Php backlink checker on another website - php

Question

I am trying to make a script to check if a webpage has a back link to my page. I have found this script but the problem is that it returns the error message "No back link found" even if there is a backlink. Could someone tell me what is wrong with this script?
Here is the script I am using:
require('simple_html_dom.php');
function CheckReciprocal( $targetUrl, $checkLinkUrl, $checkNofollow = true )
{
$html = file_get_html($targetUrl);
if (empty($html))
{
//# Could not load file
return false;
}
$link = $html->find('a[href^='.$checkLinkUrl.']',0);
if (empty($link))
{
//# Link not found
return false;
}
if ( $checkNofollow && $link->hasAttribute('rel') )
{
$attr = $link->getAttribute('rel');
return (preg_match("/\bnofollow\b/is", $attr) ? false : true);
}
return true;
}
$targetUrl = 'http://example.com/test.html';
$checkLinkUrl = 'http://mysite.com';
if ( CheckReciprocal($test, $checkLinkUrl) )
{
echo 'Link found';
}
else { echo 'Link not found or marked as nofollow'; }
Thank you!

Answer 1

I don't know how does that simple_html_dom.php's $html->find() works cos never used it, but it seems that your problem is there. I would trust the good ol' DOMDocument + regex.
Just wrote a function and tested it, just use on the $url the plain domain + whatever you want, don't worry about the http(s) or www and stuff like that:
function checkBackLink($link, $url, $checkNoFollow = true){
$dom = new DOMDocument();
$dom->loadHTMLFile($link);
foreach($dom->getElementsByTagName('a') as $item){
if($checkNoFollow){
if(preg_match('/nofollow/is', $item->getAttribute('rel'))) continue;
}
if($item->hasAttribute('href') === false) continue;
if(preg_match("#^(https?\://)?(www\.)?$url.*#i", $item->getAttribute('href'))) return true;
}
}
if(checkBacklink('the link', 'example.com')){
echo "link found";
} else {
echo "Link not found or marked as nofollow";
}
If you don't like it and still want to use the simple_html_dom just make sure how that find() works, because if it only match exact values that could be troublesome.