PHP validate date - php

Question

im trying to validate a date in the YYYY-MM-DD in the $immerseusnorm i have tried the code below but its returning No!
<?php
$json = file_get_contents("http://www.wowtrack.org/plugins/guild/EU/Emerald%20Dream/VII?format=json", true);
$decode = json_decode($json, true);
$realmrank = " ". $decode[realmRank] ."";
$immerseusnorm = " ". $decode[encounters][0][completedOn]."";
if (preg_match("/^[0-9]{4}-(0[1-9]|1[0-2])-(0[1-9]|[1-2][0-9]|3[0-1])$/",$immerseusnorm))
{
$immerseusnorm = "Yes";
}
$immerseusnorm = "No";
echo "Realm Rank: $realmrank<br \>";
echo "Immerseus Normal - Completed On: $immerseusnorm<br \>"
Any help would be great
Thanks

Answer 1

I would attempt to create a DateTime object based on the format. That way, you can validate both the format AND that the date it suggests is valid. For example, a simple regex match with your pattern would allow something like 2014-02-31, which obviously is not a valid date.
The only challenge with DateTime is that a date like 2014-02-31 gets "fixed" to 2014-03-03, instead of returning false from DateTime::createFromFormat(). So you can just check back against the input string to make sure the date didn't get changed.
Putting it into a function could look like this:
function validate_date($input_date, $format = 'Y-m-d') {
$datetime = DateTime::createFromFormat($format, $input_date);
if(false === $datetime) {
return false;
} else if ($datetime->format($format) === $input_date) {
return true;
} else {
return false;
}
}
// usage
if (validate_date($immerseusnorm)) {
// validation passed
} else {
// validation failed
}

Answer 2

I guess you should add else around the second $immerseusnorm, it now always sets it to no. So better change this:
if (preg_match("/^[0-9]{4}-(0[1-9]|1[0-2])-(0[1-9]|[1-2][0-9]|3[0-1])$/",$immerseusnorm))
{
$immerseusnorm = "Yes";
}
$immerseusnorm = "No";
to:
if (preg_match("/^[0-9]{4}-(0[1-9]|1[0-2])-(0[1-9]|[1-2][0-9]|3[0-1])$/",$immerseusnorm))
{
$immerseusnorm = "Yes";
}else{
$immerseusnorm = "No";
}

Answer 3

It seems that your regex is working.
you have missed a point here.
this line is always executed :
$immerseusnorm = "No";
You should have else of your if condition.
try this:
if (preg_match("/^[0-9]{4}-(0[1-9]|1[0-2])-(0[1-9]|[1-2][0-9]|3[0-1])$/",$immerseusnorm))
{
$immerseusnorm = "Yes";
}
else{
$immerseusnorm = "No";
}
Sample demo : see demo : https://eval.in/107333