How to pass access token from one website to another? - facebook

I have a website that takes care of getting a Facebook token through Graph / OAuth. At that point, the website can post to the user's Facebook wall with no problems.
Is it possible to send this token to another website so the remote website can start posting the user's Facebook wall without re-logging in the user?

Access tokens are granted per APP ID, not per domain
That being said, unless your access token includes the offline_access permission, access tokens are bound to the current session so even if you managed to "pass" it to another domain, it wouldn't work if the user was logged out (of Facebook).
So, yes it should be possible under the right circumstances.

Related

How to use Facebook access token to post to a users wall indefinitely

I'm using the facebook sdk 2.7 to prompt the user to login in to their facebook account and then to be able to post to their wall from our website. This works fine but each time the user visits the website they need to login again.
I do retrieve the user access token when they login. Can I use this to enable the website to always be able to post to the users wall without them having to log in to facebook each time?
You would need to use an "Extended User Token" for that, it is valid for 60 days. Btw, you are not allowed to autopost and the message always must be 100% user generated. So make sure the user approves and writes every single post.
How to create Extended User Tokens is explained in the docs:
https://developers.facebook.com/docs/facebook-login/access-tokens
http://www.devils-heaven.com/facebook-access-tokens/

Posting to a Facebook Page Wall from a Web Server

I've been reading documentation and Stack Overflow link all morning, but I'm just not understanding the correct process to authorize a web server to post to a Facebook page wall.
What I'm not clear on is why I have to post to Facebook as a Facebook User, using an access_token, meaning that this user has to log into Facebook manually to authorize my app.
I'm not trying to authorize a User, nor any of my visitors to do anything with their accounts, so I don't need any permissions from them. Instead, I'm trying to authorize my Web Server to post updates to its wall as a specific Page.
Why do I have to use a user access_token to do this? I'm not attempting to impersonate the user, I'm trying to post to the page as the page...
Is it possible to authorize a user and get their access token without having to create a login page on the Web Server? I don't want to have to require the user to login to make this work, I thought that was the point of having an app ID and Secret?
I guess my question is this: Is it not possible to allow a web server to post to a Facebook page wall as that page, without having to present a login dialog to a specific user? If it is possible, what is the correct workflow to set this up?
In order to post to a Page as a Page, you have to use a Page Access Token. You get that with a User Access Token, and you can extend it so it will stay valid forever.
Steps:
Request a User Access Token with the manage_pages permission (valid for up to 2 hours)
Extend the User Access Token (valid for up to 60 days)
Get the Extended Page Access Token for your Page with the User Session
Store and User The Page Access Token in the publish call
It may sound a bit complicated, but there are many tutorials for this and you donĀ“t actually need to program it, you can just use the Graph API Explorer.
Here are some Links about the Access Tokens:
https://developers.facebook.com/docs/facebook-login/access-tokens/
http://www.devils-heaven.com/facebook-access-tokens/ (see "Extended Page Access Token" for a step by step tutorial)

Facebook: Posting to my own wall through the API

I want my application to post to a single, pre-defined user's wall something like "We just posted a new blog at [URL]" with no client-side interaction.
But every answer I can find on this topic seems to hinge on getting an access token through
https://graph.facebook.com/oauth/access_token
Which gives you some redirect url through which a user has to log in manually.
I've got near zero experience with Facebook. Is it possible to automatically get an access token for a predefined user? Am I doing it wrong? ;)
You can't.
Facebook doesn't give you a way to automatically get an access token for a user. That user needs to log into Facebook and explicitly give your app permission. The best you can get is a long-lived access token that remains valid for up to 60 days.
Getting that token requires a two step process:
1) Logging into Facebook using either the JavaScript API or redirecting the user to a valid Facebook login URL.
2) Retrieving the short-lived access token you got in step 1 for a long-lived access token.
Once you've got that access token, should your post fail, you know you need to re-authenticate the user and get a new long-lived access token. Your user needs to be online and logged into Facebook for this to work, though it can happen without their interaction.

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.

is it possible to access user's wall info without passing his/her access token?

I wonder is it possible to access user's wall info without passing his/her access token?
for example, I will just pass my app secret token and app id. and FB user already allows to access his/her info from my app. Facebook does the checking and matching of my app and my app's user by just using my app secret token and app id.
Because I found some topics similar to that.
http://forum.developers.facebook.net/viewtopic.php?pid=9172
When I check Rest FB doc,it says like that.
http://restfb.com/javadoc/index.html
public DefaultFacebookClient()
Creates a Facebook Graph API client with no access token.
Without an access token, you can view and search public graph data but can't do much else.
I doubt that it will work or not without access token.
can everyone share me ideas or any possible similar approaches ?
Thanks.
You will need to ask the users to authorize your app for offline access. You will be able to access the user's wall even if the user is offline, but you still need the access token. It is part of Facebook's security measures.
There are two types of access tokens:
Session based: expires in a short term, are used when the user will be logged to FB every time you need to perform an operation.
Offline access: do not expire and allow the app to perform operations for the user in any moment. This requires the offline_access permission when the app is authorized.
Check here: http://developers.facebook.com/docs/authentication/ for the oauth mechanism and here: http://developers.facebook.com/docs/authentication/permissions/ for the permissions list.
The REST API is deprecated and it is strongly suggested that you don't use it anymore. Furthermore, from this October you will be allowed to use only the Oauth2 authentication (see When is Facebook turning off their session based auth?)
Without token you can only access public information.
Public data
From RestFB homepage :
// It's also possible to create a client that can only access
// publicly-visible data - no access token required.
FacebookClient publicOnlyFacebookClient = new DefaultFacebookClient();
If the user does not protect his posts, then you can access everything without token. But most of user do protect their data and then you need a valid user access token to read the data.
Private data
When you say "FB user already allows to access his/her info from my app" it means that the user has clicked on "Allow app" in the web browser and at that moment here Facebook will give you a token. You can after use that token with RestFB :
FacebookClient facebookClient = new DefaultFacebookClient(USER_ACCESS_TOKEN);
User user = facebookClient.fetchObject("me", User.class);
out.println("User name: " + user.getName());
By default, the token will expire a few hours later. If you ask for the offline_access permission, the token will be valid for ever (as long as the user does not remove the permission for your app in his settings). You should store that token in your database to be able to use it when you need.
Get the user token
You cannot get the user token with RestFB. On the RestFB homepage, you can read :
Non-goals: [...] Providing a mechanism for obtaining session keys or OAuth access tokens
Because you need a browser to do so : the user has to authenticate and authorize your app on Facebook website (the popup that shows).
What you can do is to have a PHP page on which your users have to go to authorize your app. You can read this stackoverflow answer that explains how to use the Facebook PHP SDK to do so.
Hope that helps !