I created an app and an offline access token so I could display a news feed on my website without requiring a Facebook login. I created two test versions in PHP and JavaScript that work fine. But I took down the JavaScript version because I was concerned about the lack of security in explicitly stating the access token in a client-side script. Is server-side the only way to go for security reasons?
I think you are correct to take out your access token from javascript. As long as that access token is valid - even if it hasn't been obtained with offline_access permissions - it can be used to perform actions on behalf of that user/app/page. All you need to make calls is the user/app/page ID which is easily obtainable and a valid access token...
I recommend you leave your access token management to your server-side scripts. Perhaps making ajax calls to refresh the posts at regular intervals...
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I am the administrator of a Facebook Page. I am building a web app which, under certain circumstances, will post on Facebook as that Page.
With most APIs, I would just get an API key, and supply that when connecting to the API from my app. But Facebook expects an access token instead of an API key. (Specifically, in this case, it needs a "page access token".)
I am trying to figure out how to get a page access token that will be as permanent as possible.
After jumping through a bunch of esoteric, undocumented hoops (see here and here) in order to get a token that wouldn't expire, I had this working. When I ran the token through Facebook's Access Token Debugger, the "Expires" field read "Never". All was good in the world.
But, the next day, my token became invalid anyway. The Access Token Debugger, and my app's calls to Facebook's PHP SDK, both started returning this error:
Error validating access token: Session does not match current stored session. This may be because the user changed the password since the time the session was created or Facebook has changed the session for security reasons.
It seems that a token can become invalid for a variety of reasons (but this article is five years old, so who knows – Facebook changes things every two weeks). I had not changed my password. (I might have logged out of Facebook, though.) Facebook offers no specifics about why this particular token might have become invalid.
I've also seen a few references to a permission called offline_access, but Facebook seems to have removed this.
I suppose my question is twofold:
In general, I've found Facebook token authentication to be incredibly brittle when calling the Facebook API from the server. The token system seems to be designed mainly to allow other users to grant (or revoke) various kinds of account access to my apps. But that's not what I'm doing – I'm trying to get a token that will let me post to a page that I own. And for that scenario, Facebook's aggressive invalidation of tokens becomes a serious liability. I can't launch my app if my access token (and therefore my Facebook integration) could randomly stop working at any moment, requiring me to generate a new token and update the app. This seems absurd. Is there an alternative method of authenticating to Facebook for my purposes?
If a page access token is, in fact, the best way to authenticate my app to Facebook in order to post as my Page: how can I ensure that my token doesn't spontaneously become invalid?
I hate developing for Facebook :/ Thanks for any insight you can offer.
Extended Page Tokens are valid forever. They only get invalidated if you change your password or if you change the App Secret of your App. There´s really no magic in it, checking if the Token is still valid is obviously not a bad idea but that´s up to you. For example, you can send yourself an automated Email when there is an error using the Token, so you can refresh it. But it will really just happen if you change your password.
Links:
https://developers.facebook.com/docs/facebook-login/access-tokens
http://www.devils-heaven.com/facebook-access-tokens/
My app logic (Android, iOS and Web) is all written in my server.
Since things got complicated, I decided to build my server as a REST web service so querying it will contain logic in the header.
My login flow is pretty simple, and I somehow tried to copy from Facebook API:
The user login to Facebook.
The user receive a Facebook access token
The access token is sent to my server with some other identifiers
The server checks with Facebook that the access token is valid with Facebook and that the other identifiers match the ones on Facebook.
The server returns an access token to the user, which he should use in each query until it expires.
The problem is that I didn't add any other restrictions like endpoints limitations (scopes) and stuff like this, so an access token generated by my server grant you access to each part of my api.
I think that inventing the wheel here will be foolish, so I'm looking for a framework or a generic solution that will allow me to add logic to the access tokens in a simple way.
I read about OAuth, but my concern that its more about user sharing with other users, but I only want to use it is login flow and scope protector.
Is it possible with OAuth ? Are there alternative to OAuth ?
That's possible with OAuth 2.0 and in fact one of the objectives: you may issue and use access tokens that have particular "scopes" (an OAuth 2.0 concept) associated to them that could relate to permissions that the client has (e.g. read/write, API A, API B).
But you need to issue your own access tokens from your own Authorization Server. You could allow users to login to that Authorization Server with their Facebook account.
Using app access token had previously been asked in this question (How to use Facebook appAccessToken with Spring Social) and Craig Walls gave a good explanation why the spring-social API should be user-based for most cases.
I have a scenario, however where I would like our server-side application to make a couple of queries that should not require user-specific permissions. I picked a random public page for examples below
I would like to:
View details about a public page by alias/id
https://graph.facebook.com/v2.0/121727254549188
https://graph.facebook.com/v2.0/peterstevensmotorcycles
View posts for a public page by alias/id
https://graph.facebook.com/v2.0/121727254549188/posts
https://graph.facebook.com/v2.0/peterstevensmotorcycles/posts
Search for pages
https://graph.facebook.com/v2.0/search?q=Peter%20Stevens%20Motorcycles&type=page
When I test these in the Graph API explorer (https://developers.facebook.com/tools/explorer) using an App Access Token they work fine. App Access Token is obtained by hitting https://graph.facebook.com/v2.0/oauth/access_token?client_id={app-id}&client_secret={app-secret}&grant_type=client_credentials and replacing client_id and client_secret with my Facebook client credentials.
Our application would like to have the ability to make these for any given name so we can make queries about a company's presence.
We will have similar requirements for Twitter, LinkedIn and others so I just wanted to check if there are any means to do this in the current API or whether it will not suit our requirements.
You do not need to fetch an app access token - you can actually use the app id and secret separated by "|" as the access token. - You can see it at the bottom of the app access token section in the documentation: https://developers.facebook.com/docs/facebook-login/access-tokens#apptokens
Spring Social's Facebook API binding does not (yet) support v2.0, but that's something I'm working on right now...so hopefully soon. Once that's complete, there'll certainly be some operations that work only with user access tokens and some that only work with app access tokens, and some that will work with either (FWIW, Twitter's API has a similar set of circumstances).
Keep an eye on the project in GitHub or follow #SpringSocial on Twitter to know when the v2.0 stuff is available. (I'd appreciate any help I can get in testing it.)
Although it makes no sense at all to obtain your FacebookTemplate via the connection framework for app token requests (connections are, by nature, a user-oriented concept), you can always construct a FacebookTemplate wherever you need it, giving it an app access token obtained via OAuth2Template's authenticateClient(). You can certainly do that now with the v1.0 API binding, but I'm uncertain what ops an app token would work with.
FWIW, as I'm working on the v2.0 API binding, I'm starting to sense an opportunity for FacebookTemplate to carry two tokens: A user token and an app token. This way you can perform app-centric requests even from a FacebookTemplate obtained from the connection framework. Then the only time you'd ever want to construct a FacebookTemplate manually is if there are some operations for which either kind of token will work, but the results would be different depending on what type of token is used.
On my app the user can sign to Facebook and the app then has the user's access token (say it's 'abc'), I want to use this token to create a user on my own server.
Is it safe to send this access token to my server (using SSL), then get the user's username and ID using https://graph.facebook.com/me?access_token=abc on my server and check that the application the token belongs to is mine with https://graph.facebook.com/app?access_token=abc. If it is my application I then store the user in my user's database and/or log them in.
Can this system be fooled? Can you think of a way someone could log in as someone else?
You should check out all of the Authentication documentation and the Oauth spec to see the different auth flows available
Broadly speaking, you can create a user on your server based on the access token, and be reasonably certain that when you get an access token from Facebook for the same user ID that it's the same person.
If you require very high security for the app you can take steps to ensure the user's access token wasn't produced via malware or the Facebook user being tricked, there's an example showing protection against CSRF in the Server Side Authentication documentation, and there's also a reauthentication flow you can use
I assume that you are using facebook sdk for this, if so the facebook sdk takes care of the security for you and you don't have to worry about a thing.Supposing that you are accessing the api without the sdk then there are two things that must be noted:
1) Auth token expires frequently(facebook has taken great pains to ensure that the user is protected)
2)Making a request with just auth token is not enough there are some other parameters that are needed that can't be faked especially if you are doing this server side since an extra layer is added that fb calls server flow authentication
3)On top of that there are a lot of permissions that are in place that the user has to give in order for an application to access some data.The link below provides a nice article on authentication you can take a look
https://developers.facebook.com/docs/authentication/
So long story short it is safe.
I need to post message on a certain FB page as a owner by cron, using php and ZF 1.1.X. For this small issue, I don't want to create a full OAuth stack. Is it possible to communicate with FB API (it's desirable, PHP SDK for FB) without it, such as twitter with his precreated access tokens (Access token, Access token secret)?
As long as you need an active user access_token to retrieve desired data this is not possible to skip OAuth flow.
Without authenticating user you only have application access_token (in old format APP_ID|APP_SECRET, but it's still works) and only limited access to most of Graph API endpoints and Application settings.
Actually there is nothing hard in implementing the user authentication with OAuth flow and it is completely transparent with usage of PHP-SDK.
Just look at the sample code in documentation for server-side authentication
Yes, you need to build an app and then authorize the page via the app while requesting the manage_page permission.
You should make yourself familiar with the Server Side Auth process as well.