php怎麼使用curl傳輸檔案流

public function postFile(){   $name = 'filename';   $path = './Resource/temp_pdf/';   $ext = '.pdf';

   if (is_file($path . $name . $ext) && filesize($path . $name . $ext) != 0) {      $url = "http://test.api.com/index.php";      $post_data = array(         "foo" => "bar",         //@代表此欄位屬於檔案，接收方只需用$_FILES便可接收檔案         "upload" => '@' . $path . $name . $ext,      );      $res = httpRequest($url,$post_data);      var_dump($res);      //TODO::擷取返回資料的動作   }}

/** * 請求遠程地址 * * @param string $url 請求url * @param mixed $postFields 請求的資料 * @param string $referer 來源網址 * @param integer $timeOut 請求逾時時間 * @param array $header 頭部檔案 * @return mixed 錯誤返回false，正確返回擷取的字串 * @author fengxu */function httpRequest($url, $postFields = null, $referer = null, $timeOut = 300, $header = null){    if (empty($url) || !preg_match("#https?://[\w@\#$%*&=+-?;:,./]+#i", $url)) {        return false;    }    $isPost = empty($postFields) ? false : true;    $ch = curl_init();    if (is_null($header)) {        $header = array(            'Pragma' => 'no-cache',            'Accept' => 'text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,q=0.5',            'User-Agent' => 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.82 Safari/537.36',        );    }    $headers = array();    foreach ($header as $k => $v) {        $headers[] = $k . ': ' . $v;    }    curl_setopt($ch, CURLOPT_URL, $url);    if ($isPost) {        //$postFields = http_build_query($postFields);        curl_setopt($ch, CURLOPT_POST, true);        curl_setopt($ch, CURLOPT_POSTFIELDS, $postFields);    }    curl_setopt($ch, CURLOPT_TIMEOUT, $timeOut);    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 0);    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);    curl_setopt($ch, CURLOPT_HEADER, 0);    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);    curl_setopt($ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_0);    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);    $response = curl_exec($ch);    if ($response === false) {        throw new Exception(curl_error($ch), '500');    }    return $response;}