Edit Players data by own backend Node server

Unity Services
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1

Hello guys,

I’m implementing chest purchasing in my game, my idea was to send a request sending which Chest to open, and the playerId from the AuthenticationServices from Unity, and in my own node backend, I would check if the player has enough Currency sending requests to Unity API, and so, I would make the math and all things that would be necessary, like decrease the players currency amount, however I realized that Unity doesn’t allow to change a player data by an own backend service, is that correct or I am not knowing how to do so?

2

Depending on the services you use, a service account accessing Unity’s API’s might be what you are looking for: Admin authentication | Unity Services Web API docs

3

Yeah, I reached to this documentation, however in economy part, we can only change settings of the Economy, for example the currencies, but I didn’t find anything about changing player’s currency balance for example.

4

Hi,

It is doable, but it is medium difficulty.
Honestly, it’ll be much easier if you use CloudCode for that use-case, that’s what it was designed for.

However, for completeness, I’ll elaborate how to do it with the custom server.:

Short Version: The cloud-code package has npm packages of the services’ api’s for local authoring.
You can basically pull those into your own node.js server and use them from there. You will need to authenticate on your own.
Example of where to find npm packges: \Library\PackageCache\com.unity.services.cloudcode@2.6.2\UnityServicesNpmLocal~

The API is also explained here: Unity Services Web API docs

You can either use the npm’s above, or generate from the Open API specification.
Here’s an example js script through cloud code. You will be writing very similar code.

You DONT need to use cloudcode, it just happens to be in JS so it helps your case. Your life would be a lot easier if you did, since they already integrate out of the box since with CloudCode though, you already have player and trusted authentication.

Long version:
I noticed you talking about admin APIs and auth. Let me clarify some of that.
We’re mixing 2 intersecting things here.
APIS: Admin API / Client API
Authentication: Admin auth, Client Auth, Server Auth*

Client APIs are the ones that change player state (like a game client / game binary would)
Admin APIs are the ones that change service settings (like you would through the dashboard / deployment window)

Player authentication is how the game client authenticates, so that a player CANNOT change different player’s state or admin settings.

Admin authentication can change admin settings AND can change ANY player state (since its an admin operation)

             | Admin Auth    | Client Auth
Admin API    |  Dashboard    |  Impossible
Client API   |   "Trusted"   | Game Client

*Server auth: when running a Multiplay server or CloudCode

The main issue you’ll face is getting authenticated, you could pass the token from the game client to your custom server, or create a service account token like in the documentation you linked.

Granted it is doable, but isnt easy, it is not a use-case we have focused on, as we look more at the Unity server and CloudCode options.

If you were using a different dedicated server (like Python or C++), would be doable but harder still, as you don’t even have a package, you’d need to generate one from the OpenAPI specs.

Hope it helps,

Cheers,

Gab

5

Well Gab, Thank you for your time.

Yeah, the main issue I’m facing is the authentication, because the endpoint that I’m trying to use which is https://services.docs.unity.com/economy/v2/index.html#tag/Currencies/operation/setPlayerCurrencyBalance, needs a player authentication token, and as my server doesn’t have one, it fails.
I believe that sending the players token by the Req to the server would solve.

However I would like to ask you, if I keep these codes in the game, in other words, in the client side, it would be safe because it’s a Unity SDK or something? Or it still has security issues?
Because I am changing my currency “by myself”, in the client side, could a cheater insert any data on those SDK’s methods?

6

Hi LMatias,

Auth is harder but still doable. You should be able to use service account token, you dont necessarily need player auth. (this seems misdocumented in the economy API)

This is how we do it in the CLI C# side:

    internal static string CreateToken(string serviceKey, string serviceSecret)
    {
        var decodedToken = $"{serviceKey}:{serviceSecret}";
        var token = Convert.ToBase64String(Encoding.UTF8.GetBytes(decodedToken));
        return token;
    }

The final “Authorization” header should be “Basic ”

If a hacker changes the code, yes they can give themselves currency or items.
That’s where cloud-code comes in, it allows you to write server code easily that ensures that it remains server authoritative.

Is using CloudCode an option for you? If so, I recommend it. You can upgrade to your own service later in any case.

You may also want to look at Access control, which prevents more sophisticated hackers from poking the endpoints.

Let me know if you have any more questions.

Cheers!