PHP simple HTML DOM parser errors - php

Question

I've started writing a scraper for one site that will also have a crawler, since I need to go through some links, but I'm getting this error :
PHP Fatal error: Uncaught Error: Call to a member function find() on
null in D:\Projekti\hemrank\simple_html_dom.php:1129 Stack trace:
0 D:\Projekti\hemrank\scrapeit.php(37): simple_html_dom->find('ul')
1 D:\Projekti\hemrank\scrapeit.php(19): ScrapeIt->getAllAddresses()
2 D:\Projekti\hemrank\scrapeit.php(55): ScrapeIt->run()
3 {main} thrown in D:\Projekti\hemrank\simple_html_dom.php on line 1129
When I var_dump the $html variable I get the full html with all the tags, etc, that's why it's strange to me that it says "Call to a member function find() on null", when there's actually value in the $html. Here's the part of the code that's not working :
$html = new simple_html_dom();
$html->load_file($baseurl);
if(empty($html)){echo "HTTP Response not received!<br/>\n";exit;}
$links = array();
foreach ($html->find('ul') as $ul) {
if(!empty($ul) && (count($ul)>0))
foreach ($ul->find('li') as $li) {
if(!empty($li) && (count($li)>0))
foreach ($li->find('a') as $a) {
$links[] = $a->href;
}
else
die("NOT AVAILABLE");
}
}
return $links;
}
Is this a common problem with PHP simple HTML DOM parser, is there a solution or should I switch to some other kind of scraping?

Answer 1

I just searched for the lib you are using, this is line 1129:
return $this->root->find($selector, $idx, $lowercase);
So your error message is telling you that $this->root inside the class is null, therefore no find() method exists!
I'm no expert on the lib, as I use the awesome DOMDocument for parsing HTML, but hopefully this should help you understand what has happened.
Also, $html will never be empty in that code of yours, you already populated it when you instantiated it!

Answer 2

I suggest the following change:
$html->load_file($baseurl); to $html = file_get_html($baseurl);
On my VPS server it works with $html->load_file($baseurl); but on my dedicated local server it only works with $html = file_get_html($baseurl);
This solved my problem:
- Call to a member function find() on null
- simple_html_dom.php on line 1129