Warnings when file_get_content wrong url - php

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';

Answer 2

implode() expects the second parmeter to be an array, thus, check if $file is an array before doing an implode.
$file = is_array($file) ? implode("",$file) : $file;
Or even better, use file_get_contents, then you won't need to use implode:
$url = "http://asdsfsfsfsfsdfad.com";
$file = file_get_contents($url);

Answer 3

You should check the $file value for false before joining:
$url = "http://asdsfsfsfsfsdfad.com";
$file = file($url);
if ($file !== false) {
$file = implode("",$file);
if(preg_match("/<title>(.+)<\/title>/i",$file,$m)) {
print "$m[1]";
} else {
print "The page doesn't have a title tag";
}
} else {
print "wrong url";
}

Answer 4

you can check whether $file is array or not ..
if you check it then it will never give you an error..
if(is_array($file) && count($file)>0){
if(preg_match("/<title>(.+)<\/title>/i",$file,$m))
print "$m[1]";
else
print "The page doesn't have a title tag";
}
else{
echo "$file is not arrya so it does not go in the fi block.";
}

Answer 5

You don't need to add the quotes around the file contents string. When you use the function file_get_contents, it already returns the results as a string. By adding those double quotes around it, you are basically adding nothing to the string.

Answer 6

You can use curl to check if the url is valid:
<?
function url_exists($strURL) {
$resURL = curl_init();
curl_setopt($resURL, CURLOPT_URL, $strURL);
curl_setopt($resURL, CURLOPT_BINARYTRANSFER, 1);
curl_setopt($resURL, CURLOPT_HEADERFUNCTION, 'curlHeaderCallback');
curl_setopt($resURL, CURLOPT_FAILONERROR, 1);
curl_exec ($resURL);
$intReturnCode = curl_getinfo($resURL, CURLINFO_HTTP_CODE);
curl_close ($resURL);
if ($intReturnCode != 200 && $intReturnCode != 302 && $intReturnCode != 304) {
return false;
}Else{
return true ;
}
}
//Usage Example :
If(url_exists("http://www.weberdev.com/addexample.php3")) {
Echo"URL Exists";
}Else{
Echo"URL doesnot exist";
}
?>
See http://www.weberdev.com/get_example.php3?ExampleID=4335 for more information.