function readHTTPDigestAuthenticatedFile($host,$port,$file,$username,$password)
{
if (!$fp=fsockopen($host, $port, $errno, $errstr, 15))
return false;
//first do the non-authenticated header so that the server
//sends back a 401 error containing its nonce and opaque
$out = "GET /$file HTTP/1.1\r\n";
$out .= "Host: $host:$port\r\n";
$out .= "Connection: Close\r\n\r\n";
fwrite($fp, $out);
//read the reply and look for the WWW-Authenticate element
while (!feof($fp))
{
$line=fgets($fp, 512);
if (strpos($line,"WWW-Authenticate:")!==false)
$authline=trim(substr($line,18));
}
fclose($fp);
//split up the WWW-Authenticate string to find digest-realm,nonce and opaque values
//if qop value is presented as a comma-seperated list (e.g auth,auth-int) then it won't be retrieved correctly
//but that doesn't matter because going to use 'auth' anyway
$authlinearr=explode(",",$authline);
$autharr=array();
foreach ($authlinearr as $el)
{
$elarr=explode("=",$el);
//the substr here is used to remove the double quotes from the values
$autharr[trim($elarr[0])]=substr($elarr[1],1,strlen($elarr[1])-2);
}
// foreach ($autharr as $k=>$v)
// echo("$k ==> $v\r\n");
//these are all the vals required from the server
$nonce=$autharr['nonce'];
$opaque=$autharr['opaque'];
$drealm=$autharr['Digest realm'];
//client nonce can be anything since this authentication session is not going to be persistent
//likewise for the cookie - just call it MyCookie
$cnonce="sausages";
//calculate the hashes of A1 and A2 as described in RFC 2617
$a1="$username:$drealm:$password";$a2="GET:/$file";
$ha1=md5($a1);$ha2=md5($a2);
//calculate the response hash as described in RFC 2617
$concat = $ha1.':'.$nonce.':00000001:'.$cnonce.':auth:'.$ha2;
$response=md5($concat);
//put together the Authorization Request Header
$out = "GET /$file HTTP/1.1\r\n";
$out .= "Host: $host:$port\r\n";
$out .= "Connection: Close\r\n";
$out .= "Cookie: cookie=MyCookie\r\n";
$out .= "Authorization: Digest username=\"$username\", realm=\"$drealm\", qop=\"auth\", algorithm=\"MD5\", uri=\"/$file\", nonce=\"$nonce\", nc=00000001, cnonce=\"$cnonce\", opaque=\"$opaque\", response=\"$response\"\r\n\r\n";
if (!$fp=fsockopen($host,$port, $errno, $errstr, 15))
return false;
fwrite($fp, $out);
//read in a string which is the contents of the required file
while (!feof($fp))
{
$str.=fgets($fp, 512);
}
fclose($fp);
return $str;
}