Get first link in Google search for a keyword using PHP

When you search Google for a KEYWORD and click "I am feeling lucky", you got redirected to this url -

http://www.google.com/search?hl=en&q=KEYWORD&btnI=1

You will be redirected to the first result link for that given KEYWORD.

I am not sure but knowing that first link for a KEYWORD may be useful for Search Engine Optimization or research etc.
Here is how we can get that link using PHP.

//Get the headers
$headers = get_headers("http://www.google.com/search?hl=en&q=KEYWORD&btnI=1", 1);
//The url for redirect
$url = $headers['Location'];