Invalid signature uploading photo to flickr

Question

I am using the following code:

<?php
 $token = $_REQUEST['token'];
 $file = $_REQUEST['file'];
 $sig = "xxxxxxxxxxxxxxxxxapi_keyxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxauth_token" . $token;
 $sign = md5($sig);
 $url = "http://api.flickr.com/services/upload/";
 $ch = curl_init();
 /**
 * Set the URL of the page or file to download.
 */

 $body = "api_key=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx&api_sig=" . $sign .         "&auth_token=" . $token . "&photo=" . $file;

 curl_setopt($ch, CURLOPT_URL, $url);

 curl_setopt($ch, CURLOPT_POST, 1);
 curl_setopt($ch, CURLOPT_POSTFIELDS, $body);

 /**
 * Ask cURL to return the contents in a variable
 * instead of simply echoing them to the browser.
 */
 curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
 /**
 * Execute the cURL session
 */
 $contents = curl_exec ($ch);
 /**
 * Close cURL session
 */
 curl_close ($ch);

 echo $contents;
?>

to create my signature for the flickr upload post call. However, it keeps telling me its invalid....what am I doing wrong?

maybe you could have a quick look at my code?

Answer 1

You need to include all of the post parameters, except the photo parameter, in the string (in alphabetical order) that you take the hash of.

See http://www.flickr.com/services/api/auth.spec.html#signing