@ -4,11 +4,13 @@ import (
 	"encoding/json"
 	"errors"
 	"log"
+	"log/slog"
 	"net/http"
 
 	"gitea.mrixs.me/minecraft-platform/backend/internal/core"
 	"gitea.mrixs.me/minecraft-platform/backend/internal/database"
 	"gitea.mrixs.me/minecraft-platform/backend/internal/models"
+	"gitea.mrixs.me/minecraft-platform/backend/internal/utils"
 	"github.com/golang-jwt/jwt/v5"
 )
 
@@ -23,13 +25,18 @@ func (h *UserHandler) Register(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	// --- ДОБАВЛЕНО ЛОГИРОВАНИЕ ---
-	log.Printf("[Handler] Received registration request for username: '%s', email: '%s'", req.Username, req.Email)
+	if validationErrors := utils.ValidateStruct(req); validationErrors != nil {
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusBadRequest)
+		json.NewEncoder(w).Encode(validationErrors)
+		return
+	}
+
+	slog.Info("Received registration request", "username", req.Username, "email", req.Email)
 
 	err := h.Service.RegisterNewUser(r.Context(), req)
 	if err != nil {
-		// --- ДОБАВЛЕНО ЛОГИРОВАНИЕ ОШИБКИ ---
-		log.Printf("[Handler] Service returned error: %v", err)
+		slog.Error("Service returned error", "error", err)
 
 		switch {
 		case errors.Is(err, database.ErrUserExists):
@@ -42,8 +49,7 @@ func (h *UserHandler) Register(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	// --- ДОБАВЛЕНО ЛОГИРОВАНИЕ УСПЕХА ---
-	log.Printf("[Handler] User '%s' registered successfully.", req.Username)
+	slog.Info("User registered successfully", "username", req.Username)
 	w.WriteHeader(http.StatusCreated)
 }
 

internal/models/auth.go

@@ -9,8 +9,8 @@ type Agent struct {
 // AuthenticateRequest - это тело запроса на /authserver/authenticate
 type AuthenticateRequest struct {
 	Agent       Agent  `json:"agent"`
-	Username    string `json:"username"`
-	Password    string `json:"password"`
+	Username    string `json:"username" validate:"required"`
+	Password    string `json:"password" validate:"required"`
 	ClientToken string `json:"clientToken"`
 }
 
@@ -70,15 +70,15 @@ type SessionProfileResponse struct {
 
 // JoinRequest - это тело запроса на /sessionserver/session/minecraft/join
 type JoinRequest struct {
-	AccessToken     string `json:"accessToken"`
-	SelectedProfile string `json:"selectedProfile"` // UUID пользователя без дефисов
-	ServerID        string `json:"serverId"`
+	AccessToken     string `json:"accessToken" validate:"required"`
+	SelectedProfile string `json:"selectedProfile" validate:"required"` // UUID пользователя без дефисов
+	ServerID        string `json:"serverId" validate:"required"`
 }
 
 // LoginRequest - это тело запроса на /api/login
 type LoginRequest struct {
-	Login    string `json:"login"`
-	Password string `json:"password"`
+	Login    string `json:"login" validate:"required"`
+	Password string `json:"password" validate:"required"`
 }
 
 // LoginResponse - это тело успешного ответа с JWT

internal/models/user.go

@@ -20,9 +20,9 @@ type User struct {
 
 // RegisterRequest определяет структуру JSON-запроса на регистрацию
 type RegisterRequest struct {
-	Username string `json:"username"`
-	Email    string `json:"email"`
-	Password string `json:"password"`
+	Username string `json:"username" validate:"required,min=3,max=16,alphanum"`
+	Email    string `json:"email" validate:"required,email"`
+	Password string `json:"password" validate:"required,min=8"`
 }
 type Profile struct {
 	ID        int       `json:"-"`

internal/utils/validator.go

@@ -0,0 +1,47 @@
+package utils
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/go-playground/validator/v10"
+)
+
+var validate *validator.Validate
+
+func init() {
+	validate = validator.New()
+}
+
+// ValidationErrorResponse represents the structure of validation errors returned to the client
+type ValidationErrorResponse struct {
+	Errors map[string]string `json:"errors"`
+}
+
+// ValidateStruct validates a struct based on its tags using go-playground/validator
+func ValidateStruct(s interface{}) *ValidationErrorResponse {
+	err := validate.Struct(s)
+	if err != nil {
+		var errorsMap = make(map[string]string)
+		for _, err := range err.(validator.ValidationErrors) {
+			// Simpler error messages for now. Can be enhanced with universal-translator.
+			fieldName := strings.ToLower(err.Field())
+			switch err.Tag() {
+			case "required":
+				errorsMap[fieldName] = fmt.Sprintf("Field '%s' is required", fieldName)
+			case "email":
+				errorsMap[fieldName] = fmt.Sprintf("Field '%s' must be a valid email", fieldName)
+			case "min":
+				errorsMap[fieldName] = fmt.Sprintf("Field '%s' must be at least %s characters long", fieldName, err.Param())
+			case "max":
+				errorsMap[fieldName] = fmt.Sprintf("Field '%s' must be at most %s characters long", fieldName, err.Param())
+			case "alphanum":
+				errorsMap[fieldName] = fmt.Sprintf("Field '%s' must contain only alphanumeric characters", fieldName)
+			default:
+				errorsMap[fieldName] = fmt.Sprintf("Field '%s' failed validation on '%s' tag", fieldName, err.Tag())
+			}
+		}
+		return &ValidationErrorResponse{Errors: errorsMap}
+	}
+	return nil
+}