Question

I want to use the Facebook graph API. What I want to do is that if I have email address of a person I want to see if he have a Facebook account with that ID. so I Googled a little and found that i can use this.

graph.facebook.com\search?q=[e-mail]&type=user

where all I have to provide is email ID (In this case it is [e-mail]) so it I will get some output from Facebook databse for the user ID and I might view his profile. The problem is that I cant figure out how to use this URL to start working. I have created an App on https://developers.facebook.com/apps

and got my App ID/API Key and App Secret but I think I need to register a URL their so that I can access the Facebook Database. But I cant find where and How. I didnt found any good documantation or so to guide me around. Can anyone be gracious enpough to let me know what to do ?
PS
I use This code to check for everything is alright :

<?php
require_once("src/facebook.php");

$config = array();
$config[‘appId’] = 'api key';
$config[‘secret’] = 'secret';
$config[‘fileUpload’] = false; // optional

$facebook = new Facebook($config); 
$user = $facebook->getUser();
echo "user = ".$user;
?> 

and it always returns user = 0

Answer 1

getUser will always return 0 if there is no authorization, that is the point of the function; return an authorized user for the application.

If you are looking for Graph API calls not requiring a valid user then you don’t need to use that function. The PHP SDK will use the application token to make calls when no user access token is present.

https://github.com/facebook/facebook-php-sdk/blob/master/src/base_facebook.php#L407