Form action validation

[meltingpoint]

Form has combo box that lets users pick - Delete or Edit with corresponding values of delete and edit sent via $_POST.

 

I want to validate that either one or the other has been picked.  Doing this will keep from someone trying to inject some other crud.  So I tried ;

 

<?php
if($action !== 'delete' || 'edit'){ echo "ERROR- you must choose an appropriate form Action.  Please try again.";}
?>

It does not seem to work.  Before I go on, is my syntax / coding correct?

 

If I do it like below- it works.

<?php
if($action !== 'delete' or $action !== 'edit'){ echo "ERROR- you must choose an appropriate form Action.  Please try again.";}
?>

Just trying to figure out the proper coding method.

 

Tks

[Psycho]

Hmm, the first one doesn't work and the second one does. I wonder which one is correct?

 

When using and AND or OR, the parts on each side of that clause are interpreted individually. So, in this case:

if($action !== 'delete' || 'edit')

 

It is saying if [$action !== 'delete' ] is true OR if ['edit'] is true. It doesn't know you wanted to compare 'edit' to $action. Each clause of the condition stands on it's own. In this case (with only two options), a more simple approach would be to simply check for one value and if not that value then choose the other. I would default to the edit.

$action = (isset($_POST['action']) && $_POST['action']=='delete') ? 'delete' : 'edit';

 

Or, to make your code easier to read you could use in_array() which is also useful wehn you have more than two values

if(!in_array($action, array('edit', 'delete')))
{
    echo "ERROR- you must choose an appropriate form Action.  Please try again."
}

[meltingpoint]

Hey- nice idea with the array.  So......should work...

<?php
$action = $_POST['action'];

if(!in_array($action, array('edit', 'delete')))
{
echo "ERROR- you must choose an appropriate form Action.  Please try again";
}
?>

 

I did not know that you could use in_array() in that way. 

Excellent!  I will try it and see if it works.

 

Thanks