如何对来自Facebook API的图像进行base64编码

Question

I am attempting to convert an image url provided by the facebook api into base64 format with cURL.

the api provides a url as such:

https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-xfp1/v/t1.0-9/p180x540/72099_736078480783_68792122_n.jpg?oh=f3698c5eed12c1f2503b147d221f39d1&oe=54C5BA4E&__gda__=1418090980_c7af12de6b0dd8abe752f801c1d61e0d

The issue is that the url only works with the oh, oe and gda parameters included in the url string, there is no direct img url. Removing the params send you to a facebook error page.

With the parameterized url my curl_exec is not getting correct image data. Is there a way to get the base64 data from facebook, or is there something I can do to get access the pure image url given the parameterized url?

This is what my decode scrip looks like:

header('Access-Control-Allow-Origin: *');

  $url = $_GET['url'];

  try {
        $c = curl_init($url);
        curl_setopt($c, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($c, CURLOPT_CONNECTTIMEOUT, 3);

        $result = curl_exec($c);
        curl_close ($c);

        if(false===$result) {
           echo 'fail';
        } else {
           $base64 = "data:image/jpeg;charset=UTF-8;base64,".base64_encode($result);
           echo $base64;
}
} catch ( \ErrorException $e ) {
    echo 'fail';
}

Answer 1

To address your specific problem, your script is likely failing because the required oh , oe , __gda__ parameters are getting separated during the GET request and therefore are not included in $_GET['url'] .

Make sure you're using a URL-encoded string so any unencoded & characters aren't handled as delimiters. Then just decode the string before passing it on to cURL.

...

$url = urldecode($_GET['url']);

...

---

For anyone curious, you can still load any Facebook image from any one of their legacy CDNs without needing the new parameters:

1. https://scontent-a-iad.xx.fbcdn.net/hphotos-frc3/
2. https://scontent-b-iad.xx.fbcdn.net/hphotos-frc3/
3. https://scontent-c-iad.xx.fbcdn.net/hphotos-frc3/

Just append the original image filename to the URL et voila .

Disclaimer: I have no idea how long this little trick will work for so don't use it on anything important in production.

Answer 2

Maybe this won't help much but it seems that the original picture (ending with _o ) does not need gda nor oe oh parameters

to get the original profile picture you can do:

var username_or_id = "name.lastname" //Example
get_url ("http://graph.facebook.com/$username_or_id/picture?width=9999")

hth

Answer 3

I had similar problem. My solution:

$url = urldecode($url);
return base64_encode(file_get_contents($url));

Where the URL is to Graph API:

https://graph.facebook.com/$user_id/picture?width=160

(You probably want to also check, if file_get_contents returns something)

Answer 4

You just need to add the CURLOPT_SSL_VERIFYPEER set to false as the url from facebook is https and not http. , or you could just as well request the url without ssl by replacing https with http.

Try the code below

    $url = 'https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-xfp1/v/t1.0-9/p180x540/72099_736078480783_68792122_n.jpg?oh=f3698c5eed12c1f2503b147d221f39d1&oe=54C5BA4E&__gda__=1418090980_c7af12de6b0dd8abe752f801c1d61e0d';

try {
    $c = curl_init($url);
    curl_setopt($c, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($c, CURLOPT_CONNECTTIMEOUT, 3);

    /***********************************************/
    // you need the curl ssl_opt_verifypeer
    curl_setopt($c, CURLOPT_SSL_VERIFYPEER, false);
    /***********************************************/

    $result = curl_exec($c);
    curl_close ($c);

    if(false===$result) {
       echo 'fail';
    } else {
       $base64 = '<img alt="Embedded Image" src="data:image/jpeg;charset=UTF-8;base64,'.base64_encode($result).'"/>';
       echo $base64;
    }
} 
catch ( \ErrorException $e ) {
    echo 'fail';
}