Question

如果没有重定向的URL，我的getRedirect()将失败。但是我想检查数组中的URL。

function getRedirect($url) {
        $ch = curl_init($url);
        curl_setopt($ch, CURLOPT_HEADER, false);
        curl_setopt($ch, CURLOPT_USERAGENT,'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.13) Gecko/20080311 Firefox/2.0.0.13');
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
        curl_setopt($ch, CURLOPT_BINARYTRANSFER, true);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($ch, CURLOPT_CONNECTTIMEOUT ,0);
        curl_setopt($ch, CURLOPT_TIMEOUT, 60);
        $data = curl_exec($ch);
        $domd=@\DOMDocument::loadHTML($data);
        $xp=new \DOMXPath($domd);

        $location=$xp->query("//meta[@http-equiv='REFRESH']")->item(0)->getAttribute("content");
        $location=substr($location,stripos($location,'URL=')+4);

        curl_close($ch);

        return $location;
    }

错误说：Call to a member function getAttribute() on null

我尝试了以下类似操作，但没有帮助。

   if ($location=$xp->query("//meta[@http-equiv='REFRESH']")->item(0)->getAttribute("content") !== false) {
            $location=substr($location,stripos($location,'URL=')+4);
            curl_close($ch);
            return $location;
        } else {
            return true;
        }

如果所有URL都被重定向，则函数起作用。我该如何解决这个问题？

Answer 1

在假定存在任何匹配元素之前，应检查XPath query()结果的length

例如

curl_close($ch); // this can go immediately after curl_exec()

$metaTags = $xp->query("//meta[@http-equiv='REFRESH']");
if ($metaTags->length > 0) {
    $location = $metaTags->item(0)->getAttribute('content');
    return substr($location, stripos($location,'URL=') + 4);
} 
return true; // or return whatever makes sense if there's no `<meta>` tag

如果没有重定向URL，重定向功能将失败

1 个答案: