[SOLVED] Check if URL Exists

[Omzy]

I've got a form which has a field to enter a URL, I've got basic preg_match to see if the URL is in a valid format, but I now want to also check that the URL actually exists on the Internet.

 

And optionally, can this be extended to check that the URL contains XML data, i.e. an RSS feed.

 

Thanks.

[MadTechie]

why not use $XML = file_get_contents($url); then valid the $XML with

$XML = file_get_contents($url);
if (preg_match('/^<\?xml/s', $XML))
{
echo "valid";
}

 

EDIT: of course this is a simple check but you can expand it to check the XML is a RSS feed

[Daniel0]

If you want to check that the page exist, just check that it returns a 200 status code.

[Omzy]

what about:

 

fopen($url, "r");

 

Is that sufficient?

[MadTechie]

Yes that would be fine

 

$handle = fopen($url, "r");
if($handle)
{
  $contents = fread($handle, 10);
  fclose($handle);
  if (preg_match('/^<\?xml/s', $contents))
  {
    echo "valid";
  }
}

 

EDIT: as a note i this will only read 10 bytes this is fine for checking its XML (infact 5 is okay) but not for checking its RSS

[Omzy]

Is there anything quicker than using fopen? It seems to take a long time for some sites and then eventually times out. I need something that will do a very quick check to see if the site is online, perhaps something that checks for header codes?

[Omzy]

Yes that would be fine

 

$handle = fopen($url, "r");
if($handle)
{
  $contents = fread($handle, 10);
  fclose($handle);
  if (preg_match('/^<?xml/s', $contents))
  {
    echo "valid";
  }
}

 

EDIT: as a note i this will only read 10 bytes this is fine for checking its XML (infact 5 is okay) but not for checking its RSS

 

How can I put all that code in to an ELSE IF statement?

[MadTechie]

Try this

 

<?php
$curl = curl_init();

$url = 'http://www.idontexist.co.uk'; //No domain
$url = 'http://www.google.co.uk'; //no RSS
$url = 'http://www.telegraph.co.uk/news/uknews/rss'; //valid

$valid = false;
curl_setopt($curl,CURLOPT_URL,$url);
curl_setopt($curl,CURLOPT_TIMEOUT, 5);
curl_setopt($curl, CURLOPT_HEADER, TRUE);
curl_setopt($curl, CURLOPT_FOLLOWLOCATION, FALSE);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, TRUE);
$result = curl_exec($curl);
$header = curl_getinfo($curl);
if ($header['http_code']=='200')
{
//echo "Found page<br>\n";
if(stripos($header['content_type'],'text/xml')!==false)
{
	//echo "Valid XML";
	$valid = true;
}
}
curl_close($curl);

if($valid)
{
//Blar
echo "$url will work";
}

?>?>

i have added 3 urls, for an example

Note the timeout is set to 5 seconds, if the server is slow then it may fail which a short timeout like that

 

[Omzy]

Cheers MadTechie I will also give that a try. Can you see if you can help with my query regarding your earlier code?

[MadTechie]

Sure, please note the last code i account for that, (note the last if statement)

 

for the other code a function would probably work best

ie

<?php
if(function urlExists('www.google.co.uk'))
{
echo "worked";
}


function urlExists($url)
{
$handle = fopen($url, "r");
if($handle)
{
  $contents = fread($handle, 10);
  fclose($handle);
  if (preg_match('/^<?xml/s', $contents))
  {
    return true;
  }
}
return false;
}
?>

[Omzy]

Cheers, that doesn't work though, it seems to be allowing invalid documents..

[MadTechie]

lol i'm a dumbarse

if(function urlExists('www.google.co.uk'))
{
echo "worked";
}

should be

if(urlExists('www.google.co.uk'))

{

echo "worked";

}

[Omzy]

LOL I saw that and fixed it. But I think there is a problem in the function, which is why it's not working for me..

 

Is it possible to assign a variable within an ELSE IF statment, for example:

 

instead of:

$handle = fopen($url, "r");

if($handle)

 

something like this:

else if($handle=fopen($url, "r"))

[DarkSuperHero]

if its a domain name you could use gethostbyname....

 

http://us3.php.net/manual/en/function.gethostbyname.php