Integrating mobile compatibility into an existing Linux-based open-source library using Flutter
I'm working on a personal project and I can't seem to get I recently switched to Quick question that's been bugging me - I'm stuck on something that should probably be simple. Recently started working with an open-source project that utilizes a Linux-based backend, and I need to add mobile compatibility to it using Flutter. The library serves as an API that interacts with various microservices, and I want to ensure that mobile clients can efficiently communicate with it. Currently, I've set up a Flutter app that successfully communicates with the backend, but I'm facing challenges with handling authentication across mobile devices. The existing backend uses JWT for authentication, and I must ensure that the token is correctly issued and validated on mobile. I've implemented the following Dart code in my mobile app to handle the login process: ```dart Future<void> login(String username, String password) async { final response = await http.post( Uri.parse('https://myapi.com/login'), body: json.encode({ 'username': username, 'password': password, }), headers: { 'Content-Type': 'application/json' }, ); if (response.statusCode == 200) { final Map<String, dynamic> responseData = json.decode(response.body); storeToken(responseData['token']); // Placeholder function to store JWT } else { throw Exception('Failed to log in'); } } ``` This code works well in a local environment, but I've noticed that when I deploy it on different mobile devices, the API responses sometimes lag or fail to return the expected JWT, resulting in a 401 unauthorized error. As part of my investigation, I set up logging in the backend to track incoming requests. It appears that the requests from mobile devices are sometimes missing the `Authorization` header that should contain the bearer token. To ensure this is not a client-side issue, I added detailed logging on the Flutter side. I used the `http_interceptor` package to log requests and responses. Still, the issue persists intermittently, especially on slower networks. I've also tried enabling CORS in the backend by adding the following snippet to my Flask application: ```python from flask_cors import CORS app = Flask(__name__) CORS(app, resources={r'/api/*': {'origins': '*'}}) ``` This change seemed to alleviate some issues, but not all. My next step is to implement retries on failed requests in my Flutter app, but I'm unsure how often to retry without overwhelming the server. Would it be better to use exponential backoff? Any insights or suggestions on how to resolve the authentication issues and improve mobile compatibility would be greatly appreciated. Lastly, any best practices for managing state in Flutter when dealing with JWTs and session management would also be helpful. Thanks in advance! For context: I'm using Dart on macOS. I'd really appreciate any guidance on this. I've been using Dart for about a year now. Thanks for taking the time to read this! Cheers for any assistance!