Trapping user input error

dcjones

Hi,

I just can't get my head around the logic I need to perform this process.

I have a form where the user can select one of two items, simple.

item1 = a
item2 = b

When the form is submitted the POST vars "item1" and "item2" sent to another script.

I need to be able to trap an error if neither of the items is selected.

I.E: if item1 is selected, process, or if item2 is selected, proccess but if none were selected display an error.

The way I have been attacking it is:

if(empty($POST['item1) || (empty($POST['item2))){
$Error = "Error";
} else {
// do something
}

I know this logic is completely wrong. How best should this be done.

bpat1434

If you want to be overly specific about it, you can do what I normally do now which is check to make sure $_POST is defined, it has an array key of what you want and that array key's string length is greater than 0.

<?php

if (
    isset($_POST) &&
    (
        (array_key_exists('item1', $_POST) && mb_strlen(trim($_POST['item1'])) > 0) ||
        (array_key_exists('item2', $_POST) && mb_strlen(trim($_POST['item2'])) > 0)
    )
)
{
    // Process the form normally as at least one of them is populated
}
else
{
    // Error because either (a) the form was not posted, (b) the post data was empty or (c) neither item1 nor item2 were populated
}

Hope that helps.

dcjones

Hi,

Worked like a dream.

Many, many thanks.

bradgrafelman

bpat1434;11022745 wrote:
check to make sure $POST is defined

This is rather pointless (unless you want to bloat the code a bit) since $POST and all the other superglobals are always defined.

Also, unless the string '0' is a valid choice, what the OP had originally would work just fine... sans the parse errors.

bpat1434

Fair point. I do it there just because I'm so used to not operating directly on $_POST but other variables and it's always best to check to see if a variable is actually defined before trying to use it.

Weedpacket

bpat wrote:

array_key_exists('item1', $_POST)

The $_POST array isn't going to contain nulls (unless you're putting them in there yourself), only strings; [font=monospace]isset($_POST['item'])[/font] would be sufficient here.