Facebook login authentication - facebook

Currently I have a option in my web page such that, on-clicking a button, Facebook login authentication dialog will be poped up as explained in http://developers.facebook.com/docs/authentication/#server-side-flow. I am using JavaScript SDK (FB.api) for this.
So on users successful authentication and app authorization, I will retrieve an ACCESS TOKEN for that particular user from the response. To avoid token expiration, I am using OFFLINE_ACCESS. Finally the token is saved in my local database and a cron job will use this token periodically to read users Facebook datas.
My problem is, as Facebook is going to deprecate the offline_access, is there any other way to have unique ACCESS TOKEN for a user (with out expiration time), such that the users will approve my app once and the cron job will use their token to read data on regular basis.
From this link: http://developers.facebook.com/roadmap/offline-access-removal I found that we can only extend the token expiration time.
Can anyone please suggest a solution for this?

Related

Facebook Token Renewal

My team have developed an App, in which we are using the Facebook Authentication Tokens to retrieve the data from a Facebook and then display it on our App and it is working fine.
The problem which I am facing is that if the Password of Facebook Account is changed then the API Token also become useless, which is an obvious thing.
But is it possible that when a user updates his/her Facebook Account Credentials then the API Token also gets updated? i.e. I don't want to go through the Token Generation Process, every time the password is changed.
No, that is not possible.
When the user changes their password, all their existing tokens get invalidated on purpose.
They will have to go through the login flow again, to create a new token.

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.

Is this process correct for maintaining long-lived Facebook Access Tokens when the user may not have access to the FB account?

I am creating a system to allow our clients to create articles and post them in our CMS. The one feature we are being asked to implement is that when an editor publishes an article, that that article gets posted to the company's facebook wall as well.
The tricky part to this is that the people who are allowed to publish articles may not have login credentials to the company's overall FB account. This means that I can't rely on the normal process to retrieve access tokens for accounts (or so it seems).
I did quite a bit of research and came up with the following documentation sources:
http://developers.facebook.com/docs/howtos/login/extending-tokens/
http://developers.facebook.com/docs/howtos/login/server-side-login/
http://developers.facebook.com/docs/concepts/login/login-architecture/
http://developers.facebook.com/roadmap/offline-access-removal/
From these it seems that in order to allow locally authorized users to post to the company's facebook wall I must:
Have a user with valid FB credentials log into an Admin page
Click a button to start the authorization process
Retrieve the short term access token from the FB response and exchange it for a long-lived 60 day token
Store the 60 day token in our database
Each time a user attempts to publish an article, test if the token has expired and if so alert the admin they need to re-authorize.
Is this the only workflow to accomplish this or is there a simpler method, preferably one that does not require the last step.
Use a page token. Get it using a long-lived user access token – then the page token will not expire by default.

Posting to Facebook on behalf of the user: how to handle token expiration?

I'm implementing a connect with Facebook/Twitter/... functionality on a website. The idea is that once a user connects his account with the external services our website could post messages on behalf of the user.
With Twitter there is no problem as the OAuth access_token doesn't expire. But with FB it does expire every two months, when the user logouts, changes password or explictly deauthorizes the app.
How should I handle the token expiration? For me it would be ideal if I could refresh the token automatically without bothering the user, but unless I've missed something it seems there isn't any way of doing this. So, right now I've two ideas:
The less akward way: every time the user logins to the website check if the tokens have expired and notify the user that she has too reauthorize the app.
The more akward way: every time the "post to social networks" event triggers in our website, check if the tokens have expired and ask the user to reauthorize.
The first option would be easier to implement and cleaner to the user.
So, how are you handling this situations?
Thanks!
I think that I'll trye the first option:
User logs in
The server checks if the user has already a Facebook token, if so:
Check if it's still a valid token. http://developers.facebook.com/docs/howtos/login/debugging-access-tokens/
If the token expired NOT because the user deauthorized the app BUT because the other cases we redirect the user to the OAuth endpoint.
I'll give it a try and update this answer if there is more to it.
If the user is actually interacting with your website, you should be getting a fresh access_token (read below). If you perform offline tasks related to the user using the Facebook API then you should be storing the access_token and their expiry dates. Then you need to handle expired access tokens and ask the user to interact with your app again and update your records.
You should refer to this document. Also you should be reading the Extending Access Tokens document:
Step 2. Refreshing Long-lived User Access Tokens
At any point, you can generate a new long-lived token by repeating the
original auth flow, obtaining a new short-lived token and then
performing the same exchange as above. In some cases, this newer
long-lived token can be identical to the previous one, but we do not
guarantee this will be true and your app shouldn't depend upon it.

Do Facebook Oauth 2.0 Access Tokens Expire?

I am playing around with the Oauth 2.0 authorization in Facebook and was wondering if the access tokens Facebook passes out ever expire. If so, is there a way to request a long-life access token?
After digging around a bit, i found this. It seems to be the answer:
Updated (11/April/2018)
The token will expire after about 60 days.
The token will be refreshed once per day, for up to 90 days, when the person using your app makes a request to Facebook's servers.
All access tokens need to be renewed every 90 days with the consent of the person using your app.
Facebook change announce (10/04/2018)
Facebook updated token expiration page (10/04/2018)
offline_access:
Enables your application to perform authorized requests on behalf of the user at any time. By default, most access tokens expire after a short time period to ensure applications only make requests on behalf of the user when the are actively using the application. This permission makes the access token returned by our OAuth endpoint long-lived.
Its a permission value requested.
http://developers.facebook.com/docs/authentication/permissions
UPDATE
offline_access permission has been removed a while ago.
https://developers.facebook.com/docs/roadmap/completed-changes/offline-access-removal/
Try this may be it will help full for you
https://graph.facebook.com/oauth/authorize?
client_id=127605460617602&
scope=offline_access,read_stream,user_photos,user_videos,publish_stream&
redirect_uri=http://www.example.com/
To get lifetime Access Token you have to use scope=offline_access
Meaning of scope=offline_access is that :-
Enables your application to perform authorized requests on behalf of
the user at any time. By default, most access tokens expire after a
short time period to ensure applications only make requests on behalf
of the user when the are actively using the application. This
permission makes the access token returned by our OAuth endpoint
long-lived.
But according to facebook future upgradation the offline_acees functionality will be deprecated for forever from the 3rd October, 2012.
and the user will be given 60 days long-lived access token and before expiration of the access token Facebook will notify or you can get your custom notification functionality fetching the expiration value from the Facebook Api..
Note that Facebook is now deprecating the offline_access permission in favor of tokens for which you can request an "upgrade" to the expiry. I'm just now dealing with this, myself, so I don't have much more to say, but this doc may help:
https://developers.facebook.com/docs/offline-access-deprecation/
I came here with the same question as the OP, but the answers suggesting the use of offline_access are raising red flags for me.
Security-wise, getting offline access to a user's Facebook account is qualitatively different and far more powerful than just using Facebook for single sign on, and should not be used lightly (unless you really need it). When a user grants this permission, "the application" can examine the user's account from anywhere at any time. I put "the application" in quotes because it's actually any tool that has the credentials -- you could script up a whole suite of tools that have nothing to do with the web server that can access whatever info the user has agreed to share to those credentials.
I would not use this feature to work around a short token lifetime; that's not its intended purpose. Indeed, token lifetime itself is a security feature. I'm still looking for details about the proper usage of these tokens (Can I persist them? How do/should I secure them? Does Facebook embed the OAuth 2.0 "refresh token" inside the main one? If not, where is it and/or how do I refresh?), but I'm pretty sure offline_access isn't the right way.
Yes, they do expire. There is an 'expires' value that is passed along with the 'access_token', and from what I can tell it's about 2 hours. I've been searching, but I don't see a way to request a longer expiration time.
since i had the same problem - see the excellent post on this topic from ben biddington, who clarified all this issues with the wrong token and the right type to send for the requests.
http://benbiddington.wordpress.com/2010/04/23/facebook-graph-api-getting-access-tokens/
You can always refresh the user's access token every time the user logs into your site through facebook.
The offline access can't guarantee you get a life-long time access token, the access token changes whenever the user revoke you application access or the user changes his/her password.
Quoted from facebook http://developers.facebook.com/docs/authentication/
Note: If the application has not requested offline_access permission, the access token is time-bounded. Time-bounded access token also get invalidated when the user logs out of Facebook. If the application has obtained offline_access permission from the user, the access token does not have an expiry. However it gets invalidated whenever the user changes his/her password.
Assume you store the user's facebook uid and access token in a users table in your database,every time the user clicks on the "Login with facebook" button, you check the login statususing facebook Javascript API, and then examine the connection status from the response,if the user has connected to your site, you can then update the access token in the table.
Hit this to exchange a short living access token for a long living/non expiring(pages) one:
https://graph.facebook.com/oauth/access_token?
client_id=APP_ID&
client_secret=APP_SECRET&
grant_type=fb_exchange_token&
fb_exchange_token=EXISTING_ACCESS_TOKEN
log into facebook account and edit your application settings(account -> application setting ->additional permission of the application which use your account). uncheck the permission (Access my data when I'm not using the application(offline_access)). Then face will book issue a new token when you log in to the application.
Basic the facebook token expires about in a hour. But you can using 'exchange' token to get a long-lived token
https://developers.facebook.com/docs/facebook-login/access-tokens
GET /oauth/access_token?
grant_type=fb_exchange_token&
client_id={app-id}&
client_secret={app-secret}&
fb_exchange_token={short-lived-token}
This is a fair few years later, but the Facebook Graph API Explorer now has a little info symbol next to the access token that allows you to access the access token tool app, and extend the API token for a couple of months. Might be helpful during development.
check the following things when you interact with facebook graph api.
1) Application connect URL should be the base of your "redirect_uri"
connect URL:- www.x-minds.org/fb/connect/
redirect_uri - www.x-minds.org/fb/connect/redirect
2) Your "redirect_uri" should be same in the both case (when you request for a verification code and request for an access_token)
redirect_uri - www.x-minds.org/fb/connect/redirect
3) you should encode the the argument when you request for an access_token
4) shouldn't pass the argument (type=client_cred) when you request for an access_token. the authorization server will issue a token without session part. we can't use this token with "me" alias in graph api. This token will have length of (40) but a token with session part will have a length of(81).
An access token without session part will work with some cases
eg: -https://graph.facebook.com/?access_token=116122545078207|EyWJJYqrdgQgV1bfueck320z7MM.
But Graph API with "me" alias will work with only token with session part.
I don't know when exactly the tokens expire, but they do, otherwise there wouldn't be an option to give offline permissions.
Anyway, sometimes requiring the user to give offline permissions is an overkill. Depending on your needs, maybe it's enough that the token remains valid as long as the website is opened in the user's browser. For this there may be a simpler solution - relogging the user in periodically using an iframe: facebook auto re-login from cookie php
Worked for me...