Error PHP website crawler class using Simple HTML Dom - php

Question

I'm getting the following error when trying to use Simple HTML Dom inside a web crawler class. The class seems to be working well but I get many errors in my error_log file.
[01-Apr-2016 23:16:51 UTC] PHP Warning: Invalid argument supplied for foreach() in /home/scrybs/public_html/order/uploader/php/simple_html_dom.php on line 357
If I check Simple HTML Dom, the error comes from here:
function innertext()
{
if (isset($this->_[HDOM_INFO_INNER])) return $this->_[HDOM_INFO_INNER];
if (isset($this->_[HDOM_INFO_TEXT])) return $this->dom->restore_noise($this->_[HDOM_INFO_TEXT]);
$ret = '';
foreach ($this->nodes as $n)
$ret .= $n->outertext();
return $ret;
}
The crawler class in question is as following:
class crawler
{
protected $_url;
protected $_depth;
protected $_host;
protected $_useHttpAuth = false;
protected $_user;
protected $_pass;
protected $_seen = array();
protected $_filter = array();
public $contenu = array();
public function __construct($url, $depth = 5)
{
$this->_url = $url;
$this->_depth = $depth;
$parse = parse_url($url);
$this->_host = $parse['host'];
$this->html = new simple_html_dom();
}
protected function _processAnchors($content, $url, $depth)
{
//$dom = new DOMDocument('1.0');
//#$dom->loadHTML($content, LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD);
//$dom->formatOutput = true;
$this->html->load($content);
$metatitle = $this->html->find('title',0)->innertext;
foreach($this->html->find("meta[name='description']") as $element){
$metadescription = $element->content;
}
foreach($this->html->find("meta[name='keywords']") as $element){
$metakeywords = $element->content;
}
if(!empty($metatitle)){
$this->contenu['meta_titles'][] = $metatitle;
}
if(!empty($metadescription)){
$this->contenu['meta_titles'][] = $metadescription;
}
if(!empty($metakeywords)){
$this->contenu['meta_titles'][] = $metakeywords;
}
// IMAGE ALTS
foreach($this->html->find('img') as $e){
if(!empty($e->alt)){
if(!$this->search_array($e->alt, $this->contenu)){
$this->contenu['alt_images'][] = $e->alt;
}
}
}
// LINKS
$links = $this->html->find('a');
foreach($links as $element){
// GET LINK TEXTS
$a = $element->innertext;
$a = preg_replace("/<a.*?>(.*?)<\/a>/", '\1', $a);
$a = preg_replace("/<p.*?>.*?<\/p>/", "{{P}}", $a);
$a = preg_replace("/<img.*?>/", "{{IMG}}", $a);
$a = preg_replace('#(<br */?>\s*)+#i', "{{BR}}", $a);
$a = preg_replace('#<button.*?>.*?</button>#i', '{{BUTTON}}', $a);
$a = preg_replace('#<time.*?>(.*?)</time>#i', '{{TIME}}', $a);
$a = preg_replace('#<span.*?>(.*?)</span>#i', '{{SPAN}}\1{{/SPAN}}', $a);
$a = preg_replace('#<strong.*?>(.*?)</strong>#i', '{{STRONG}}\1{{/STRONG}}', $a);
$a = preg_replace('#<b.*?>(.*?)</b>#i', '{{B}}\1{{/B}}', $a);
$a = preg_replace('#<i.*?>(.*?)</i>#i', '{{I}}\1{{/I}}', $a);
$a = preg_replace('#<small.*?>(.*?)</small>#i', '{{SMALL}}\1{{/SMALL}}', $a);
$a = preg_replace('#<abbr.*?>(.*?)</abbr>#i', '{{ABBR}}\1{{/ABBR}}', $a);
$a = trim(strip_tags($a));
$a = preg_replace('/\s+/', ' ', $a);
// CHECK IF NOT ONLY VARIABLES AND SPACES
$atmp = strip_tags($a);
$atmp = preg_replace("/{{.*?}}/", '', $atmp);
$atmp = preg_replace('/\s+/', '', $atmp);
if(!empty($a) && $a != '' && $atmp != ''){
if(!$this->search_array($a, $this->contenu)){
$this->contenu['link_texts'][] = $a;
}
}
// GET LINK TITLES
$title = $element->title;
if(!empty($title)){
if(!$this->search_array($title, $this->contenu)){
$this->contenu['link_titles'][] = $title;
}
}
$href = $element->href;
if (0 !== strpos($href, 'http')) {
$path = '/' . ltrim($href, '/');
if (extension_loaded('http')) {
$href = http_build_url($url, array('path' => $path));
} else {
$parts = parse_url($url);
$href = $parts['scheme'] . '://';
if (isset($parts['user']) && isset($parts['pass'])) {
$href .= $parts['user'] . ':' . $parts['pass'] . '#';
}
$href .= $parts['host'];
if (isset($parts['port'])) {
$href .= ':' . $parts['port'];
}
$href .= $path;
}
}
// Crawl only link that belongs to the start domain
$this->crawl_page($href, $depth - 1);
}
return $this->contenu;
}
protected function _getContent($url)
{
$handle = curl_init($url);
if ($this->_useHttpAuth) {
curl_setopt($handle, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
curl_setopt($handle, CURLOPT_USERPWD, $this->_user . ":" . $this->_pass);
}
// follows 302 redirect, creates problem wiht authentication
// curl_setopt($handle, CURLOPT_FOLLOWLOCATION, TRUE);
// return the content
curl_setopt($handle, CURLOPT_RETURNTRANSFER, TRUE);
/* Get the HTML or whatever is linked in $url. */
$response = curl_exec($handle);
// response total time
$time = curl_getinfo($handle, CURLINFO_TOTAL_TIME);
/* Check for 404 (file not found). */
$httpCode = curl_getinfo($handle, CURLINFO_HTTP_CODE);
curl_close($handle);
return array($response, $httpCode, $time);
}
protected function _printResult($url, $depth, $httpcode, $time)
{
ob_end_flush();
$currentDepth = $this->_depth - $depth;
$count = count($this->_seen);
//echo "N::$count,CODE::$httpcode,TIME::$time,DEPTH::$currentDepth URL::$url <br>";
ob_start();
flush();
}
protected function isValid($url, $depth)
{
if (strpos($url, $this->_host) === false
|| $depth === 0
|| isset($this->_seen[$url])
|| preg_match("/#/i", $url)
|| preg_match("/.png/i", $url)
|| preg_match("/.jpg/i", $url)
|| preg_match("/.jpeg/i", $url)
|| preg_match("/.gif/i", $url)
|| preg_match("/.pdf/i", $url)
|| preg_match("/javascript/i", $url)
|| preg_match("/twitter.com/i", $url)
|| preg_match("/google.com/i", $url)
|| preg_match("/facebook.com/i", $url)
|| preg_match("/youtube.com/i", $url)
|| preg_match("/instagram.com/i", $url)
|| preg_match("/wp-login.php/i", $url)
) {
return false;
}
foreach ($this->_filter as $excludePath) {
if (strpos($url, $excludePath) !== false) {
return false;
}
}
return true;
}
public function search_array($needle, $haystack) {
if(in_array($needle, $haystack)) {
return true;
}
foreach($haystack as $element) {
if(is_array($element) && $this->search_array($needle, $element))
return true;
}
return false;
}
public function crawl_page($url, $depth)
{
if (!$this->isValid($url, $depth)) {
return;
}
// add to the seen URL
$this->_seen[$url] = true;
// get Content and Return Code
list($content, $httpcode, $time) = $this->_getContent($url);
// print Result for current Page
//$this->_printResult($url, $depth, $httpcode, $time);
// process subPages
$this->_processAnchors($content, $url, $depth, $contenu = array());
}
public function addFilterPath($path)
{
$this->_filter[] = $path;
}
public function run()
{
$this->crawl_page($this->_url, $this->_depth);
}
}
The error seems to be coming from this line related to innertext function:
// GET LINK TEXTS
$a = $element->innertext;
I don't get any error when I use:
$a = $element->innertext;
But not ideal as I would like to keep HTML tags. I don't get any error when I use Simple HTML Dom outside the class so does it have something to do with the fact that Simple HTML Dom is in a class? Do somebody have an idea?
Thanks for your help!

Answer 1

I have found the bug.
On my (limited) tests, the problem happens when you set depth > 1, so — seeing your code — when you load more than one page URL. One of the countless Simple HTML DOM problems, is that ->load() method doesn't work correctly on multiple loads.
Re-instantiating html object, the script seems work:
protected function _processAnchors( $content, $url, $depth )
{
$this->html = new simple_html_dom(); # <-----
$this->html->load( $content );
I tested also $this->html = str_get_html($content); but it works only on limited sites.
Additional Note: In HTML <title> tag is mandatory, but not all sites has well formatted HTML: consider checking for <title> tag (and for each tag) existence to avoid additional errors.