Empty model on BeforeInsert hook

[jpascal]

My User model

type User struct {
	ID        uuid.UUID `gorm:"default:uuid_generate_v4();->"`
	CreatedAt time.Time
	UpdatedAt time.Time
	Admin          bool
}
func (u *User) BeforeInsert(ctx context.Context, query *bun.InsertQuery) error {
  // u.Email => "" not "user@domain.local"
  u.CreatedAt = time.Now()
  u.UpdatedAt = time.Now()
 return nil
}

var signUpUser = &User{
   Email: "user@domain.local"
}
tx.NewInsert().Model(signUpUser).Exec(ctx)

INSERT INTO "users" ("id", "created_at", "updated_at", "email") VALUES (DEFAULT, '0001-01-01 00:00:00+00:00', '0001-01-01 00:00:00+00:00', '', 'user@domain.local') RETURNING "id"

created_at => 0
updated_at => 0

Why I must use query.GetModel() all time instead use self object?

I have this code:

type ChainHookFn func(context.Context) error

func HooksChain(ctx context.Context, hookFns ...ChainHookFn) error {
	for _, hookFn := range hookFns {
		if err := hookFn(ctx); err != nil {
			return err
		}
	}
	return nil
}

I have hook chains in my models and all was good)

func (u *User) BeforeUpdate(ctx context.Context, query *bun.UpdateQuery) error {
	return HooksChain(ctx, u.updatePassword, u.validate)
}
func (u *User) updatePassword(_ context.Context) error {
	if len(u.Password) > 0 {
		if result, err := bcrypt.GenerateFromPassword([]byte(u.Password), bcrypt.DefaultCost); err != nil {
			return err
		} else {
			u.HashedPassword = string(result)
		}
	}
	return nil
}

func (u User) validate(ctx context.Context) error {
	validators := []*validator.Validator{
		validator.Validate("email", u.Email).Rules(
			rules.IsPresence(),
			rules.IsEmail()
		),
	}
	if len(u.HashedPassword) == 0 {
		validators = append(validators, validator.Validate("password", u.Password).Rules(
			rules.IsPresence(),
		))
	}
	return validator.Scope(validators...).Validate(ctx)
}

I can create long hook-chains for each models by logic.
After update, I must all time use query.Get Model().Value().(*SomeModel) boilerplate... :( and must thinking about type casting.

[vmihailenco]

Why I must use query.GetModel() all time instead use self object?

Because Bun also works with slice-based models, e.g. *[]User. And in some cases it might be useful to have access to a whole slice.

---

Overall it is best to only use hooks as a last resort when everything else fails. In your case you should create InsertUser func and have everything there.

[vmihailenco]

Also see https://bun.uptrace.dev/guide/hooks.html#disclaimer

[jpascal]

Overall it is best to only use hooks as a last resort when everything else fails. In your case you should create InsertUser func and have everything there.

If I will create function Insert User and for other operations like this, then I didn't see some profit from model hooks overall. ) May be model hooks in this lib must not to be? :)

[jpascal]

Another case...
I have models User and Profile.
One logic need to create user directly, other need create user and profile inside transaction. In this case I must realize InsertUser(bun.DB), InsertUserTx(bun.Tx), InsertProfile(bun.DB), InsertProfileTx(bun.Tx), ... a lot of code ... In old variant of hooks all work perfectly.

[jpascal]

Better example for https://bun.uptrace.dev/guide/hooks.html#disclaimer

func UpdateUser(ctx context.Context, query bun.UpdateQuery, user *User) error { ... }
func InsertUser(ctx context.Context, query bun.InsertQuery, user *User) error { ... }

[vmihailenco]

I am not sure sure how you managed transactions with hooks, but that does not sound right :)

A better solution would be to create a common interface for bun.DB and bun.Tx. They both have methods like NewSelect and NewInsert so you can pass a tx instead of db:

tx := db.Begin()
InsertUser(ctx, tx)
InsertProfile(ctx, tx)
tx.Commit()

I guess Bun must provide such interface.

May be model hooks in this lib must not to be? :)

Ideally, yes. Practically you should not use hooks for such common things like transactions and validation.

[vmihailenco]

IDB was added in v0.2.1. See https://github.com/uptrace/bun/tree/master/example/tx-composition