Protobuf different messages for the same field

Question

is it possible to create a field that can hold different types of messages? Let's say I wanted to send a request to create a car, but it can have different types of windows in it, and each type requires different fields to be present:

message TintedWindows {
    double tintPercent = 1;
    string tintColor = 2;
}

message ArmoredWindows {
    string armorClass = 1;
}

message CreateCarRequest {
    string color = 1;
    int wheels = 2;
    int doors = 3;
    Windows??? windows = 4;
}

Is there a way of doing that smoothly or I have to add all those messages and check which one is empty and which one is not:

message CreateCarRequest {
    string color = 1;
    int wheels = 2;
    int doors = 3;
    TintedWindows tinted = 4;
    ArmoredWindows armored = 5;
}

then do: (pseudocode)


windowsInterface windows;

if req.tinted != null && req.armored == null {
   windows = newTinted(req.tinted)
} else if req.tinted == null && req.armored != null {
   windows = newArmored(req.armored)
} else {
   throw error
}

I'm curently doing that using the second method and it's a bit cumbersome.

Is https://stackoverflow.com/a/59568458/4690866 what you are looking for? Seems like Any or oneof is what you'd be looking for here. — Eric Anderson, Jan 03 '23 at 17:39

score 2 · Answer 1 · answered Jan 02 '23 at 21:55

You can use Oneof.

message CreateCarRequest {
    string color = 1;
    uint32 wheels = 2;
    uint32 doors = 3;
    oneof windows {
        TintedWindows tinted = 4;
        ArmoredWindows armored = 5;
    }
}

There is no int type (see scalar), you'll need to choose one of the available types, probably uint32 for number of wheels and doors.

Protobuf different messages for the same field

1 Answers1