another twitter oAuth cURL access token request that fails

Below is what Ive put together so far and it works :-)

    class Twitauth    {      var $key = '';      var $secret = '';      var $request_token = "https://twitter.com/oauth/request_token";    function Twitauth($config)    {        $this->key = $config['key']; // consumer key from twitter        $this->secret = $config['secret']; // secret from twitter    }    function getRequestToken()    {        // Default params        $params = array(            "oauth_version" => "1.0",            "oauth_nonce" => time(),            "oauth_timestamp" => time(),            "oauth_consumer_key" => $this->key,            "oauth_signature_method" => "HMAC-SHA1"         );         // BUILD SIGNATURE            // encode params keys, values, join and then sort.            $keys = $this->_urlencode_rfc3986(array_keys($params));            $values = $this->_urlencode_rfc3986(array_values($params));            $params = array_combine($keys, $values);            uksort($params, 'strcmp');            // convert params to string             foreach ($params as $k => $v) {$pairs[] = $this->_urlencode_rfc3986($k).'='.$this->_urlencode_rfc3986($v);}            $concatenatedParams = implode('&', $pairs);            // form base string (first key)            $baseString= "GET&".$this->_urlencode_rfc3986($this->request_token)."&".$this->_urlencode_rfc3986($concatenatedParams);            // form secret (second key)            $secret = $this->_urlencode_rfc3986($this->secret)."&";            // make signature and append to params            $params['oauth_signature'] = $this->_urlencode_rfc3986(base64_encode(hash_hmac('sha1', $baseString, $secret, TRUE)));         // BUILD URL            // Resort            uksort($params, 'strcmp');            // convert params to string             foreach ($params as $k => $v) {$urlPairs[] = $k."=".$v;}            $concatenatedUrlParams = implode('&', $urlPairs);            // form url            $url = $this->request_token."?".$concatenatedUrlParams;         // Send to cURL         print $this->_http($url);              }    function _http($url, $post_data = null)    {               $ch = curl_init();        curl_setopt($ch, CURLOPT_URL, $url);        curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 30);        curl_setopt($ch, CURLOPT_TIMEOUT, 30);        curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);        if(isset($post_data))        {            curl_setopt($ch, CURLOPT_POST, 1);            curl_setopt($ch, CURLOPT_POSTFIELDS, $post_data);        }        $response = curl_exec($ch);        $this->http_status = curl_getinfo($ch, CURLINFO_HTTP_CODE);        $this->last_api_call = $url;        curl_close($ch);        return $response;    }    function _urlencode_rfc3986($input)    {        if (is_array($input)) {            return array_map(array('Twitauth', '_urlencode_rfc3986'), $input);        }        else if (is_scalar($input)) {            return str_replace('+',' ',str_replace('%7E', '~', rawurlencode($input)));        }        else{            return '';        }    }}

not sure if your still looking into this, or if it will work for you, but i had a similar setup and had the same issue. I eventually found i was urlencoding one to many times.Try commenting out this section:

 $keys = $this->_urlencode_rfc3986(array_keys($params));        $values = $this->_urlencode_rfc3986(array_values($params));        $params = array_combine($keys, $values);

Worked for me, so maybe it will help.

I'll admit this isn't really an answer, but if you can, use the PECL OAuth package. Rasmus Lerdorf wrote a tutorial on how to use it and it got me around this same issue.