Grab the Picture of a Facebook Graph Object

Here's what you need to do to get to the actual location of a Facebook profile picture using PHP cURL (this comes in handy if you plan to store the picture somewhere else). In particular, we can grab the pictures of People, Events, Groups, Pages, Applications, and Photo Albums (these are called objects in Graph API).

You can access the Graph's documentation with regards to Pictures at http://developers.facebook.com/docs/api#pictures.

Let's begin.


STEP 1/2

You need to know the User Id to whom we're gonna grab the picture from. For this tutorial, let's try to use the UID of Google's FB page: 104958162837 .

Append the UID to the Graph API's base url like this:  http://graph.facebook.com/104958162837 .

Then add the suffix /picture to the object URL like this:  http://graph.facebook.com/104958162837/picture .

You can actually view the picture now by using this link: http://graph.facebook.com/104958162837/picture

It looks like this:

STEP 2/2


In the first step, we learned how to construct the URL for viewing an FB picture. And that by clicking on the URL, we are redirected to the actual location of the image.

What we're trying to achieve here is that we wanted to grab the image through PHP per FB Graph object. And the only way for us to locate the image is through the Object URL, the same thing we did in the first Step. That is, by passing the UID of the object to the URL.

Now the question is, how do we do that in PHP?

It's fairly simple. In our CurlHelper class, we use the CURLOPT_FOLLOWLOCATION option for us to follow Facebook's redirection towards the actual picture of the object.

The class has one function. And this takes care of downloading the file from the URL.

class CurlHelper
{
  /**
   * Downloads a file from a url and returns the temporary file path.
   * @param string $url
   * @return string The file path
   */
  public static function downloadFile($url, $options = array())
  {
    if (!is_array($options))
      $options = array();
    $options = array_merge(array(
        'connectionTimeout' => 5, // seconds
        'timeout' => 10, // seconds
        'sslVerifyPeer' => false,
        'followLocation' => false, // if true, limit recursive redirection by
        'maxRedirs' => 1, // setting value for "maxRedirs"
        ), $options);

    // create a temporary file (we are assuming that we can write to the system's temporary directory)
    $tempFileName = tempnam(sys_get_temp_dir(), '');
    $fh = fopen($tempFileName, 'w');

    $curl = curl_init($url);
    curl_setopt($curl, CURLOPT_FILE, $fh);
    curl_setopt($curl, CURLOPT_CONNECTTIMEOUT, $options['connectionTimeout']);
    curl_setopt($curl, CURLOPT_TIMEOUT, $options['timeout']);
    curl_setopt($curl, CURLOPT_HEADER, false);
    curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, $options['sslVerifyPeer']);
    curl_setopt($curl, CURLOPT_FOLLOWLOCATION, $options['followLocation']);
    curl_setopt($curl, CURLOPT_MAXREDIRS, $options['maxRedirs']);
    curl_exec($curl);

    curl_close($curl);
    fclose($fh);

    return $tempFileName;
  }
}

Use the class like this:

...
$url = 'http://graph.facebook.com/104958162837/picture';
$sourceFilePath = CurlHelper::downloadFile($url, array(
  'followLocation' => true,
  'maxRedirs' => 5,
));
...

From here, you can do whatever you want to the image.



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