Question

I am currently working on a replacement tool that will dynamically replace certain strings (including html) in a website using a smarty outputfilter.

For the replacement to take place, I am using PHP’s str_ireplace method, which reads the code that is supposed to be replaced and the replacement code from a database, and then pass the result to the smarty output (using an output filter), in a similar way as the below.

$tpl_source = str_ireplace($replacements['sourceHTML'], $replacements['replacementHTML'], $tpl_source);  

The problem is, that although it works great on my dev server, once uploaded to the live server replacements occasionally fail. The same replacements work just fine on my dev version though. After some examinations and googling there was not much I could find out regarding this issue. So my question is, what could influence str_replace‘s behavour?

Thanks

Edit with replacement example:

$htmlsource = file_get_contents('somefile.html');
$newstr = str_replace('<a href="http://www.somelink">Some text</a>', 'sometext', $htmlsource);  // the text to be replaced does exist in the html source

fails to replace. After some checking, it looks like the combination of “> creates a problem. But just the combination of it. If I try to change only (“) it works, if I try to change only (>) it works.

Answer 1

This was a trikcy problem, and it ended up having nothing to do with the str_replace method itself;

We are using smarty as a tamplating system. The str_replace method was used by a smarty ouput filter in order to change the html in some ocassions, just before it was delivered to the user.

Here is the Smarty outputfilter Code:

function smarty_outputfilter_replace($tpl_source, &$smarty)
{
    $replacements = Content::getReplacementsForPage();
    if (is_array($replacements))
    {
        foreach ($replacements as $replacementData)
        {
            $tpl_source = str_replace($replacementData['sourcecode'], $replacementData['replacementcode'], $tpl_source);
        }
    }
    return ($tpl_source);
}

So this code failed now and then for now apparent reason… until I realized that the HTML code in the smarty template was being manipulated by an Apache filter.

This resulted into the source code in the browser (which we were using as the code to be replaced by something else) not being identical to the template code (which smarty was trying to modify). Result? str_replace failed 🙂