CURL在不同时间为同一页返回响应代码200和0 [英] CURL returns response code 200 and 0 for a same page at different time

问题描述

我面临一个不寻常的卷曲行为。对于给定的页面，我有时获得HTTP响应代码为200，有时我获得0作为HTTP响应代码。我无法理解此网页是否有效。如果你尝试给定的代码，请尝试至少5-10次，以便你可以看到差异。

I am facing one unusual behavior of curl. For a given page, I some times get HTTP response code as 200 and sometimes I get 0 as HTTP response code. I am not able to understand whether this page is valid or not. If you try the given code, please try it for at least 5-10 times so that you can see the difference.

function print_info()
{
    $url = 'bart.no';
    $arr = array(
    'bart.no',
    'bolandirekt.nu',
    'ekompassen.com',
    'ekompassen.nu',
    );

    foreach ($arr as $url)
    {
        echo "<br/>URL: " . $url;
        $temp = str_replace(array("www.", "http://", "https://"), "", strtolower($url));

        // From this array it will be decided which is to prepend
        $pre_array = array("", "www.", "https://", "http://", "https://www.", "http://www.");
        $status_code = array();

        // For each Value Status will be stored
        foreach ($pre_array as $pre)
        {

            $options = array(
                CURLOPT_RETURNTRANSFER => TRUE, // return web page
                CURLOPT_HEADER => TRUE, // don't return headers
                CURLOPT_FOLLOWLOCATION => FALSE, // follow redirects
                CURLOPT_ENCODING => "", // handle all encodings
                CURLOPT_USERAGENT => "spider", // who am i
                CURLOPT_AUTOREFERER => FALSE, // set referer on redirect
                CURLOPT_SSL_VERIFYHOST => FALSE, //ssl verify host
                CURLOPT_SSL_VERIFYPEER => FALSE, //ssl verify peer
                CURLOPT_NOBODY => FALSE,
                CURLOPT_CONNECTTIMEOUT => 20, // timeout on connect
                CURLOPT_TIMEOUT => 20, // timeout on response
            );

            // Initializing Curl
            $ch = curl_init($pre . $temp);
            // Set Curl Options
            curl_setopt_array($ch, $options);
            // Execute Curl
            $content = curl_exec($ch);

            $code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
            echo "<pre/>";
            if ($code == 200)
            {
                print_r(curl_getinfo($ch));
                break;
            }           
                            curl_close($ch);
        }
    }
}

<为什么我的响应代码为200，为不存在或不打开浏览器的网页？此外，为什么有时候我会得到响应代码0和有时响应代码200为同一页，即使我保持请求之间的时间间隔。

So my final doubt is : Why I am getting response code 200 for the pages which are not existing Or not opening in browser ? Also, why sometimes I get response code 0 and sometimes response code 200 for the same page even if I keep time interval between requests ?

推荐答案

CURL请求没有完成，因此没有响应代码。
此原因可能是无效的主机名（无法解析），格式不正确的网址，超时等。

The CURL request did not complete, thus there's no response code. The reason for this may be an invalid host name (can't resolve), malformed URL, timeout, etc.

您应该能够CURL错误代码，如CodeCaster的注释和curl_error / curl_errno文档。

You should be able to get the CURL error code as in CodeCaster's comment and curl_error / curl_errno docs.

一旦CURL请求正确完成，响应代码（从服务器）应该可用和有意义。

Once the CURL request completed properly, then a response code (from the server) should be available and meaningful.

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