Incorrect Signature in facebook stream_publish call - magento

Question

I am having a facebook error on stream_publish call. I actually used an extension for Magento for Fconnect. Fconnect & Flogin is working fine. But it is requirement that when user place an order it should be posted on user's wall. For that I have implemented like this
document.observe('click', function(e){
if (e.element().match('a[rel^=facebook-connect]') || e.element().match('button[rel^=facebook-connect]')) {
e.stop();
FB.login(function(response){
if(response.status=='connected') setLocation('http://staging.mystore.com/facebook/customer_account/connect/');
}, {perms:"email,publish_stream"});
}
});
in Facebook Client file generateSignature method is like this
private function _generateSig($params_array)
{
Mage::log($params_array);
$str = '';
ksort($params_array);
foreach ($params_array as $k=>$v) {
$str .= "$k=$v";
}
$str .= $this->_secret;
Mage::log($str);
Mage::log('md5 sigs:: ' . md5($str));
return md5($str);
}
& My code that is calling the API is like this
$message = 'just placed an order on mystore.com';
$attachment = array(
'name' => "mystore",
'href' => 'http://www.mystore.com/',
'description' => 'New order on mystore.com',
'media' => array(array('type' => 'image',
'src' => 'http://www.mystore.com/skin/frontend/default/mystore/images/logo.png',
'href' => 'http://www.mystore.com/')));
$action_links = array( array('text' => 'Buy#mystore', 'href' => 'http://www.mystore.com/'));
$attachment = json_encode($attachment);
$action_links = json_encode($action_links);
try{
// if( $facebook->api_client->stream_publish($message, $attachment, $action_links, null, $target_id))
if($this->_getClient()->call( 'facebook.stream.publish',
array($message, $attachment, $action_links,
$this->_getClient()->users->getLoggedInUser(),
Mage::getSingleton('facebook/config')->getApiKey() )
) )
{
Mage::log( "Added on FB Wall" );
}
} catch(Exception $e)
{
Mage::log( "Exception in wall write" );
Mage::log($e);
}
After logging the Signature I found in log is
api_key=XXXXXXXXmethod=facebook.stream.publishsession_key=2.AQCm5fABfobInAS5.3600.1309352400.1-1000025660978090=just placed an order on mystore.comcall_id=1309345883.3068format=JSONv=1.01={"name":"mystore","href":"http:\/\/www.mystore.com\/","description":"New order on mystore.com","media":[{"type":"image","src":"http:\/\/www.mystore.com\/skin\/frontend\/default\/mystore\/images\/logo.png","href":"http:\/\/www.mystore.com\/"}]}2=[{"text":"Buy#mystore","href":"http:\/\/www.mystore.com\/"}]3=1000025660978094=5070afefb42b162aff748f55ecf44d110d9e2a90117ee1704e2adb41f1d190fa
I have never done any development on Facebook SO I have no Idea what to do? Please help me with solution. & let me know if u guys need any other info to understand this.
Oh yeah One more thing the Client File code that is calling Api (call method) its like this
private function _prepareParams($method, $params)
{
$defaultParams = array(
'api_key' => $this->_apiKey,
'call_id' => microtime(true),
'format' => 'JSON',
'v' => '1.0'
);
if($this->_sessionKey){
$defaultParams['session_key'] = $this->_sessionKey;
}
$params = array_merge($defaultParams, $params);
foreach ($params as $key => &$val) {
if (!is_array($val)) continue;
$val = Zend_Json::encode($val);
}
$params['method'] = $method;
if(isset($params['sig'])) {
unset($params['sig']);
}
$params['sig'] = $this->_generateSig($params);
return $params;
}
public function call($method, $args=array())
{
Mage::log($args);
$params = $this->_prepareParams($method, $args);
$client = self::_getHttpClient()
->setUri(self::FACEBOOK_REST_URI)
->setMethod(Zend_Http_Client::POST)
->resetParameters()
->setParameterPost($params);
try {
$response = $client->request();
} catch(Exception $e) {
throw new Mage_Core_Exception('Service unavaliable');
}
if(!$response->isSuccessful()) {
throw new Mage_Core_Exception('Service unavaliable');
}
$result = Zend_Json::decode($response->getBody());
//json decode returns float on long uid number? is_json check? old php?
if(is_float($result)){
$result = $response->getBody();
}
if(is_array($result) && isset($result['error_code'])) {
throw new Mage_Core_Exception($result['error_msg'], $result['error_code']);
}
return $result;
}
For calling API I used two ways $this->_getClient()->call( 'facebook.stream.publish',
& $this->_getClient()->call( 'stream_publish',
None of them are working

Answer 1

ok GUys I figure out the mistake
look at my code
format=JSONv=1.01={"name":"mystore","href":"http:\/\/www.mystore.com\/","description":"New order on mystore.com","media":[{"type":"image","src":"http:\/\/www.mystore.com\/skin\/frontend\/default\/mystore\/images\/logo.png","href":"http:\/\/www.mystore.com\/"}]}2=[{"text":"Buy#mystore","href":"http:\/\/www.mystore.com\/"}]3=1000025660978094=5070afefb42b162aff748f55ecf44d110d9e2a90117ee1704e2adb41f1d190fa
where u can see format=JSONv=1.01={....}2=[{.....}] the problem was I used numeric arrays for parameters. they should be associated arrays
like message={new order}attachment={....}
Once I fixed the associative array problem my code start working correctly
here is a link that'll give u detail about parameters to pass to stream.publish
http://schoolout.net/en/developers/view/39
Hope this will help somebody else too.