OK, apologies for the verbose title. Let me give the background in a bit more detail.
My website allows my registered users to create new pages, each of which has its own unique URL. Each page has a Facebook “Like” button on it. I’ve already implemented Facebook Open Graph API meta tags so that the pages are proper open graph objects, and when some other visiting Facebook user “likes” the registered user’s page, a post appears on that Facebook user’s wall saying they have liked the page. The Facebook Like widget also displays the number of “likes” that page has received as normal. So far, so good.
What I want to do is allow my registered users to be able to communicate back to the Facebook users who have liked their page. The community of “likers” for a page is a potentially valuable social media resource to the registered user, if only they could communicate back.
I am aware of the “admin page” link you get beside the Like button, which can be used to post to these people, but that is not an option for my registered users as they have no privileges in relation to the Like button.
What I want to do, if possible, is setup a form to capture the registered user’s message back to the Facebook users, and then my website sends the message on their behalf, without having to ask for any extra privileges from the Facebook users.
The following Facebook documentation pages seem to say this is possible, but having followed the Open Graph API documentation, I can’t get it to work as described – http://developers.facebook.com/blog/post/465/ and http://developers.facebook.com/docs/reference/api/ (“Publishing” subsection). I can get the access token correctly in the first request, and plug that into the second request to do the post, but that doesn’t seem to do anything and doesn’t return any error.
Since it doesn’t work for me, I’m wondering if this is possible as described, or do I need to get some sort of extra permission to do this? I’ve seen reference to offline_access permission but as I’m new to this stuff I am not sure how it would fit in. If I have to get the Facebook users to grant permissions, this is not going to work as envisaged.
Any thoughts would be most helpful.
The short answer: No, You will never been able to post on someones wall as another user.
The long answer:
You could try to ask for offline access but then you are asking the user to hand over all their facebook data and give you access todo whatever you like their accound, so that is not likely to happend.
The next problem is that they have to be friends to be able to post on each others walls.
Thats why Pages was implemented, so that organisations could announce/talk with the people interested.
However if you have created the like button correctly and give the pages correct meta data, you are able to post to user who have liked it.
Scroll down to Publishing:
http://developers.facebook.com/docs/opengraph/
Just add a form for your user and let your system publish to the correct page, you probably will need a offline token from your own account or similar to use on the server.
Another more complex way could be to generate a facebook page for each page you have on your server.
When the user creates a page on your system a page is created on facebook but as your app as admin.
And when another user likes the page they like the facebook page, hence you have the possibility to post in that page and speak to the user who liked it. (whooa thats a mouthfull).