在PHP中,我如何阅读不可靠的网页?

I'm trying to use Curl in PHP to read a unreliable web page. The page is often unavailable because of server errors. However, I still need to read it if it's available. Additionally, I don't want the unreliability of the web page to effect my code. I would like my PHP to fail gracefully and move on. Here is what I have so far:

<?php
    function get_url_contents($url){
        $crl = curl_init();
        $timeout = 2;
        curl_setopt ($crl, CURLOPT_URL,$url);
        curl_setopt ($crl, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt ($crl, CURLOPT_CONNECTTIMEOUT, $timeout);
        $ret = curl_exec($crl);
        curl_close($crl);
        return $ret;
    }
    $handle = get_url_contents ( 'http://www.mydomain.com/mypage.html' );
?>

You could test the HTTP code to see if the page was successfully retrieved by testing the HTTP Response code. I can't remember if >200 and <302 are the correct code ranges though, have a quick peak at http response codes If you use this method.

<?php
    function get_url_contents($url){
        $crl = curl_init();
        $timeout = 2;
        curl_setopt ($crl, CURLOPT_URL,$url);
        curl_setopt ($crl, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt ($crl, CURLOPT_CONNECTTIMEOUT, $timeout);
        $ret['pagesource'] = curl_exec($crl);
        $httpcode = curl_getinfo($crl, CURLINFO_HTTP_CODE);
        curl_close($crl);

        if($httpcode >=200 && $httpcode<302) {
         $ret['response']=true;
        } else {
         $ret['response']=false;
        }

        return $ret;
    }
    $handle = get_url_contents ( 'http://192.168.1.118/newTest/mainBoss.php' );
    if($handle['response']==false){
          echo 'page is no good';
    } else {
             echo 'page is ok and here it is:' . $handle['pagesource'] . 'DONE.<br>';
    }

?>

Use this instead, CURL is not super recommanded anymore as i've heard since PHP wrappers offer much better performance and are always available anywhere you go:

$currentcontext = stream_context_get_default();
stream_context_set_default(stream_context_create(array('timeout' => 2)));
$content = file_get_contents('url', $context);
stream_context_set_default($currentcontext);

This will set the default stream context to timeout after 2 seconds and get the content of the url via a stream wrapper that should be there in all php versions from 5.2 and up for sure;

You are not obligated to restore the default context depending on your site's code but it's always a good thing to do. If you don't, then this operation can be achieved in only 2 lines of code...