how the iphone apps keep user logged in - iphone

A lot of apps keep user logged in until user manually logs out like facebook, dropbox, etc.
I am wondering how they achieve it? There might be several approaches:
1)Do they store the username and password in a local storage, and automatically log the user in when they open the app again after a long time?
2)Or do they get a long-lived token from the server, and once the user login at very first time, the app gets a token from the server, later on they just use the token? The token will be valid until user manually logout from the app.
For #1, it will only work for native login, if an app supports "log in with facebook or twitter" it won't work.
So I just want to get an idea about how people achieve this feature? Is there any articles talk about it?

Most services like Facebook and Twitter use OAuth to manage the user session.
I use this external framework... https://github.com/nxtbgthng/OAuth2Client
It took me a while of reading and setting up to get right but it works now.
When the user logs in they get an auth token that contains an expiry date. When the expiry date comes the system automatically refreshes the token.
When I send a request to the server I send it via the OAuth framework and it adds the authorisation automatically.

Related

Setup for Login with Facebook and my own OAuth. Usage of Facebook tokens

I need to setup communication between my iOS/Android app and my PHP backend. I want to use facebook account only for logging in, there is no further communication with facebook. I have User accounts in my system and facebook_id is only a parameter to identify user.
Is it ok to verify the user by checking the token on the graph api from my backend just at the beginning and then only use my own tokens for communication or do I need to recheck if the user is still logged in on facebook from time to time (which is actually irrelewant for me as there are no fb interactions).
What else is there to consider?
Do I need a separate token for my server? Or do I use my App Secret
You should be able to use your application token.
The only scenario it might not work in is if the user deletes your app and decides to login again. From what I've read the app scoped IDs may change in this scenario.

xamarin Auth for facebook authentication scenarios

I am developing an application using xamarin.Here I am using xamarin auth component for facebook authentication.I am able to login and get users info and able to save them in local DB.Xamarin auth component has provided option for storing account object so that when user relaunch app ,we can use that account object to login.
Here comes my question: If user changes password on facebook account from site then what should be done when app is relaunching,as stored account is local we can't use that info to login again.
Thanks.
Any suggestions are appreciated.
Actually you are supposed to use the access_token for subsequent queries towards Facebook after the first successful authentication. With OAuth, you won't store password in your app. I would expect that when a user changes the password within Facebook, the old access_token might expire. In this case, you'll have to make the user manually re-login. This is the case anyhow when your access_token expires for any reason; keep in mind that all access_tokens expire after some time.
You can easily verify if the access_token is still valid by sending some basic request in the background. If you get an autherror response, just prompt the user to login again when it makes sense in the flow of your app.

Facebook Access-Token for Server Side

I'm trying to create a server side access to a user's Facebook resources (photos/albums/etc).
I want that the user will authenticate once using its native mobile application, and that the server will be able to access user's data without the user interaction.
I'm trying to understand the steps I need to take in order to make it work.
I've read Facebook's: Login for Server-side Apps but I can't understand how to use the scenario proposed in there - because my server has nothing to do with user interaction (I cannot redirect the user to some login dialog) - the server is performing its own operation in the background whether the user is using its mobile application or not. What should I do upon token expiration for example?
More then that, I want that the user will be able to perform direct Facebook operation on the mobile itself, without the server intervention.
As I see it, this is the flow I would expect:
User's launches a native mobile application.
The user authenticates using Facebook's SDK on the native mobile app.
The user received a special token, that can be converted at server side to an access-token.
The token will be sent to the server and stored there.
If the server needs to access user's Facebook data, it uses this special token and converts it to an access token.
When the token expires - the server can extend it, using the special token, without any user interaction.
What data should be sent to the server from the mobile application after authentication. And how should the server use this data to access user's Facebook resources anytime?
I'm using the C# Facebook SDK for the server. But I think it is not that important, I need to understand the mechanics.
Tokens expire if the user does not continue to use the application. This is by design--an application should not continue to access the user's account if the user stops using the application.
When a user logs into your application, a token is given to your application, along with an expiration date for that token. You can use that token from your client or your server until it expires. However, there is nothing your server can do to extend the token if the user does not continue to use your application.
If the user continues to use your application, you will have an opportunity to update your server token. For example, in the Android and iOS SDKs, tokens are automatically refreshed if the user uses your application to make a facebook request. At that time, you can transmit the refreshed token to your server.

How to notify users peridocally from an app

So there's an app, let's say it's an app that is capable of delivering relevant news based on the user's choice done the first time he runs the app. Is there a way to post the news to the user's wall without having the user to be online and ideally as the app?
So on his/hers timeline it would look like this (edited image, not a real post from some app, it's just so you get what I mean):
When I use $facebook->api('/me', 'post'), it just creates a post as the user, which is not what I want and does not allow me to post when the user is not logged in.
You can use the server side authentication to get a long lived access token (60 days) which you can then use until the token times out. Then you'll need to have the user reengage with your app to get a new token.
You can get the same thing by using the client side authentication and then extending the token on the server side.
Another options which should work for you is to get an app access token (which does not expire) and ask the user for the publish_stream permission, then:
App access tokens can also be used to publish content to Facebook on
behalf of a user who has granted a publishing permission to your
application.

How can I avoid asking users to login (connect) to my facebook app again and again?

I am developing and testing a facebook app for which I have granted the permissions with my facebook account. Then the app is authorized to access my info, etc. nicely. The next time I close the browser, reopen it, login to facebook successfully then access the app, facebook wants me to login to that app again. I can access the current user id, but how can I automatically authorize the app (if the user has already authorized in the past) without needing the user to press that dread 'Login' button again and again upon each session's end?
UPDATE - offline_access has been deprecated. Read this post for more details: https://developers.facebook.com/roadmap/offline-access-removal/
You will need to request a token that has offline_access so that you can use their authentication token over and over again. Then you will need to set a cookie yourself that stores something indicating who the user is. Facebook does not support a "remember me" feature in their authentication so you have to build it yourself. Store the access token in your database and set the cookie to identify the user.
Unless you are building this for a very specific reason like an app that runs on work computers only, I would really encourage you to not implement this feature. The facebook connect authorization is well understood by users and is very easy to use. You are going to get a lot more security if you make your users press the button every time. Just make sure you make this optional. You never know if somebody is on a public computer.