/**
 * @param $url
 * @param string $error
 * @param array|string $post
 * @param int $timeout
 * @param null $ref
 * @param string $ua
 * @param $contentType
 * @return bool|mixed
 */
function xcurl($url, &$error = "", $post = array(), $timeout = 5, $ref = null, $ua = "Mozilla/5.0 (X11; Linux x86_64; rv:2.2a1pre) Gecko/20110324 Firefox/4.2a1pre", $contentType) {
    $ch           = curl_init();

    if(!empty($ref)) {
        curl_setopt($ch, CURLOPT_REFERER, $ref);
    }

    curl_setopt($ch, CURLOPT_AUTOREFERER, true);
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
    curl_setopt($ch, CURLOPT_TIMEOUT, $timeout);

    if (false !== stripos($url, "https://")) {                # https处理，不校验相关证书
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);
    }

    if(!empty($ua)) {
        curl_setopt($ch, CURLOPT_USERAGENT, $ua);
    }

    if(count($post) > 0){
        curl_setopt($ch, CURLOPT_POST, 1);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $post);
    }

    if ('json' == $contentType) {
        curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/json', 'Content-Length: ' . strlen($post)));
    }

    $output       = curl_exec($ch);
    if ($output === false) {
        $error    = curl_error($ch);
        curl_close($ch);
        return false;
    } else {
        curl_close($ch);
        return $output;
    }
}