PHP: Validation for required field - php

Question

I want to validate a field which is required. I am using following condition to check whether the field is not empty:
isset($value) && !empty($value)
But if I write 0 in the fields, it will still say the field is required. The empty() function considers 0 as an empty value as told in PHP manual but what else should I do? I have tried writing many conditions but they didn't work as expected.
I saw user contributions and found:
empty($var) && !is_bool($var)
I tried adding it to my condition like this but didn't work:
isset($value) && !empty($value) && is_bool($value)

Answer 1

Try below code:
$value = 0;
if(isset($value) && $value !== "")
{
echo "Field not required";
}
else
{
echo "Field required";
}
Output:
Field not required
Demo:
http://3v4l.org/JWJbj
Explanation:
The integer 0 is truthy. It means that anything that checks it in a boolean'ish manner will treat it as false. In particular, !empty($value) will evaluate to false, so is_numeric would never even get a chance to fail.
Short version: empty is too wishy-washy in this case. Check for null and '' explicitly (with data-type hence used !==).

Answer 2

You can't check for empty. Basically you can only stick to the isset test.
If a field in the form was not filled this variable field will not be inside the $_POST superglobal and isset will return false. If the user typed 0 the variable name will exist inside $_POST isset will return true.

Answer 3

I would do it as following:
function emptyTextValue($value)
{
return trim((string) $value) !== '';
}

Answer 4

You know that all you get is a string, so you don't need full functionality of empty() function:
isset($_POST['yourFieldName']) && $_POST['yourFieldName'] !== ''

Answer 5

You can replace the empty function by :
$value !== ""
If it's not exactly empty, then it will validate the condition.

Answer 6

What I've done for my test is convert the empty check to a strlen check. Because PHP is so friendly, you can run a string comparison on the value. A value of null will return a 0 length string, while a value of 0 will return a length of 1. So what I've done is this:
if(isset($val) && strlen($val) > 0){
// Do stuff
}

Answer 7

Try
isset($value) && $value != ''

Answer 8

I have found a nice condition by myself.
$value === 0 || $value === "0" ? isset($value) : isset($value) && !empty($value)
This works perfectly for every case.

Answer 9

I would check to be sure that the form had been submitted and then trim the field 'msg' in case there were any white space chars, i.e. newlines, carriage returns, tabs, spaces and then test that result to make sure it's not the empty string as follows:
<?php
if ( isset($_POST['msg']) && trim($_POST['msg']) !== '') {
// other code
}