Web crawling - php uses curl to crawl web pages

<code>封装了一个curl抓取网页的函数，在本地测没问题;放到测试服务器上后，如果通过浏览器访问
执行，大部分时候函数返回的HTTP状态码返回0，错误信息`Error:name lookup timed 
out`，极其偶像的情况下返回200成功;但如果直接在测试服务器上直接用命令行执行，100%成功。

代码如下：</code>

<code>static public function curlGet($url, $data = array(), $header = array(), $timeout = 3, $port = 80)
    {
        $is_ssl  = substr($url, 0, 5) == 'https' ? 1 : 0;

        $ch = curl_init();
        if (!empty($data)) {
            $data = is_array($data)?http_build_query($data): $data;
            $url .= (strpos($url,'?')?  '&': "?") . $data;
        }

        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'GET');
        curl_setopt($ch, CURLOPT_FOLLOWLOCATION,1); //是否抓取跳转后的页面
        curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 5);
        curl_setopt($ch, CURLOPT_TIMEOUT, $timeout);
        curl_setopt($ch, CURLOPT_POST, 0);
        //curl_setopt($ch, CURLOPT_PORT, $port);
        curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
        curl_setopt($ch, CURLOPT_REFERER, $url);
        // curl_setopt($ch, CURLOPT_USERAGENT, self::url2useragent($url));
        
        if($is_ssl){
            curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); // 跳过证书检查
            curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, true);  // 从证书中检查SSL加密算法是否存在
        }
        $result = array();
        $result['result'] = curl_exec($ch);
        $result['http_code'] = curl_getinfo($ch,CURLINFO_HTTP_CODE);
        if (0 != curl_errno($ch)) {
            $result['error']  = "Error:\n" . curl_error($ch);
        }
        curl_close($ch);
        return $result;
    }</code>

<code>我个人感觉和代码应该关系不大，不知是哪的问题。望各路大神不吝赐教，指点迷津，不胜
感激。</code>

Reply content:

<code>封装了一个curl抓取网页的函数，在本地测没问题;放到测试服务器上后，如果通过浏览器访问
执行，大部分时候函数返回的HTTP状态码返回0，错误信息`Error:name lookup timed 
out`，极其偶像的情况下返回200成功;但如果直接在测试服务器上直接用命令行执行，100%成功。

代码如下：</code>

<code>static public function curlGet($url, $data = array(), $header = array(), $timeout = 3, $port = 80)
    {
        $is_ssl  = substr($url, 0, 5) == 'https' ? 1 : 0;

        $ch = curl_init();
        if (!empty($data)) {
            $data = is_array($data)?http_build_query($data): $data;
            $url .= (strpos($url,'?')?  '&': "?") . $data;
        }

        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'GET');
        curl_setopt($ch, CURLOPT_FOLLOWLOCATION,1); //是否抓取跳转后的页面
        curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 5);
        curl_setopt($ch, CURLOPT_TIMEOUT, $timeout);
        curl_setopt($ch, CURLOPT_POST, 0);
        //curl_setopt($ch, CURLOPT_PORT, $port);
        curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
        curl_setopt($ch, CURLOPT_REFERER, $url);
        // curl_setopt($ch, CURLOPT_USERAGENT, self::url2useragent($url));
        
        if($is_ssl){
            curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); // 跳过证书检查
            curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, true);  // 从证书中检查SSL加密算法是否存在
        }
        $result = array();
        $result['result'] = curl_exec($ch);
        $result['http_code'] = curl_getinfo($ch,CURLINFO_HTTP_CODE);
        if (0 != curl_errno($ch)) {
            $result['error']  = "Error:\n" . curl_error($ch);
        }
        curl_close($ch);
        return $result;
    }</code>

<code>我个人感觉和代码应该关系不大，不知是哪的问题。望各路大神不吝赐教，指点迷津，不胜
感激。</code>

1. Set a larger timeout;
2. Restart the server;
3. Check whether the DNS is normal

Your server is having a seizure