Facebook Messenger subscribed apps, page and app access token generation - facebook-graph-api

I am hitting a wall while developing seamless integration of a Facebook page with my bot.
Essentially I want to achieve same integration than Chatfuel or Manychat have, where being logged in with your Facebook account lets you to just choose what page you are connecting to them and you are good to go.
The problem I am facing is generating the proper token in order to bind the selected page to my app (bot). As per Facebook documentation:
When you create a subscribed_apps edge, the page-id you use in endpoint must match the page ID of the page access token used in the API call. The app that the access token is for is installed for the page.
Given the call has no other parameter than the access token, this access token has to be enough for Facebook to:
Authorize the action on the page.
Identify what app is being subscribed to the page.
This is confirmed while using the Facebook Graph API Explorer, where one selects the page and the app to bind and a proper access token is generated:
This token properly works using cURL in the terminal:
$ curl -X POST 'https://graph.facebook.com/v3.0/<MY_APP_ID_HERE>/subscribed_apps?access_token=<TOKEN_PASTED_FROM_GRAPH_API_EXPLORER>'
{"success":true}
With the Facebook Access token debugger (info icon on the left of the access token, then open in Access token tool), it is confirmed that the token knows about both the page and the app that have to be connected.
The question is, how are these page-app related token programmatically produced? I can't seem to find the proper API call in Facebook documentation and it is by all means possible, as Chatfuel and Manychat are doing this.
Thanks in advance for your support Lars Schwarz and community!

Adding some detail to Alex's answer, for it to be more complete.
When subscribing an app to a page, Facebook needs to:
Know what app you are talking about.
Know what page you are talking about.
Know that you have permissions on that page to subscribe an app.
How does Facebook know it all?
1 comes from the fact that Facebook login happens in the context of a page, actually, the Javascript code for Facebook contains your appId:
js.src = 'https://connect.facebook.net/en_US/sdk.js#xfbml=1&version=v3.0&appId=<YOUR_APP_ID_IS_HERE>&autoLogAppEvents=1';
2 Comes from the page_id in the URL used to subscribe apps to pages:
https://graph.facebook.com/v3.0/YOUR_APP_ID_HERE/subscribed_apps?access_token=YOUR_ACCESS_TOKEN_HERE
3 Comes from the access token, obtained in the context of an APP through Facebook login, that is passed as parameter in the URL used to subscribe apps to pages:
https://graph.facebook.com/v3.0/YOUR_APP_ID_HERE/subscribed_apps?access_token=YOUR_ACCESS_TOKEN_HERE

To do this, you need to put FB Login on your site/customer portal and request pages_messaging and manage_pages permissions. The person that logs in must be a Page Admin.
Once your app has been granted that permission for the page, you can generate a page access token as described here:
https://developers.facebook.com/docs/pages/access-tokens

Related

Graph API: All Mutual Friends Returning Empty List

All mutual friends request made from my app server (node) (also tried the Facebook API explorer) suddenly started returning an empty array for the data field. I confirmed and validated my access token and appsecret_proof on the API explorer. Do you know what has changed or what the request below is missing?
Note: both users use the app and have granted user_friends permission.
I am using v2.12
request
{
url: 'https://graph.facebook.com/v2.12/{user-facebookid}?fields=context.fields(all_mutual_friends.limit(5000))',
qs: {access_token: 'XXXXX'
,
appsecret_proof: crypto.createHmac('sha256', clientSecret).update(accessToken).digest('hex')
}
Yep. Facebook has taken down the Graph API for page access tokens. The only way to retrieve data (or was a week or so ago), was a temporary user token that lasts about 2 hours. It's totally broken my band's schedule page. I've been through every avenue and even spoke with a facebook ad team employee on the phone that was aware of it. She seemed to empathize but had no solution for me. I would count on it being down for a while.
I have finally figured out a work around for this. On your fb application, you have to disable the secret key requirement. This can be found under the advance settings of your fb application console. It's called "
Require App Secret".
Once you generate a fb PAGE access token, you get a fb page token, and then extend it.
here is the token debugger:
https://developers.facebook.com/tools/explorer/
You can extend the access token programmatically as explained here:
https://developers.facebook.com/docs/facebook-login/access-tokens/expiration-and-extension
AND
https://developers.facebook.com/docs/facebook-login/access-tokens/#pagetokens
There is also an extend tool in the access token debugger.

Retrieve Facebook profile from Xamarin client

I would like to get basic user information from Facebook after the user has logged in.
I've looked at the documentation in How to: Work with authentication and under the "How to: Retrieve authenticated user information" section, it shows how to do it from the .NET backend code by using an HttpClient to make the call with the AccessToken:
var fbRequestUrl = "https://graph.facebook.com/me/feed?access_token="
+ credentials.AccessToken;
Since the mobile client has the accessToken that we get from MobileServices, can the client make the call directly to a Facebook endpoint, or does the client SDK provide us with any built-in functionality?
I've been following the Xamarin.Forms Sport project and the way they get the user information from Google is by hard-coding the Google endpoint and making a call to get the user info.
Note: Xamarin.Forms Sport uses Mobile Services, not Mobile App, so not sure if that makes any difference.
It sounds like you're doing the server-directed login: where you are making a call to your backend to do the login dance with Facebook. In this, your client application is making a GET call to .auth/login/facebook, which opens up a browser or the Web Authentication Broker where you enter your credentials. The end result is you will receive a Zumo access token (different from Facebook access token).
You cannot use the Zumo access token to access Facebook APIs by itself. In the "How To:" you linked, we show you how to use GetAppServiceIdentityAsync from the backend to get the Facebook access token. This is possible because you have stored your Facebook client ID via portal, which is available to the backend.
The advantage of doing auth like this was that you don't have to deploy your Facebook Client Id with your mobile apps. If you wanted to access the Facebook APIs from the client, though, you'll need to get the Facebook token to the client.
Few ways I can suggest:
Call .auth/me from your client. The response will give you a JSON object you can parse that should include the FB token associated with your Zumo token.
Write a custom API with [Authorize] attribute set that will perform GetAppServiceIdentityAsync and respond with the value of the facebook access token. You can then parse the response from your client. This is basically what .auth/me does, but you can write it to give back only your FB access token.
Use the Facebook .NET SDK http://facebooksdk.net/ to do client-directed login. You will get a Facebook token on your client, and then you can use our LoginAsync(Facebook, access_token) method to get a Zumo token so that your client can access both Facebook and your Mobile App backend. The disadvantage, as I mentioned before, is that you'll have to deploy your FB Client ID with your app.

Facebook Graph API - complete server side auth and API calls

I have an application, that runs on server. On that server is background task, that will post status update on few social networks (Facebook, Twitter, G+). It must be completely server-side.
In Twitter API I'm able to use OAuth header to authorize API request. OAuth HTTP header uses consumer key, consumer secret, access token and access token secret to create the header. With this I'm able to post/update/delete tweets with no user interaction.
How can I do this for Facebook? I found a solution to obtain a long-lived access_token (2 months), but we don't want to regenerate access_token every 60 days. We want to use it for manage our Facebook page - post status updates, but completely server-side.
Am I able to do this for Facebook? Thanks for answers.
PS: I searched stackoverflow hundred-times but with no solution for my problem.
Thanks.
It is not possible for User Access Tokens (they can only be extended to 60 days and need to be refreshed by the user after that), but for posting to a Page you should use a Page Token anyway. An Extended Page Token is valid forever.
Here are some Links to help you get that Extended Page Token:
https://developers.facebook.com/docs/facebook-login/access-tokens/
http://www.devils-heaven.com/facebook-access-tokens/
http://www.devils-heaven.com/extended-page-access-tokens-curl/
A Page Token will post "as Page" btw, but that´s probably what you want. And auto-posting on user profiles is not really allowed anyway, every message has to be 100% user generated and every posting should get authorized by the user.
Pay attention to Access Tokens Expiration & Extentions.
The Page Access Token could be a good solution to only server side calls for testing and data analysis purposes.
Take your User Access Token from Graph API Tool
Extend your User Access Token
Call https://graph.facebook.com/v2.11/me/accounts with your user access token extended
*all calls are GET and this procedure does not use APP Access Token.

Facebook Access Token questions

I'm playing around with Facebook Connect, trying to use Facebook as the means or authentication on my site. Currently my workflow looks something like this:
Go to URL
Server checks cookies for AccessToken
If AccessToken exists, automatically fill in user's name/profile picture in comment box, and leave AccessToken in hidden input
send page down to client
on submit, verify access token (which was submitted with the rest of the form) is a valid access token for a real person. If so, add comment to Database
refresh page to display new data
if no access token, replace user's name/profile picture with <fb:login-button>, along with the required <script>s.
send page down to client
When user authorizes page/logs into facebook, refresh page
(go back to top, except this time the access token should exist)
So I have a few questions:
Is this secure? I was thinking of ways i would be able to do without the double authentication with Facebook (checking once on page-generation and checking again on comment-submission), and I could not figure any other way short of maintaining my own session-state with each client. Is that worth doing?
Does the access token expire when i log out of Facebook? I'm thinking it should, but it seems I can continue to use the same access token to grab data (i.e. name, url, etc.) after I manually go to Facebook and log myself out. Is it because I'm only asking for public information, and only more intrusive permissions expire on logout?
Given that each person who wants to do something has to provide a unique token from Facebook, this should have the side effect of blocking CSRF, since every action can be traced to a valid Facebook account. Is that right?
Why don't you just use the Facebook Javascript SDK to detect if they're currently logged into Facebook? This will also make the access token available in Javascript so you can make client-side calls to the API.
You can access the same access token server side via the session cookie set by Facebook also.
I can't answer all of your questions but I can tell you that having the access token in a hidden field on your page is risky from a policy perspective, especially if your page can be read by any third-party code such as Google Analytics or AdSense. Facebook will nail you for this as it is leaking user identifying data to third parties. The Facebook userid is in the access token in plain text. Facebook has automated processes that scan for this stuff and will auto-ban your app if it is leaking userids to third parties.

Facebook API get user accesstoken for app

I am posting to my facebook wall through my app using my user.
I gave to the app offline access but still, sometimes the accesstoken changes.
I would like to know if its possible to use Facebook API to get the accesstoken?
Right now, I used the example.php from the facebook sdk to login and took the accesstoken from there.
again, I dont want the application accesstoken. I want to user accesstoken of using the app.
Thanks.
There is App Login section in Authorization paragraph in https://developers.facebook.com/docs/reference/api/ .
Read it. You have to call it if you get invalid access token error in order to refresh the token. However, sometimes the token is invalid due to lack of permissions and not because the token is expired