$oauth_nonce = md5(uniqid(rand(), true));
$oauth_timestamp = time();


$oauth_base_text = "GET&";
$oauth_base_text .= urlencode(URL_REQUEST_TOKEN)."&";
$oauth_base_text .= urlencode("oauth_callback=".urlencode(self::getRedirectUrl('oauth_twitter'))."&");
$oauth_base_text .= urlencode("oauth_consumer_key=".TWITTER_APP_KEY."&");
$oauth_base_text .= urlencode("oauth_nonce=".$oauth_nonce."&");
$oauth_base_text .= urlencode("oauth_signature_method=HMAC-SHA1&");
$oauth_base_text .= urlencode("oauth_timestamp=".$oauth_timestamp."&");
$oauth_base_text .= urlencode("oauth_version=1.1");


$key = TWITTER_APP_SECRET."&";

$oauth_signature = base64_encode(hash_hmac("sha1", $oauth_base_text, $key, true));

$url = URL_REQUEST_TOKEN;
$url .= '?oauth_callback='.urlencode(self::getRedirectUrl('oauth_twitter'));
$url .= '&oauth_consumer_key='.TWITTER_APP_KEY;
$url .= '&oauth_nonce='.$oauth_nonce;
$url .= '&oauth_signature='.urlencode($oauth_signature);
$url .= '&oauth_signature_method=HMAC-SHA1';
$url .= '&oauth_timestamp='.$oauth_timestamp;
$url .= '&oauth_version=1.1';

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_setopt( $ch, CURLOPT_COOKIESESSION, true );
$response = curl_exec($ch);
curl_close($ch);

parse_str($response, $result);

$_SESSION['oauth_token'] = $oauth_token = $result['oauth_token'];
$_SESSION['oauth_token_secret'] = $oauth_token_secret = $result['oauth_token_secret'];

$url = URL_AUTHORIZE;
$url .= '?oauth_token='.$oauth_token;