Question

I have this code:

<?php
$url = "http://asdsfsfsfsfsdfad.com";
$file = file_get_contents($url);

if(preg_match("/<title>(.+)<\/title>/i",$file,$m))
    print "$m[1]";
else
    print "The page doesn't have a title tag";
?>

It works fine when the url is a proper url, but when I put in nonsense then I get two warning messages:

Warning: file_get_contents() [function.file-get-contents]: php_network_getaddresses: getaddrinfo failed: Navn eller tjeneste ukendt in /var/www/web17/web/administration/custom_pages.php(71) : eval()'d code on line 4
Warning: file_get_contents(http://asdsfsfsfsfsdfad.com) [function.file-get-contents]: failed to open stream: php_network_getaddresses: getaddrinfo failed: Navn eller tjeneste ukendt in /var/www/web17/web/administration/custom_pages.php(71) : eval()'d code on line 4

Any way to prevent this?

Answer 1

The easiest solution would be to just suppress the error:

echo @file_get_contents("http://asdsfsfsfsfsdfad.com");

However, error suppression is generally considered bad practise because you never know what went wrong, so it is better to have a handler that selectively handles errors, for instance

set_error_handler(function($code, $message) {
    return ($code === E_WARNING && strpos($message, 'php_network_getaddresses'));
});
echo file_get_contents("http://asdsfsfsfsfsdfad.com");

This would suppress any E_WARNINGS with a message containing ‘php_network_getaddresses’. Any other Warnings will not be suppressed.

In addition, you dont want Regex to parse HTML, but use an HTML Parser, like one of those given in

• How do you parse and process HTML/XML in PHP?

So you could do it with DOM. Again, either using Error Suppression (bad)

$dom = new DOMDocument;
@$dom->loadHTMLFile("http://asdsfsfsfsfsdfad.com");
$titles = $dom->getElementsByTagName('title');
echo $titles->length ? $dom->nodeValue : 'No Title found';

Or selectively suppressing network errors:

set_error_handler(function($code, $message) {
    return ($code === E_WARNING && strpos($message, 'php_network_getaddresses'));
});

$dom = new DOMDocument;
$dom->loadHTMLFile("http://asdsfsfsfsfsdfad.com");
$titles = $dom->getElementsByTagName('title');
echo $titles->length ? $titles->item(0)->nodeValue  : 'No Title found';

However, this will then result in parsing errors because loadHTMLFile will not return any HTML, so to suppress the parsing errors as well, you’d have to do:

set_error_handler(function($code, $message) {
    return ($code === E_WARNING && strpos($message, 'php_network_getaddresses'));
});
libxml_use_internal_errors(true);
$dom = new DOMDocument;
$dom->loadHTMLFile("http://asdsfsfsfsfsdfad.com");
libxml_clear_errors();
$titles = $dom->getElementsByTagName('title');
echo $titles->length ? $titles->item(0)->nodeValue : 'No Title found';