Discussion about use cases

[vladiulianbogdan]

Hello! Thank you for this repo, it is really helpful. 🎉

I want to ask you about the responsibilities of use cases and controller. If I understood correctly, the controller should have the responsibility of sanitising the input from the route, calling the use case and then returning the response. The use case is the one that contains the business logic.

However, the login use case, is just a wrapper around UserRepository and the actual business logic happens in the LoginController:

[...]
user, err := lc.LoginUsecase.GetUserByEmail(c, request.Email)
	if err != nil {
		c.JSON(http.StatusNotFound, domain.ErrorResponse{Message: "User not found with the given email"})
		return
	}

	if bcrypt.CompareHashAndPassword([]byte(user.Password), []byte(request.Password)) != nil {
		c.JSON(http.StatusUnauthorized, domain.ErrorResponse{Message: "Invalid credentials"})
		return
	}

	accessToken, err := lc.LoginUsecase.CreateAccessToken(&user, lc.Env.AccessTokenSecret, lc.Env.AccessTokenExpiryHour)
	if err != nil {
		c.JSON(http.StatusInternalServerError, domain.ErrorResponse{Message: err.Error()})
		return
	}

	refreshToken, err := lc.LoginUsecase.CreateRefreshToken(&user, lc.Env.RefreshTokenSecret, lc.Env.RefreshTokenExpiryHour)
	if err != nil {
		c.JSON(http.StatusInternalServerError, domain.ErrorResponse{Message: err.Error()})
		return
	}
[...]

Here, the controller decides that first we should fetch the user, then we check if the password is correct and if it is, we generate both an access token and a refresh token. This is the business logic of a login and I feel like it should be in the use case.

[marcosvidolin]

Just bringing up a point for discussion. I've noticed that the use cases have multiple responsibilities, as seen in the case of LoginUsecase. This use case encompasses various functions: GetUserByEmail, CreateAccessToken, CreateRefreshToken...

From my perspective, Login itself should already be a use case.

loginUsecase = usecase.NewLoginUsecase()
loginUsecase.execute()

Whats your thoughts?

[Redarcher9]

Hello! Thank you for this repo, it is really helpful. 🎉

I want to ask you about the responsibilities of use cases and controller. If I understood correctly, the controller should have the responsibility of sanitising the input from the route, calling the use case and then returning the response. The use case is the one that contains the business logic.

However, the login use case, is just a wrapper around UserRepository and the actual business logic happens in the LoginController:

[...]
user, err := lc.LoginUsecase.GetUserByEmail(c, request.Email)
	if err != nil {
		c.JSON(http.StatusNotFound, domain.ErrorResponse{Message: "User not found with the given email"})
		return
	}

	if bcrypt.CompareHashAndPassword([]byte(user.Password), []byte(request.Password)) != nil {
		c.JSON(http.StatusUnauthorized, domain.ErrorResponse{Message: "Invalid credentials"})
		return
	}

	accessToken, err := lc.LoginUsecase.CreateAccessToken(&user, lc.Env.AccessTokenSecret, lc.Env.AccessTokenExpiryHour)
	if err != nil {
		c.JSON(http.StatusInternalServerError, domain.ErrorResponse{Message: err.Error()})
		return
	}

	refreshToken, err := lc.LoginUsecase.CreateRefreshToken(&user, lc.Env.RefreshTokenSecret, lc.Env.RefreshTokenExpiryHour)
	if err != nil {
		c.JSON(http.StatusInternalServerError, domain.ErrorResponse{Message: err.Error()})
		return
	}
[...]

Here, the controller decides that first we should fetch the user, then we check if the password is correct and if it is, we generate both an access token and a refresh token. This is the business logic of a login and I feel like it should be in the use case.

Will it be a good idea to implement all the repository related functions in usecase and use the controller only for sanitising the input from the route, calling the use case and then returning the response?