How to make user disconnect at RegisterBeforeAuthenticateXXXX

Local Setup
1

Hello everyone, I have a problem, If i want to kick user at “RegisterBeforeAuthenticateEmail” this checkpoint, How to make user disconnect?

2

I assume by “kick” you are actually referring to disallowing the user to authenticate with the system.

According to the documentation from this page:

If you choose to return nil instead of the payload (or a non-nil error in Go) the server will halt further processing of that message. This can be a used to stop the server from accepting certain messages or disabling/blacklisting certain server features.

This is quite simple and can be done with a few lines of Lua/Go:

local nk = require("nakama")

local M = {}

function M.authenticate_email(context, payload)
  local email = payload.account.email
  -- local password = payload.account.password

  -- perform custom logic here
  if (email == "pineapple@pizza.com") then
    return nil
  end

  -- make sure that you return payload
  return payload
end
nk.register_req_before(M.authenticate_email, "AuthenticateEmail")

return M
3

thanks your answer.

4

Hi @mofirouz, May I ask you more questions about this case?
The thing is I can disconnect use by return nil, errors.New(“error”) in the server. However, the user client can’t detect this message. I mean I can’t catch any exception in the client, it just awaits forever.
Here is my unity client code

try
						{
							session = await client.AuthenticateDeviceAsync(deviceId, deviceId);
							PlayerPrefs.SetString(RefreshTokenKey, session.RefreshToken);
						}
						catch (ApiResponseException ex)
						{
							Debug.LogFormat("Error: {0}", ex.Message);
						}
						catch (Exception e2)
						{
							Debug.LogError(e2.ToString());
						}
5

Ok firstly, the word “disconnect” is misleading - you are not connected to a socket to be disconnected from the said socket.

Secondly, please post your Go code, as I suspect you have an issue there; have a look at this for guidance:

6

Here is my go code:

func BeforeAuthenticateDevice(ctx context.Context, logger runtime.Logger, db *sql.DB, nk runtime.NakamaModule, in *api.AuthenticateDeviceRequest) (*api.AuthenticateDeviceRequest, error) {
	 logger.warn("beforeauthenticatedevice:" + in.account.id + " " + in.username + " deviceid: " + in.account.id)
	 if len(in.account.id) != 32 || strings.index(in.account.id, "somefixedkey") != 0 {
	 	logger.warn("cannot authenticate your token")
	 	return nil, errors.new("cannot authenticate your token")
	 }
	return in, nil
}
7

You need to return a particular type of error in your Go code that follows this:

Your code should be:

func BeforeAuthenticateDevice(ctx context.Context, logger runtime.Logger, db *sql.DB, nk runtime.NakamaModule, in *api.AuthenticateDeviceRequest) (*api.AuthenticateDeviceRequest, error) {

//....

return nil, nk.NewError("cannot authenticate your token", 13) // Internal Code = 13, which returns a HTTP 500.
}
8

I’m sorry because nk has no NewError function but the runtime does.
So, I tried as follows:
return nil, runtime.NewError("Invalid token, please login again", 13)
but the client still cannot catch the exception

9

How are you registering your BeforeHook? Can you show me that too plz?

10

Thank you for your reply,
Of course, I registered and I also check it by putting some logs to the AuthenticateDevice function too.

initializer.RegisterBeforeAuthenticateDevice(BeforeAuthenticateDevice)