Custom Authentication for Itch.io #

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func InitModule(ctx context.Context, logger runtime.Logger, db *sql.DB, nk runtime.NakamaModule, initializer runtime.Initializer) error {
		// Register BeforeAuthenticateCustom Hook to authenticate against Itch.io.
		initializer.RegisterBeforeAuthenticateCustom(BeforeAuthenticateCustom)

		return nil
}

func BeforeAuthenticateCustom(ctx context.Context, logger runtime.Logger, db *sql.DB, nk runtime.NakamaModule, in *api.AuthenticateCustomRequest) (*api.AuthenticateCustomRequest, error) {
		token := in.GetAccount().GetId()
		logger.Debug("Attempting to login with Itch.io using Token: %v", token)

		if token == "" {
				return in, runtime.NewError("Missing Itch.io token.", 3) // gRPC status code 3 - INVALID_ARGUMENT
		}

		client := &http.Client{}

		const itchURL = "https://itch.io/api/1/jwt/me"
		req, err := http.NewRequest("GET", itchURL, nil)
		if err != nil {
				return in, runtime.NewError(fmt.Sprintf("Error creating network request object: %v", err), 14) // gRPC status code 14 - UNAVAILABLE
		}

		req.Header.Add("Authorization", "Bearer "+token)

		resp, err := client.Do(req)
		if err != nil {
				return in, runtime.NewError(fmt.Sprintf("Network request failed: %v", err), 13) // gRPC status code 13 = INTERNAL
		}

		if resp.StatusCode >= 300 {
				return in, runtime.NewError(fmt.Sprintf("Itch.io authorization request error: %v", resp.Status), 16) // gRPC status code 16 = UNATHENTICATED
		}

		body, err := ioutil.ReadAll(resp.Body)
		if err != nil {
			return in, runtime.NewError(fmt.Sprintf("iotil.ReadAll failed: %v", err), 13) // gRPC status code 13 = INTERNAL
		}

		var response struct {
				User *struct {
					Username    string
						DisplayName string `json:"display_name"`
						ID          int
				}
				Errors []string
		}

		if err := json.Unmarshal(body, &response); err != nil {
				return in, runtime.NewError(fmt.Sprintf("Failed to unmarsdhal Itch.io response: %v", response.Errors), 13)
		}

		if len(response.Errors) > 0 {
				return in, runtime.NewError(fmt.Sprintf("Itch.io response has errors: %v", response.Errors), 13)
		}

		// Add a prefix to ensure ID is >= 6 characters as Itch.io IDs may be shorter.
		in.Account.Id = fmt.Sprintf("itch-%d", response.User.ID)

		// If no username was passed, take the username from Itch.io.
		if in.Username == "" {
				in.Username = response.User.Username
		}

		return in, nil
}