Backend Implementation of Apple's DeviceCheck and Google's SafetyNet Attestation API

DeviceCheckCoordinator.ts

import BaseService from "./BaseService";
import BaseCoordinator from "./BaseCoordinator";
import { DeviceCheckParams, DeviceCheckService } from "./DeviceCheckService";
import { GoogleSafetyNetAttestationService } from "./GoogleSafetyNetAttestationService";
import { AppleDeviceCheckService } from "./AppleDeviceCheckService";
import * as UserAgentParser from "../helper/UserAgentParser";


export default class DeviceCheckCoordinator extends BaseCoordinator {

    private loggingTag = "DeviceAuthenticityCheck";

    public async shouldProceed(userAgent: string, token: string | undefined, timestamp: number, binding: string): Promise<boolean> {

        if (!token) {
            this.logger.warn(`${this.loggingTag}: ${userAgent}: no token given`);
            return false;
        }

        let deviceCheckService: BaseService & DeviceCheckService | undefined;
        const deviceCheckParams: DeviceCheckParams = {
            timestamp,
            token,
            binding,
        };

        if (UserAgentParser.os(userAgent) === "iOS") {
            deviceCheckService = new AppleDeviceCheckService();
        } else if (UserAgentParser.os(userAgent) === "Android") {
            deviceCheckService = new GoogleSafetyNetAttestationService();
        } else {
            this.logger.warn(`${this.loggingTag}: ${userAgent}: invalid user agent`);
            // cannot be the case for valid clients => do not proceed
            return false;
        }

        if (deviceCheckService && deviceCheckParams) {
            try {
                const isDeviceAllowedToProceed = await deviceCheckService.shouldProceed(deviceCheckParams);
                if (isDeviceAllowedToProceed) {
                    this.logger.info(`${this.loggingTag}: ${userAgent}: device authenticated`);
                    return true;
                } else {
                    this.logger.warn(`${this.loggingTag}: ${userAgent}: suspicious behavior detected`);
                    return false;
                }
            } catch (error) {
                this.logger.error(`${this.loggingTag}: ${userAgent}: device check skipped due to error: ${error}`);
                // external errors force us to skip check => proceed
                // otherwise Apple/Google failures can block our services
                return true;
            }
        }

        return false;
    }

}

Where is AppleDeviceCheckService? :)