Jan 20 2010

New version of Mini Bots PHP Class (v.1.4)

Category: Php,Spiders & web bots — Giulio Pons @ 11:53 pm

I’ve added three more bots to the Mini Bots Php Class, now the version number is 1.4 and it has these new features.

Follow the link, watch demos and download the class from the Mini Bots Php Class page:

  1. addeded twitterInfo method to retrieve the numbers of following, followers, and lists.
  2. addeded url2pdf method to convert and save locally a page to a pdf (thanks to pdfmyurl.com service).
  3. addeded webpage2txt method to extract all the text from a url, stripping html but also scripts and styles.

What else do you need? Suggest some usefull small bots. Comment to suggest.

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Jan 16 2010

PHP Web page to text function

Category: Php,Spiders & web bots — Giulio Pons @ 2:55 pm

I’ve found this nice small bot on the www.php.net site, thanks to the author of the script on the preg_replace page.
This bot returns the text content of a url and it could be used to take text from a site and find relevant words to search.

It’s nice because it uses CURL and let us see some nice stuff that CURL does:

  1. hide himself presenting with a specific user agent, to seem a browser and not a spider
  2. follows redirect (this means that you can call this function with a tiny url to retrieve the text in the real page!)
  3. use very powerful regular expression to remove html tags, but also javascript and styles (they remain if you simply do a strip_tags)

This script will be included in the next version of the Mini Bots PHP Class.

function webpage2txt($url) {
	$user_agent = "Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)";

	$ch = curl_init();    // initialize curl handle
	curl_setopt($ch, CURLOPT_URL, $url); // set url to post to
	curl_setopt($ch, CURLOPT_FAILONERROR, 1);              // Fail on errors
	curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);    // allow redirects
	curl_setopt($ch, CURLOPT_RETURNTRANSFER,1); // return into a variable
	curl_setopt($ch, CURLOPT_PORT, 80);            //Set the port number
	curl_setopt($ch, CURLOPT_TIMEOUT, 15); // times out after 15s

	curl_setopt($ch, CURLOPT_USERAGENT, $user_agent);

	$document = curl_exec($ch);

	$search = array('@<script[^>]*?>.*?</script>@si',  // Strip out javascript
		'@<style[^>]*?>.*?</style>@siU',    // Strip style tags properly
		'@<[\/\!]*?[^<>]*?>@si',            // Strip out HTML tags
		'@<![\s\S]*?–[ \t\n\r]*>@',         // Strip multi-line comments including CDATA
		'/\s{2,}/',
	);

	$text = preg_replace($search, "\n", html_entity_decode($document));

	$pat[0] = "/^\s+/";
	$pat[2] = "/\s+\$/";
	$rep[0] = "";
	$rep[2] = " ";

	$text = preg_replace($pat, $rep, trim($text));

	return $text;
}

echo webpage2txt("http://www.rockit.it");
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Jan 06 2010

Test if a remote url exists with PHP and CURL

Category: Php,Spiders & web bots — Giulio Pons @ 10:13 am

If you have to test if a local file exists you will probably use the php file_exists function, but if you have to test a remote file, that is to say a remote url, than you can use CURL and get the headers returned by the http request. If you receive a 200 code, than it’s ok, else the url is not correct.

This function is included in the Mini Bots Class.

function url_exists($url) {
	$ch = @curl_init($url);
	@curl_setopt($ch, CURLOPT_HEADER, TRUE);
	@curl_setopt($ch, CURLOPT_NOBODY, TRUE);
	@curl_setopt($ch, CURLOPT_FOLLOWLOCATION, FALSE);
	@curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
	$status = array();
	preg_match('/HTTP\/.* ([0-9]+) .*/', @curl_exec($ch) , $status);
	return ($status[1] == 200);
}

If you you don’t have CURL lib istalled you can use the php get_headers function, it returns an array with the headers:

$url = 'http://www.example.com';
print_r(get_headers($url));
print_r(get_headers($url, 1));

If you apply the preg_match function to the first element of the array you will reach the same result:

function url_exists($url) {
	$h = get_headers($url);
	$status = array();
	preg_match('/HTTP\/.* ([0-9]+) .*/', $h[0] , $status);
	return ($status[1] == 200);
}
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