How to check if user/app can post on target group wall? - php

Question

I can post on group / page and user wall, but i don't want my app to show error when posting on selected wall, if the selected wall doesn't allow posting so is there any way to know that are we able to post on target wall?
Note: I found two similar questions but they do not pertain to exactly what i want
1 Application able to post on user's Wall
2 How to check the permission whether a friend allow me to post on his wall or not using php sdk
Please discuss in comment before taking any negative action.
Thanks.

Answer 1

AFAIK, there's no way to check exactly the way you want, coz the privacy varies, as you have already said. The only privacy setting that can be queried is the OPEN, CLOSED, or SECRET of group, which can be done by calling the graph api:
`http://graph.facebook.com/$Group_id`
That returns json data that has a field privacy, which will be one of OPEN, CLOSED, or SECRET.
But on top of that you have settings for groups where you can restrict posting to only group admins. And that permission can not be checked.
So i think what you'll have to do is check the returned value, i.e $response after making the post. If the permission is not given, then the returned data looks like this:
{
"error": {
"type": "Exception",
"message": "You do not have permission to post in this group."
}
}
Hence you can check if $response has "error" field, and inform the user accordingly. Somewhat like this: if(isset($response['error'])).
Also check the fql table that represents groups for more info, if you haven't already.

Answer 2

Do you mean how to check if a user has given permission to post on their wall?
try {
// Get the permissions this user has
$call = $this->facebook->api("/me/permissions");
// If they have the permission we require ('publish_stream')
if($call['data'][0]['publish_actions']){
try{
// Do your magic here...
// Also include your access token in the array
$params = array('message'=> 'hello world');
$call = $this->facebook->api('/me/feed','POST',$params);
}catch(FacebookApiException $e) {
$result = $e->getResult(); // prob no permissions
}
}
} catch(FacebookApiException $e) {
$result = $e->getResult();
}
So basically, first check to see if the user has permissions for a particular action, then if they do $call[data][0]['publish_action'] will be a set to 1 (int).
Example output of $call = $this->facebook->api("/me/permissions");
[installed] => (int) 1
[email] => (int) 1
[publish_actions] => (int) 1
I have the above permissions from the user through facebook.