Why won't my PHP form validation work?

Question

When I try to submit a form on my site I get the following error:

Fatal error: Cannot access empty property in functions/form_validation.php on line 15

The code for form validation is:

class Validation {
    var $success;
    var $post_data;
    var $errors;
    var $delimiter;


    function Validation($HTTP_POST_DATA) {
        $this->success = true;
        $this->errors = false;
        $this->$post_data = $HTTP_POST_DATA;
        $this->delimiter = "|";
        while(list ($key, $val) = each ($this->$post_data)) {
            $this->{$key} = $val;
        }
        reset($this->$post_data);
        while(list ($key, $val) = each ($this->$post_data)) {
            if(method_exists($this, $key)) {
                $cmd = "\$this->".$key."();";
                eval($cmd);
            }
        }
    }

The code from the form page is:

 include_once($APP_ROOT . "functions/index.php");
    include_once($APP_ROOT . "functions/form_validation.php");
    $CONTINUE = TRUE;
    $valid = new Validation($_POST);
    if($CONTINUE = $valid->success) {

This code used to work just fine before we upgraded to PHP5. Any idea what I need to change to get it working again?

Thanks

Since your lines are not numbered here, and we don't know if there's more code around that, can you point out which of those lines is throwing the error? — Geeky Guy, Sep 18 '13 at 19:07
Are you using PHP 4?. If not then, read the documentation http://php.net/manual/en/language.oop5.php You don't have to use `var` anymore. You all can use `public function __construct() {}` as your constructor. — Ryan, Sep 18 '13 at 19:09
Also, as a side note, there is no need to use eval. Instead of: `$cmd = "\$this->".$key."();"; eval($cmd);` Simply do: `$this->$key()` — Mark, Sep 18 '13 at 19:40

score 7 · Answer 1 · answered Sep 18 '13 at 19:08

7

$this->$post_data should be $this->post_data

In future, try looking at the line that the error message points you do, because usually that's where the problem is! ;)

answered Sep 18 '13 at 19:08

Niet the Dark Absol

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Thanks. Changing every instance of $this->$post_data should be $this->post_data worked. Can you explain to me in simple terms why I needed to make that change after going from PHP4 to PHP5? – user2791808 Sep 18 '13 at 19:15
Um... I'm not sure why I should have to, since you have plenty of other property accesses right there, but for some reason you put an extra `$` in that specific one... – Niet the Dark Absol Sep 18 '13 at 20:20

score 6 · Accepted Answer · answered Sep 18 '13 at 19:08

6

Change this:

$this->$post_data = $HTTP_POST_DATA;

To this:

$this->post_data = $HTTP_POST_DATA;

answered Sep 18 '13 at 19:08

Mark

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Thanks. Changing every instance of $this->$post_data should be $this->post_data worked. Can you explain to me in simple terms why I needed to make that change after going from PHP4 to PHP5? – user2791808 Sep 18 '13 at 19:20
1

To be perfectly honest, I have no idea, though I have absolutely no experience with PHP4. I would however, love to hear why this ever worked. – Mark Sep 18 '13 at 19:36

score 1 · Answer 3 · answered Sep 18 '13 at 19:11

You can take care of the immediate problem by modifying the line to read:

if(property_exists(this, $key)) $this->{$key} = $val;

If you'd like to know exactly WHY this isn't working try printing the POST array in debug mode:

function Validation($HTTP_POST_DATA) {
  echo '<pre>'. print_r($HTTP_POST_DATA, true). "</pre>\n";
... rest of method ...

Also, change all instances of $this->$post_data to $this->post_data

Why won't my PHP form validation work?

3 Answers3