changes...

internal/application/errors/db_error.go

@@ -0,0 +1,15 @@
+package errors
+
+type DBError struct {
+	msg string
+}
+
+func NewDBError(msg string) DBError {
+	return DBError{
+		msg: msg,
+	}
+}
+
+func (e *DBError) Error() string {
+	return e.msg
+}

internal/application/errors/not_found_error.go

@@ -0,0 +1,15 @@
+package errors
+
+type NotFoundError struct {
+	msg string
+}
+
+func NewNotFoundError(msg string) *NotFoundError {
+	return &NotFoundError{
+		msg: msg,
+	}
+}
+
+func (e *NotFoundError) Error() string {
+	return e.msg
+}

internal/application/services/post_service.go

@@ -3,6 +3,7 @@ package services
 import (
 	"58team_blog/internal/application/commands"
 	"58team_blog/internal/application/common"
+	ie "58team_blog/internal/application/errors"
 	"58team_blog/internal/application/mapper"
 	"58team_blog/internal/application/queries"
 	"58team_blog/internal/domain/entities"
@@ -44,6 +45,10 @@ func (s *PostService) FindById(query queries.PostFindByIdQuery) (*queries.PostFi
 		return nil, err
 	}
 
+	if post == nil {
+		return nil, ie.NewNotFoundError("Post")
+	}
+
 	if err := post.Validate(); err != nil {
 		return nil, err
 	}

internal/application/services/user_service.go

@@ -15,7 +15,7 @@ type UserService struct {
 	repo repository.UsersRepository
 }
 
-func NewUserService(repo repository.UsersRepository) UserService {
+func CreateUserService(repo repository.UsersRepository) UserService {
 	return UserService{
 		repo: repo,
 	}
@@ -26,7 +26,7 @@ func (s *UserService) Create(cmd commands.CreateUserCommand) (*common.UserResult
 	{
 		user, err := s.repo.FindByName(cmd.Username)
 		if err != nil {
-			return nil, err
+			return nil, fmt.Errorf("User.create findByName error: %s", err)
 		}
 
 		if user != nil {