接口无法使用方法，即使它们是相同类型的。

huangapple
go评论180阅读模式
英文:

Interface is unable to use method even though they are of the same type

问题

我有一个阶段性问题。在我看来，它看起来完全正确，但我的IDE一直显示这个错误，无法编译。

  1. Cannot use 'userRepo' (type *UserRepo) as the type UserRepository Type does not 
  2. implement 'UserRepository' need the method: GetByEmail(email string) (*User, error) 
  3. have the method: GetByEmail(email string) (*User, error)

UserRepository.go

  1. type UserRepo struct {
  2. 	db         *mongo.Client
  3. 	collection *mongo.Collection
  4. }
  6. func (m *UserRepo) GetByEmail(email string) (*User, error) {
  8. 	ctx := context.Background()
  10. 	var user *User
  11. 	err := m.collection.FindOne(ctx, bson.M{"username": email}).Decode(&user)
  12. 	if err != nil {
  13. 		return &User{}, err
  14. 	}
  16. 	return user, nil
  17. }
  19. func NewUserRepository(client *mongo.Client, collection *mongo.Collection) *UserRepo {
  20. 	return &UserRepo{
  21. 		db:         client,
  22. 		collection: collection,
  23. 	}
  24. }

LoginService.go

  1. type Login struct {
  2. 	helper    pkg.Helper
  3. 	user      User
  4. 	res       LoginResponse
  5. 	repo      Repository
  6. 	userRepo  UserRepository
  7. 	tokenRepo TokenRepository
  8. 	cfg       config.Config
  9. 	validator *validator.Validator
  10. }
  12. type UserRepository interface {
  13. 	GetByEmail(email string) (*User, error)
  14. }
  16. func (l *Login) CreateAccountHandler(w http.ResponseWriter, r *http.Request) {
  18. 	......
  20. 	_, err = l.userRepo.GetByEmail(email)
  21. 	// Check if the username is already taken.
  22. 	if err != nil {
  23. 		http.Error(w, "Username already taken", http.StatusConflict)
  25. 		json.NewEncoder(w).Encode(failedResponse)
  26. 		return
  27. 	}
  28. }
  30. func NewLoginService(repository Repository, tokenRepo TokenRepository, userRepo UserRepository) *Login {
  31. 	return &Login{
  32. 		helper:    pkg.Helper{},
  33. 		repo:      repository,
  34. 		userRepo:  userRepo,
  35. 		tokenRepo: tokenRepo,
  36. 		validator: validator.New(),
  37. 	}
  38. }

方法名和类型都是相同的。

main.go

  1. // Login
  2. loginCollection := client.Database(cfg.MongoConfig.DBName).Collection(cfg.MongoConfig.LoginCollection)
  3. loginRepo := login.NewLoginRepository(client, loginCollection)
  4. usersCollection := client.Database(cfg.MongoConfig.DBName).Collection(cfg.UsersConfig.UserCollection)
  5. userRepo := data.NewUserRepository(client, usersCollection)
  6. loginService := login.NewLoginService(loginRepo, tokenRepo, userRepo) // 错误出现在这里 "userRepo"

以上是要翻译的内容。

英文:

I have a stage issue. It looks completely correct to me but my IDE keeps showing me this error and will not compile.

  1. Cannot use 'userRepo' (type *UserRepo) as the type UserRepository Type does not 
  2. implement 'UserRepository' need the method: GetByEmail(email string) (*User, error) 
  3. have the method: GetByEmail(email string) (*User, error)

UserRepository.go

  1. type UserRepo struct {
  2. 	db         *mongo.Client
  3. 	collection *mongo.Collection
  4. }
  7. func (m *UserRepo) GetByEmail(email string) (*User, error) {
  9. 	ctx := context.Background()
  11. 	var user *User
  12. 	err := m.collection.FindOne(ctx, bson.M{"username": email}).Decode(&user)
  13. 	if err != nil {
  14. 		return &User{}, err
  15. 	}
  17. 	return user, nil
  18. }
  20. func NewUserRepository(client *mongo.Client, collection *mongo.Collection) *UserRepo {
  21. 	return &UserRepo{
  22. 		db:         client,
  23. 		collection: collection,
  24. 	}
  25. }

LoginService.go

  1. type Login struct {
  2. 	helper    pkg.Helper
  3. 	user      User
  4. 	res       LoginResponse
  5. 	repo      Repository
  6. 	userRepo  UserRepository
  7. 	tokenRepo TokenRepository
  8. 	cfg       config.Config
  9. 	validator *validator.Validator
  10. }
  12. type UserRepository interface {
  13. 	GetByEmail(email string) (*User, error)
  14. }
  16. func (l *Login) CreateAccountHandler(w http.ResponseWriter, r *http.Request) {
  17. 	
  18.     .....
  20. 	_, err = l.userRepo.GetByEmail(email)
  21. 	// Check if the username is already taken.
  22. 	if err != nil {
  23. 		http.Error(w, "Username already taken", http.StatusConflict)
  25. 		json.NewEncoder(w).Encode(failedResponse)
  26. 		return
  27. 	}
  28. }
  30. func NewLoginService(repository Repository, tokenRepo TokenRepository, userRepo UserRepository) *Login {
  31. 	return &Login{
  32. 		helper:    pkg.Helper{},
  33. 		repo:      repository,
  34. 		userRepo:  userRepo,
  35. 		tokenRepo: tokenRepo,
  36. 		validator: validator.New(),
  37. 	}
  38. }

The method names are the same and the type..

main.go

  1. // Login
  2. 	loginCollection := client.Database(cfg.MongoConfig.DBName).Collection(cfg.MongoConfig.LoginCollection)
  3. 	loginRepo := login.NewLoginRepository(client, loginCollection)
  4. 	usersCollection := client.Database(cfg.MongoConfig.DBName).Collection(cfg.UsersConfig.UserCollection)
  5. 	userRepo := data.NewUserRepository(client, usersCollection)
  6. 	loginService := login.NewLoginService(loginRepo, tokenRepo, userRepo) <----- error is here "userRepo"

答案1

得分: 4

根据代码中的描述：

  1. userRepo := data.NewUserRepository(client, usersCollection)
  2. loginService := login.NewLoginService(loginRepo, tokenRepo, userRepo)

NewUserRepository 函数位于 data 包中，所以 GetByEmail(email string) (*User, error) 中的 *User 是 data.User 类型；而

NewLoginService 函数位于 login 包中，所以 UserRepository 接口中的 GetByEmail 中的 *User 是 login.User 类型。

data.User 和 login.User 是不同的类型，因此会出现错误。要纠正这个问题，可以修改函数或接口，使返回的类型来自同一个包。

英文:

Based on

  1. userRepo := data.NewUserRepository(client, usersCollection)
  2. loginService := login.NewLoginService(loginRepo, tokenRepo, userRepo)

NewUserRepository is in the package data so the *User in GetByEmail(email string) (*User, error) is a data.User whereas,

NewLoginService is in the package login so the *User in the GetByEmail within the UserRepository interface is a login.User.

data.User and login.User are different types hence the error. To correct this alter either the function or the interface such that the type returned is from the same package.

huangapple
  • 本文由 发表于 2023年7月29日 15:30:49
  • 转载请务必保留本文链接：https://go.coder-hub.com/76792518.html
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