'Errors' array stays empty

[Opimus]

Simple (not working) snippet that validates input.

//If something wrong, populate $errors
		$required_fields = array('menu_name', 'position', 'visible');
		foreach($required_fields as $fieldname) {
			if (!isset($_POST[$fieldname]) || (empty($_POST[$fieldname]) && $_POST[$fieldname] != 0)) {
				$errors[] = $fieldname;
			}
		}
//If something wrong, populate $errors
$fields_with_lengths = array('menu_name' => 30);
		foreach($fields_with_lengths as $fieldname => $maxlength) {
			if (strlen(trim(mysql_prep($_POST[$fieldname]))) > $maxlength) {errors[] = $fieldname;}
		}

Then I do update if $errors array is empty.

if (empty($errors)) {
	//Perform update
} else {
       //Errors occurred: Display $message
}

The problem is that only the second validator fills $errors array (i.e. if input exceeds 30 characters) but first one doesn't if I input empty string.

[halojoy]

if(!isset($_POST[$fieldname]) || (empty($_POST[$fieldname]) && $_POST[$fieldname] != 0))
{
    $errors[] = $fieldname;
}

If I am not wrong,
I think you should take a Closer Look
at that IF statement.

regars 🙂
halojoy

[Opimus]

Have reexamined the manual:

The following things are considered to be empty:
"" (an empty string)
0 (0 as an integer)
"0" (0 as a string)
NULL
FALSE
array() (an empty array)
* var $var; (a variable declared, but without a value in a class)

isset will return empty string as 'true' (with exclamation mark 'false'), but shouldn't empty return 'true' on empty string?

The last part of if statement (!= 0) is only for passing in 'visible' as $fieldname which can be either true/false (1/0).

What is it that I don't see in this if statement? :o

EDIT: I suspect it is that added condition && $_POST[$fieldname] != 0 that "lets through" empty input? That means that empty string equals to 0?!

[laserlight]

I suspect it is that added condition && $_POST[$fieldname] != 0 that "lets through" empty input? That means that empty string equals to 0?!

Yes, an empty string is equal to 0. However, an empty string is not equal to '0'.

[NogDog]

If the number zero can be a valid entry in a field, I prefer to do...

if(!isset($_POST['field']) or trim($_POST['field']) [color=red]===[/color] '')
{
   // error
}

...using the "identical" operator "===".

[Opimus]

So easy yet so hard for me.

Thanks A LOT!

Have you considered implementing gratefulness meter in the forums?

[laserlight]

...using the "identical" operator "===".

I do not think that is necessary, actually. trim() returns a string, so trim($x) === '' <=> trim($x) == ''.

Have you considered implementing gratefulness meter in the forums?

See Reputation? 🙂

[Opimus]

Sure thing, identical operator does its job regarding the empty-string-input (indeed, empty string is treated as 0).

But... now the value that's sent from radio-button (from form) is being rejected when 'visible' is set to 0 (zero):glare:

I don't get it:
first) empty && different from 0 -> 'visible' as 0 gets through
now) empty && not identical to 0 -> 'visible' can't get through anymore, it is put into $errors array

EDIT: Here's what I've found out:
'not identical' operates like this: if $a is not equal to $b, or they are not of the same type

And I've also found out that option selected from radio-button is sent as a string.

So now, what's the most compatible and efficient solution? My neophyte (:o) intuiton comes up with only one, that is to cast 'visible' into integer.

Please, don't take my scrawlings as granted (not that you do😃), rather someone confirm my assumptions (on how 'not identical' *should work and that radio-button option is really sent as string).

I doubt my doubts.

[laserlight]

What exactly are you trying to do?

NogDog's solution should work; I just pointed out that === is not necessary and == will do. In the first place, incoming variables are always either strings or arrays, or they do not exist.

My point is that 0 is an integer literal and '0' is a string literal. '' == 0 is true, but '' == '0' is false. As such, another solution is to use $POST['name'] == '0', or $POST['visible'] != '0'. Do not mess around with "identical" as it does not apply here.

[Opimus]

That got it working.
Before: (empty($fieldname) && $fieldname != 0)
After: (empty($fieldname) && $fieldname != '0')

laserlight wrote:

0 is an integer literal and '0' is a string literal ('' == 0 is true, but '' == '0' is false)

I understand this (think so) but to clear it out for me:

Visible is sent as a string "0", right? Does "0" != 0 (without quotes!) evaluate to false and "0" equals 0, right?

Menu Name when empty is sent as empty-string " ". How is it possible that somebody else could "pull it off" with before-validator and inputing empty-string would give him error ("" not equal to 0 for him)?

[laserlight]

Does "0" != 0 (without quotes!) evaluate to false and "0" equals 0, right?

Yes.

Menu Name when empty is sent as empty-string " ". How is it possible that somebody else could "pull it off" with before-validator and inputing empty-string would give him error ("" not equal to 0 for him)?

Sorry, I do not understand your question.

[Opimus]

Somebody else entered empty string with before-validator (with !=0) and it returned him an error (as it was meant) but it didn't on my machine.

Thank you for your help.