Files
tp/serv_nginx/serv_golang_rest_api/internal/utils/json.go
T

115 lines
3.3 KiB
Go

// utils/json.go
package utils
import (
"encoding/json"
"errors"
"fmt"
"io"
"net/http"
"strings"
)
// DecodeJSON декодирует JSON из тела запроса с валидацией
func DecodeJSON(r *http.Request, v interface{}) error {
// Ограничиваем размер тела запроса (например, 1MB)
maxBytes := int64(1_048_576) // 1MB
r.Body = http.MaxBytesReader(nil, r.Body, maxBytes)
decoder := json.NewDecoder(r.Body)
decoder.DisallowUnknownFields() // Запрещаем неизвестные поля
err := decoder.Decode(v)
if err != nil {
var syntaxError *json.SyntaxError
var unmarshalTypeError *json.UnmarshalTypeError
var invalidUnmarshalError *json.InvalidUnmarshalError
switch {
case err == io.EOF:
return &APIError{
Code: http.StatusBadRequest,
Message: "Request body is empty",
}
case err.Error() == "http: request body too large":
return &APIError{
Code: http.StatusRequestEntityTooLarge,
Message: fmt.Sprintf("Request body must not be larger than %d bytes", maxBytes),
}
case strings.HasPrefix(err.Error(), "json: unknown field"):
fieldName := strings.TrimPrefix(err.Error(), "json: unknown field ")
return &APIError{
Code: http.StatusBadRequest,
Message: fmt.Sprintf("Unknown field in JSON: %s", fieldName),
}
case errors.As(err, &syntaxError):
return &APIError{
Code: http.StatusBadRequest,
Message: fmt.Sprintf("Malformed JSON at position %d", syntaxError.Offset),
}
case errors.As(err, &unmarshalTypeError):
return &APIError{
Code: http.StatusBadRequest,
Message: fmt.Sprintf("Invalid value for field '%s'. Expected type %s", unmarshalTypeError.Field, unmarshalTypeError.Type),
}
case errors.As(err, &invalidUnmarshalError):
return &APIError{
Code: http.StatusInternalServerError,
Message: "Internal server error",
}
default:
return &APIError{
Code: http.StatusBadRequest,
Message: "Invalid JSON",
}
}
}
// Проверяем, что нет лишних данных после JSON
if err = decoder.Decode(&struct{}{}); err != io.EOF {
return &APIError{
Code: http.StatusBadRequest,
Message: "Request body must contain only single JSON object",
}
}
return nil
}
// WriteJSON записывает JSON ответ
func WriteJSON(w http.ResponseWriter, status int, data interface{}) error {
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(status)
if data == nil {
return nil
}
encoder := json.NewEncoder(w)
encoder.SetEscapeHTML(true) // Экранируем HTML для безопасности
return encoder.Encode(data)
}
// WriteError записывает ошибку в формате JSON
func WriteError(w http.ResponseWriter, status int, message string) {
errorResponse := ErrorResponse{
Error: true,
Message: message,
Code: status,
}
WriteJSON(w, status, errorResponse)
}
// WriteValidationError записывает ошибки валидации
func WriteValidationError(w http.ResponseWriter, errors map[string]string) {
errorResponse := ValidationErrorResponse{
Error: true,
Message: "Validation failed",
Code: http.StatusBadRequest,
Errors: errors,
}
WriteJSON(w, http.StatusBadRequest, errorResponse)
}