Eval() problem in PHP

Question

Quite some time ago I wrote a RSS parser. It worked fine until now, when I turned my error and notice reporting on. Currently I keep getting quite a lot of notices that tell me that something is wrong in the function. I tried solving this problem on my own, but I had no success. Could You please help me with this error?

The error:

Notice: Undefined index: RSS in C:\xampp\htdocs\Dropbox\RECtus\System\sysFiles\libarys\myRSSParser.lib(103) : eval()'d code on line 1

Notice: Undefined index: LINK in C:\xampp\htdocs\Dropbox\RECtus\System\sysFiles\libarys\myRSSParser.lib(103) : eval()'d code on line 1

The script:

function parseData($parser, $data) {
        if(!trim($data)) return;
        $RSS = '';
        $evalcode = "\$this->output";

        foreach($this->tags as $tag) {
            if(is_array($tag)) {
                list($tagname, $indexes) = each($tag);

                $evalcode .= "[\"$tagname\"]";
                if(!isset(${$tagname})) ${$tagname} = '';
                if(${$tagname}) $evalcode .= "[" . (${$tagname} - 1) . "]";
                if($indexes) extract($indexes); 
            } else {
                if(preg_match("/^([A-Z]+):([A-Z]+)$/", $tag, $matches)) {
                    $evalcode .= "[\"$matches[1]\"][\"$matches[2]\"]";
                } else {
                    $evalcode .= "[\"$tag\"]";
                }
            }
        }
        eval("$evalcode = $evalcode . '" . addslashes($data) . "';");
}

Line 103 is the eval() line.

Please provide a dump of $evalcode just before the eval(). Also, one of the two $evalcode strings in the eval() call should probably be escaped, e.g. eval("\$evalcode = $evalcode . '" ... — jensgram
– jensgram, Commented Apr 1, 2011 at 10:52
I would say the real problem is that you're using eval() in the first place. There are several XML parsers and a few RSS-specific XML parsers available for PHP ... The best way to really solve your problem is not using eval(), it's notoriously hard to debug and prone to errors. — Martin Tournoij
– Martin Tournoij, Commented Apr 1, 2011 at 10:53
have you tried echo on eval argument to see what eval() tries to evaluate? — Wh1T3h4Ck5
– Wh1T3h4Ck5, Commented Apr 1, 2011 at 10:53
[putting flame retardant suit on] code is crap. Abandon you "solution" entirely, and write a new one, you are looking for error in fatal error. — Dejan Marjanović
– Dejan Marjanović, Commented Apr 1, 2011 at 10:55

Community · Accepted Answer · 2023-11-17 19:42:58Z

2

Why are you using eval() ?

It seems you're just trying to concatenate portions of string, no ?

If so, why not just... concatenate portions of strings ?

Basically, you should be able to do something like this :

$this->output = array();
$this->output['...'] = 'some string';
$this->output['...'] = array();
$this->output['...']['...'] = 'some other string';

edited Nov 17, 2023 at 19:42

CommunityBot

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answered Apr 1, 2011 at 10:54

Pascal MARTIN

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2 Comments

Gumbo Over a year ago

This is not what his code is doing. It’s rather something like $this->output[…] = $this->output[…].$data.

Pascal MARTIN Over a year ago

@Gumbo : ergh, you're right! Thanks for your comment, I've edited my answer a bit :-)

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