issue: OAuth oauth_problem="parameter_absent: oauth_signature", realm="yahooapis.com"

according to yahoo API official online document, i exploring oauth with yahoo & i want to grab yahoo contacts by using url: [url]http://social.yahooapis.com/v1/user/GUID/contacts[/url]
i have got some information as step 5 of oauth show in [url]http://developer.yahoo.com/oauth/guide/oauth-refreshaccesstoken.html[/url]
And now, i’m using CURL to load: [url]http://social.yahooapis.com/v1/user/GUID/contacts[/url] to grab contacts list
my code here:

[code=php]//starting load contact
$get_contacts_url=”http://social.yahooapis.com/v1/user/”.$xoauth_yahoo_guid.”/contacts”;

$auth_header=array(
‘Authorization:OAuth’,
‘realm:yahooapis.com’,
‘oauth_consumer_key:dj0yJmk9eTYxaGMxczNqUW1iJmQ9WVdrOWJGZEdZVkpDTldNbWNHbzlNVFU1TXprMU56UTJNZy0tJnM9Y29uc3VtZXJzZWNyZXQmeD1jZQ–‘,
‘oauth_nonce:abc’,
‘oauth_signature_method:PLAINTEXT’, //HMAC-SHA1
‘oauth_timestamp:’.time(),
‘oauth_token:’.$_SESSION[‘oauth_token’],
‘oauth_signature:387892fe58f962859758bbb278dd7a4c37bd4dd6&’.$_SESSION[‘oauth_token_secret’],
‘oauth_version:1.0’
);

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $get_contacts_url);
curl_setopt ($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt ($ch, CURLOPT_HTTPHEADER, $auth_header);

echo curl_exec ($ch);
curl_close($ch);[/code]

But i still get issue: Please provide valid credentials. OAuth oauth_problem=”parameter_absent: oauth_signature”, realm=”yahooapis.com”

People can help me? I wondering this message. I dont any treat with this problem.

Also in #PHP _↴