OAuth Google Analytics Authentication with PHP - php

Question

I am trying to get OAuth to work with Google Analytics, but I'm not having any luck. My code looks like this:
require_once('common.inc.php');
$consumerKey = "my.url.net";
$consumerSecret = "nzZ....TX";
$sig_method = "HMAC-SHA1";
$oauth_token = $token ? new OAuthToken($token, $token_secret) : NULL;
$token_endpoint = '/accounts/OAuthGetRequestToken';
$scope = 'https://www.google.com/analytics/feeds/';
$callback_url = "http://my.url.net/pete/oauth/";
$privKey = NULL;
$params = array('scope' => $scope, 'oauth_callback' => $callback_url);
$url = $token_endpoint . '?scope=' . urlencode($scope);
$consumer = new OAuthConsumer($consumerKey, $consumerSecret);
$req = OAuthRequest::from_consumer_and_token($consumer, $oauth_token, 'GET',
$url, $params);
//$req->sign_request($sig_method, $consumer, $oauth_token, NULL);
echo "<PRE>";
print_r($req);
// Fill response
echo json_encode(array(
'html_link' => '',
'base_string' => $req->get_signature_base_string(),
'response' => send_signed_request('GET', $url, array($req->to_header())),
'authorization_header' => $req->to_header()
));
So when this code runs it prints this:
OAuthRequest Object
(
[parameters:OAuthRequest:private] => Array
(
[oauth_version] => 1.0
[oauth_nonce] => 5f....11
[oauth_timestamp] => 1306433873
[oauth_consumer_key] => my.url.net
[scope] => https://www.google.com/analytics/feeds/
[oauth_callback] => http://my.url.net/pete/oauth/
)
[http_method:OAuthRequest:private] => GET
[http_url:OAuthRequest:private] => /accounts/OAuthGetRequestToken?scope=https%3A%2F%2Fwww.google.com%2Fanalytics%2Ffeeds%2F
[base_string] =>
)
When I uncomment this line:
//$req->sign_request($sig_method, $consumer, $oauth_token, NULL);
The script just fails to load showing Server Error. What am I doing wrong? Any advice would help, thanks!

Answer 1

Thanks for your comment Mark, this was actually because my "$sig_method" variable was actually just a string containing "HMAC..." when it actually needed to be an object called this:
$sig_method = new OAuthSignatureMethod_HMAC_SHA1();
Hope this helps someone in the future!