How to validate urls?

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I am writing a link exchange script, and I would like to check if the URLs that people submit are valid.

Can you give me an idea how to do this?

Thanks in advance.

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try this function:

Code:

<?php
function check_url($url) {
$url_parts = parse_url($url);
if (array_key_exists("host", $url_parts)) {
$insert_url = $url_parts['host'];
$tested_host = gethostbyname($this->insert_url);
if ($tested_host <> $insert_url) {
return true;
} else {
return false;
}
} else {
return false;
}
}

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Wow that's great. Thanks

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Wow that's great. Thanks

It's a part of my own link exchange script

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and use some regex first:

Code:

<?php 
if (preg_match("/^http\:\/\/[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(\S*)?$/i", $url)) {
  //
}

otherwise it takes some time until the error is collected

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BTW here is a version to use outside a class, with error reporting = on :

Code:

<?php
function check_url($url) 
{
if (preg_match("/^http\:\/\/[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(\S*)?$/i", $url))
{
$url_parts = @parse_url($url);
if (@array_key_exists("host", $url_parts)) 
{
$insert_url = $url_parts['host'];
$tested_host = gethostbyname($url);
if ($tested_host <> $insert_url)
return true;
else
return false;
} else {
return false;
}
}else
return false;
 }

Thanks again

Check a url is live with socket (more secure)

Code:

<?php
function check_url_is_live($url) 
{
  if(($ar=parse_url($url)) && ($fp=@fsockopen($ar[host],80,$errno,$errstr,2))) 
  { 
     fclose($fp);
     return true;
  }
  else
     return false;
}
?>

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@thek,

I saw this  method before but how about speed, and if the given host was redirected. And why is this moresecure please explain?

An what if the site is really busy then is an existing URL = false.

but there are many ways to rome

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What about CURL?

I guess it would be also faster than socket

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Yes Curl is the power 

but again to validate an existing URL the first function is enough, only if you need to know that a URL is active you have to open the remote URL.

Function curl execute php stream...
Php stream use socket for url opening...
So socket is more advanced than curl!

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Function curl execute php stream...
Php stream use socket for url opening...
So socket is more advanced than curl!

But opening the file to check if the url is valid is like shooting with canon balls on little chicken...

Only open a connection, like ping...
No read file data...
If ulr is down, wait only 2 seconds...

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Thanks for the help guys.

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