Is it appropriate to check user auth to server api in every activity (i assume using base activity on resume)? It is to prevent user login on multiple device with same account. Or is there better approach for this?
There is several approach to handle this.
Push notification - When same user login in another device then you need to send push notification to first login device. When first login device get notification then you can put your logic there.
Put Logout status on every api - You need to check logout status code in every api response. When you get logout status code then you can put your logic there.
Note: For second approach you need to make one generic api calling class. So, You don't need to put this status code in every api calling code.
So I'm assuming that every successful sign-in then the server gives you back a unique auth-token which should invalidate any previously assigned token.
My approach is usually just to allow the user to continue using the app with whatever cached data that's already there until I hit a scenario that needs to do an API call. And if I get an error code like HTTP 401 or 403 because the auth token was invalidated then should send me back to the sign-in screen.
Doing an explicit API call in onResume() seems wasteful and is basically client-side polling I would only do this if it was a very strict requirement to keep the auth information fresh because the information on screen is sensitive.
Related
My app sends notifications using Firebase Cloud Messaging FCM. For every user, I'm storing the device token in database and I fetch it when I want to notify him. I'm using FirebaseMessagingService with the overridden method onNewToken that updates my database with new tokens. I suppose that this method is called every 1 hour to check token's update, but I was expecting it to be also called when the service is initialized for the first time (after installing and running the app on device). However this is not the case. To remedy this, I could call onNewToken each time the user log in But I would like to know if this is an acceptable way or there is a better one.
To avoid abuse, I leave here extra information on my case :
I run my app on Android Studio emulator and I check the stored token in database, let's call it TOKEN-1.
Now I install the app on my phone and I show the token with String token = FirebaseInstanceId.getInstance().getToken(); Toast.makeText(MainActivity.this, token, Toast.LENGTH_LONG).show();
The token is different that the first one TOKEN-1, and TOKEN-1 is still stored in my database. This means that I can receive notifications only on emulator and not my phone.
Sorry for my long text and looking forward to reading your suggestions.
The FCM SDK and server work together to manage the token in the background, and listening to onNewToken ensures that you get notified when the token changes. For this reason you should always be listening to onNewToken, and update it in your own database whenever it changes.
There is no guarantee that your FCM token will be refreshed every hour (or even ever) though, as you seem to expect. Given the 1 hour interval, you might be thinking of Firebase Authentication ID tokens, which are short-lived and are indeed refreshed every hour.
Finally: the token doesn't get refreshed when you attach a listener. In fact: if the token was already generated before you attach a listener, your listener won't be called. For this reason, you'll typically also want to grab the current token in your main activity when the app starts, and store it in the database at that point.
This last code is mostly necessary during development, as that's where you're most likely to have the scenario where the token gets generated when you don't have an onNewToken listener yet. So instead of putting code in the main activity, you can also uninstall/reinstall the app after adding your onNewToken listener, as FCM will generate a new token upon installing the app in that case - and thus call your onNewToken with this initial token.
I have a REST API secured with JWT. The client is an Android app and a web app. Android app gets a new token when a user login, after that it works with that token. However the token will expire in 60 minutes, so I have to refresh it. I know there are 3 approaches for this.
issue a fresh token in every request
issue a fresh token when the current one is close to expire. e.g. 10
min
let client app request a new token when it needs it using a "refresh
service" of your api.
Please consider the following...
I am not happy about the first suggestion above
I did try the third suggestion. However in my android app I got like 60 REST calls. Then what I should be doing is with every REST call (ex: getUsers()), I first have to check whether the token is about to expire and if yes, get a new token from REST API (That means I have to run another REST call to the refresh() method in API). After this check and getting the new token I can execute the getUsers() method. The problem here is that every REST call should run inside the onResponse() method of my refresh() method (I am using Retrofit) and that is simply not possible as I have to then duplicate the same method for 60 times with 60 names. I am sure the same issue will arise with the web app as well.
Due to the above reasons I am considering the 2nd suggestions in my first list, renewing the token at the server it self. If the token is "valid" and if it is "about to expire" I will refresh it from server and will send to app as a header.
I need to know whether that method is an industry practicing method and whather it is the best choice. If not, how I can proceed with the 3rd suggestion in my first list.
I have recently implemented the similar setup with JWT in one of my Android apps. I don't know if my suggestion will help you, but it might give you an insight on how others are doing it.
Option 1: This is very much redundant, and it violates the sole purpose of using JWT in the first place. If I get a new JWT on every request, I can use that for further requests, thus practically have a token with no expiration.
Option 2: This requires server side extra operation, plus this is not feasible. How do you plan to detect which tokens are already distributed and "about to expire" so that you can renew them? Tons of users will have tons of tokens and if you plan to save JWT in database, then it would get too messy.
Option 3: This method is too redudndant and requires client side operation on checking whether token is about to expire and calling refresh service based on that. I always prefer lesser operation to do more work.
What I did, is that, I used two tokens for the system. One as a Refresh Token (token used to request JWT refresh) and one as JWT (for every request validation).
With successful login, received a refresh token and saved it locally in app (SharedPref). This token is also preserved in database too. Next, requested and validated JWT with that with that refresh token. From now onwards, every request contains this JWT in header. I also request new JWT everytime when my app is opened, i.e, in my Splash page.
Now, if any request contains expired JWT, simply return a common response like "Session expired" with a fixed status code. If any HTTP request has this specific status code in its response, I requested another API call with the refresh token to get fresh JWT for future requests.
As I needed to add this check (whether contains "Session Expired") in every HTTP response, I wrote a common function and passed the HTTP responses via that method, so that, I do not need to rewrite or copy-paste every bit of it.
This requires very less code and minimal operation on both server and app end. My system has a JWT expiration time of 20 minutes and I haven't faced any problem till now. Worst what happens is, in a single request, user receives token expired, gets token, and recalls that function. This results in a slightly delayed operation for users that is already in my app continuously for more than 20 minutes. If any user is in my app for that long, it's a good problem to have, right? :)
It's not clear whether the users have to log-in in your app every time or session is held so that logged-in users can directly enter the app. If session is hold, just keep the refreshToken in app locally (SharedPref) and use that to get JWT every time the app is opened. If any user is misusing your API (scraping or for any other purpose), simply move that specific refresh token to a black-list so that this user doesn't get new JWT.
Please let me know if anything's not clear. Thanks.
I would like to manage Login/registration between android app and a server (php+mysql). I'm looking for a solution which allow the user to login just one time and then, since the session is valid, stay logged even if He will close the app and open it again. Something similar to facebook and google login. I read something about OAuth2 and It seems to do what I'm looking for but I'm not able to find a good tutorial for php(server)/android part. Any suggestion? thank you in advance.
Two important things need to implement for your requirement i.e.
1) Login success flag stored to sharedPreferences
2) Token Validation
write a php api to validate login user and return the success flag i.e. valid login or not. On mobile side - if successful login triggers then store the success flag at sharedPrefernces
Token validation - when user successfully logins to the system then php api returns the login success flag with unique token and last access date and time everytime when it hits to login service.
every time when you are hitting to any php api you have to pass the token and lastaccessdate to php api. php api validates it by token matching and lastaccessdate with currect server date and perform an minus operation between them. if you want to keep login validate for 7 days to validate according to it.
Save your status in shared preferences or SQite database
I'm using anonymous users with parse but user ID keeps changing every time the app is restarted. I can create a serious of records, tied to a user and see them in backend / the app itself. Then kill the app, restart it and see a new user in Parse backend. Obviously, all records are no longer displayed because this is a "new user".
How can I make anonymous user id persist?
Turns out, if you're using Parse SDK and their anonymous users, you need to check if user is logged in and then run anonymous user initialization only in that case. Otherwise, each time the app is restarted, a new anonymous user is created. Makes sense but wasn't in their docs.
When you 'create' a new user, i think that you are getting an implied 'logon' of that new user.
Note that the response to the logon includes a session token ( no expiration on token ).
Using 'sharedPreferences' or some other android persistence technique, when you restart the app you can just retrieve the token from your persistence layer and - at least in REST API - just include that token in your headers along with AppId, and REST key and you will get that users data.
If you are using the SDK and not rest api, there may be some other way to get back to a reference for the user.
I am using Parse API for my app and I am going to be using the ParseUser object to maintain a user database. At the beginning, the user will be logged in using the logInInBackground() method.
Now, say that the connection is slow and the login is taking time or as soon as the user hits the sign up / sign in button, he gets a call and the activity is suspended. The call can go on for a long time (if the user is a blabber mouth) while the login/signup process continues in the background.
If it is successful, a new Activity is to be started or if it fails, an error message is to be displayed. However, since the Activity is suspended, how do I deal with it?
Do I keep some booleans, update SharedPreferences or what?
I know that in onPause() and onStop() background tasks have to be stopped.
Reference: https://www.parse.com/docs/android/api/?com/parse/ParseObject.html
Take a look at the User logon section of Rest API docs.
It walks u thru the process of submit a logon that sends a TOKEN in the response.
Note that at parse.com that token NEVER expires.
One usage on the client with a perpetual lease on the token is that you only have to log one time on one client. After that, assuming you do not need to switch among users, the SharedPreference persistence layer can keep the parse user token value for when its needed.
No logon step is necessary because any subsequent parse request can be accompany by the token.
I always use REST api. IMO parse only needs the token and not something like a user session.