Golang + MongoDB embedded type (embedding a struct in another struct)

Question

Hypothetical, I run an API and when a user makes a GET request on the user resource, I will return relevant fields as a JSON

type User struct {
  Id      bso         


        

Answer 1

Another alternative would be to declare an interface.

type SecureModel interface {
    SecureMe()
}

Make sure your model implements it:

type User struct {
    Id       bson.ObjectId `json:"id,omitempty" bson:"_id,omitempty"`
    Username string        `json:"username" bson:"username"`
    Secret   string        `json:"secret,omitempty" bson:"secret"`
}

func (u *User) SecureMe() {
    u.Secret = ""
}

And only call it depending on which route is called.

// I am being sent to a non-admin, secure me.
if _, ok := user.(SecureModel); ok {
    user.(SecureModel).SecureMe()
}
// Marshall to JSON, etc.
...

Edit: The reason for using an interface here is for cases where you might send arbitrary models over the wire using a common method.

Answer 2

You should take a look at the bson package's inline flag (that is documented under bson.Marshal). It should allow you to do something like this:

type adminUser struct {
    User `bson:",inline"`
    Secret string `json:"secret,omitempty" bson:"secret,omitempty"`
}

However, now you'll notice that you get duplicate key errors when you try to read from the database with this structure, since both adminUser and User contain the key secret.

In your case I would remove the Secret field from User and only have the one in adminUser. Then whenever you need to write to the secret field, make sure you use an adminUser.