refac: missing user or article is reported with a domain not-found error instead of a raw GORM error, and the API answers 404 for it

internal/domain/user/userDomain.go

@@ -1,9 +1,12 @@
 package user
 
 import (
+	"errors"
 	"time"
 )
 
+var ErrUserNotFound = errors.New("user not found")
+
 type User struct {
 	ID                     uint32    `json:"id"`
 	Username               string    `json:"username"`

internal/infrastructure/persistence/repositories/articleRepository.go

@@ -38,7 +38,7 @@ func (a *ArticleRepository) Get(id uint32) (domain.Article, error) {
 	var article entity.Article
 	err := a.db.Model(&entity.Article{}).Preload("Images").First(&article, id).Error
 	if err != nil {
-		return domain.Article{}, err
+		return domain.Article{}, mapNotFoundErr(err, domain.ErrArticleNotFound)
 	}
 
 	return mappers.ArticleToDomain(article), nil
@@ -48,7 +48,7 @@ func (a *ArticleRepository) GetByName(name string) (domain.Article, error) {
 	var article entity.Article
 	err := a.db.Model(&entity.Article{}).Where("title = ?", name).First(&article).Error
 	if err != nil {
-		return domain.Article{}, err
+		return domain.Article{}, mapNotFoundErr(err, domain.ErrArticleNotFound)
 	}
 
 	return mappers.ArticleToDomain(article), nil

internal/infrastructure/persistence/repositories/notFound.go

@@ -0,0 +1,14 @@
+package persistence
+
+import (
+	"errors"
+
+	"gorm.io/gorm"
+)
+
+func mapNotFoundErr(err error, sentinel error) error {
+	if errors.Is(err, gorm.ErrRecordNotFound) {
+		return sentinel
+	}
+	return err
+}

internal/infrastructure/persistence/repositories/userRepository.go

@@ -21,7 +21,7 @@ func (u *UserRepository) Get(id uint32) (domainUser.User, error) {
 	var localUser entity.User
 	err := u.db.Model(&entity.User{}).First(&localUser, id).Error
 	if err != nil {
-		return domainUser.User{}, err
+		return domainUser.User{}, mapNotFoundErr(err, domainUser.ErrUserNotFound)
 	}
 
 	return mappers.UserToDomain(localUser), nil
@@ -69,7 +69,7 @@ func (u *UserRepository) GetByUsername(username string) (domainUser.User, error)
 	var localUser entity.User
 	err := u.db.Model(&entity.User{}).Where("username = ?", username).First(&localUser).Error
 	if err != nil {
-		return domainUser.User{}, err
+		return domainUser.User{}, mapNotFoundErr(err, domainUser.ErrUserNotFound)
 	}
 
 	return mappers.UserToDomain(localUser), nil
@@ -79,7 +79,7 @@ func (u *UserRepository) GetByEmail(email string) (domainUser.User, error) {
 	var localUser entity.User
 	err := u.db.Model(&entity.User{}).Where("email = ?", email).First(&localUser).Error
 	if err != nil {
-		return domainUser.User{}, err
+		return domainUser.User{}, mapNotFoundErr(err, domainUser.ErrUserNotFound)
 	}
 
 	return mappers.UserToDomain(localUser), nil