2010-06-16 10:10:48

Facebook Error Message: Requires valid next URL.

Let me start with asking you a few questions!

  1. Are you having issues with the Facebook API?

  2. Are you constantly getting the error message "API Error Code: 100 API Error Description: Invalid parameter Error Message: Requires valid next URL."?

  3. Are you using the latest official Facebook PHP class?

  4. Are you redirecting using the PHP header() function?

Facebook error

Well,  I might have a solution for you. When calling the function getLoginUrl in the Facebook PHP class, the function will return a HTML encoded string. When outputing this string to your browser, it is rendered/decoded by a browser and this will convert all "safe" charachters to their textual equivalent.  This makes that "&" becomes "&" and "%20" becomes " ".

However, when using the header() function in PHP, this url will not be rendered/decoded and you are basically sending out a garbled request.

header('Location:' . $url);

$url = str_replace('&','&',urldecode($url));
header('Location:' . $url);