Regex / preg_match_all help needed

middleman666

Hi All,

Having a bit of a nightmare getting this script to work as intended so wondered if anyone could shed some light on what's going on...

Basically, I have html stored in a variable $Template which contains text links and forms. I'm trying to search through that html and append a few variables onto the href and action attributes.

E.g. So
<a href="index.php">Text Link</a>
would become
<a href="index.php?this=that">Text Link</a>

And the same with the <form action="index.php"> attribute.

Here's what I've got:

$CS_VARS = 'this=that&';
$CS_VARS = substr($CS_VARS, 0, strlen($CS_VARS)-1);
if (isset($CS_VARS) && !empty($CS_VARS)) {

$regexp = "<a\s[^>]*href=(\"??)([^\" >]*?)\\1[^>]*>(.*)<\/a>";
if(preg_match_all("/$regexp/siU", $Template, $regs, PREG_SET_ORDER)) {

	foreach($regs as $reg) {
		//href value
		$link = $reg[2];

		//If link contains a query 
		if (parse_url($link, PHP_URL_QUERY)) {  
			$mlink = $link.'&' . $CS_VARS; 
		} else { 
			$mlink = $link.'?' . $CS_VARS; 
		}

		//Repalce in html		
		$Template = str_replace($link, $mlink, $Template);
	}

}

$regexp2 = "<form\s[^>]*action=(\"??)([^\" >]*?)\\1[^>]*>(.*)<\/form>";
if(preg_match_all("/$regexp2/siU", $Template, $regs2, PREG_SET_ORDER)) {

	foreach($regs2 as $reg2) {
		//action value
		$link2 = $reg2[2];

		//If action contains a query 
		if (parse_url($link2, PHP_URL_QUERY)) {  
			$mlink2 = $link2.'&' . $CS_VARS; 
		} else { 
			$mlink2 = $link2.'?' . $CS_VARS; 
		}

		//Repalce in html		
		$Template = str_replace($link2, $mlink2, $Template);
	}

}
}

It seems to work, but when multiple forms are in the html, the $CS_VARS would repeat themselves so I actually end up with:

<form action="index.php?this=that&this=that&this=that... etc.

Also, for the text links it seems to sometimes remove the last character from the link before appending the $CS_VARS so I get:

<a href="index.php?id=123&this=that"> instead of
<a href="index.php?id=1234&this=that">

Any ideas as to what I'm doing wrong?

Cheers

nevvermind

Here's my humble code (yeah, I know; I'm using simple html dom parser. I'm an evangelist :mad: ):

<?php

include('simple_html_dom.php');
$html = new simple_html_dom();

$Template = <<<HTML
<a href="index.php">Text Link</a>
<form action="index.php"> </form>
<a href="index.php">Text Link</a>
<a href="another.php">Text Link</a>
HTML;

$html->load($Template);

foreach ($html->find('a[href^=index.php], form[action^=index.php]') as $element) {
    if (isset($element->href)) {
        $element->href .= '?this=that';
    } else {
        $element->action .= '?this=that&form';
    }
}
 // use same variable, or $output
$Template = $html->save();

echo $Template;

/*outputs this:

<a href="index.php?this=that">Text Link</a>
<form action="index.php?this=that&form"> </form>
<a href="index.php?this=that">Text Link</a>
<a href="another.php">Text Link</a>

*/

If you'll continue using regex to parse html, you'll have a whole lot of white nights. Sleep tight. :p

middleman666

Thanks nevvermind, looks like a nice bit of code.

Just one thing; I'm using regex as I don't actually know what the link value I want to change will be e.g. it won't always be index.php. Does the simple html dom parser have an option to deal with that?

I worked out why it appeared that some of my links got rid of the last character, it was the str_replace function replacing all links rather than the one I was working on. I put a loop in to make all links unique before trying to replace them with the new link which seemed to do the trick.

Cheers

nevvermind

Just one thing; I'm using regex as I don't actually know what the link value I want to change will be e.g. it won't always be index.php. Does the simple html dom parser have an option to deal with that?

I guess you could change to this, then:

foreach ($html->find('a[href], form[action]') as $element) {
    if (isset($element->href) && !empty($element->href)) {
        $element->href .= '?this=that';
    } elseif (isset($element->action) && !empty($element->action)){
        $element->action .= '?this=that&form';
    }
}

Anyways, you could check $element->href if it's empty, if it starts with some specific string etc.

You could optimize to this:

// search for this file
$php_file = 'index.php';

foreach ($html->find('a[href], form[action]') as $element) {
    if (strpos($php_file, $element->href) !== FALSE) {
        $element->href .= '?this=that';
    } elseif (strpos($php_file, $element->action) !== FALSE){
        $element->action .= '?this=that&form';
    }
}