php date validation

Question

Im trying to to set up a php date validation (MM/DD/YYYY) but I'm having issues. Here is a sample of what I got:

$date_regex = '%\A(0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[01])[- /.](19|20)\d\d\z%'; 

$test_date = '03/22/2010'; 
if (preg_match($date_regex, $test_date,$_POST['birthday']) ==true) {
    $errors[] = 'user name most have no spaces';`

Solution 1

You could use checkdate. For example, something like this:

$test_date = '03/22/2010';
$test_arr  = explode('/', $test_date);
if (checkdate($test_arr[0], $test_arr[1], $test_arr[2])) {
    // valid date ...
}

A more paranoid approach, that doesn't blindly believe the input:

$test_date = '03/22/2010';
$test_arr  = explode('/', $test_date);
if (count($test_arr) == 3) {
    if (checkdate($test_arr[0], $test_arr[1], $test_arr[2])) {
        // valid date ...
    } else {
        // problem with dates ...
    }
} else {
    // problem with input ...
}

Solution 2

You can use some methods of the DateTime class, which might be handy; namely, DateTime::createFromFormat() in conjunction with DateTime::getLastErrors().

$test_date = '03/22/2010';

$date = DateTime::createFromFormat('m/d/Y', $test_date);
$date_errors = DateTime::getLastErrors();
if ($date_errors['warning_count'] + $date_errors['error_count'] > 0) {
    $errors[] = 'Some useful error message goes here.';
}

This even allows us to see what actually caused the date parsing warnings/errors (look at the warnings and errors arrays in $date_errors).

Solution 3

Though checkdate is good, this seems much concise function to validate and also you can give formats. [Source]

function validateDate($date, $format = 'Y-m-d H:i:s') {
    $d = DateTime::createFromFormat($format, $date);
    return $d && $d->format($format) == $date;
}

^{function was copied from this answer or php.net}

The extra ->format() is needed for cases where the date is invalid but createFromFormat still manages to create a DateTime object. For example:

// Gives "2016-11-10 ..." because Thursday falls on Nov 10
DateTime::createFromFormat('D M j Y', 'Thu Nov 9 2016');

// false, Nov 9 is a Wednesday
validateDate('Thu Nov 9 2016', 'D M j Y');

Solution 4

Instead of the bulky DateTime object .. just use the core date() function

function isValidDate($date, $format= 'Y-m-d'){
    return $date == date($format, strtotime($date));
}

Solution 5

Use it:

function validate_Date($mydate,$format = 'DD-MM-YYYY') {

    if ($format == 'YYYY-MM-DD') list($year, $month, $day) = explode('-', $mydate);
    if ($format == 'YYYY/MM/DD') list($year, $month, $day) = explode('/', $mydate);
    if ($format == 'YYYY.MM.DD') list($year, $month, $day) = explode('.', $mydate);

    if ($format == 'DD-MM-YYYY') list($day, $month, $year) = explode('-', $mydate);
    if ($format == 'DD/MM/YYYY') list($day, $month, $year) = explode('/', $mydate);
    if ($format == 'DD.MM.YYYY') list($day, $month, $year) = explode('.', $mydate);

    if ($format == 'MM-DD-YYYY') list($month, $day, $year) = explode('-', $mydate);
    if ($format == 'MM/DD/YYYY') list($month, $day, $year) = explode('/', $mydate);
    if ($format == 'MM.DD.YYYY') list($month, $day, $year) = explode('.', $mydate);       

    if (is_numeric($year) && is_numeric($month) && is_numeric($day))
        return checkdate($month,$day,$year);
    return false;           
}         

View more solutions

Comments

[Cody Caughlan]

This is the best solution as it also checks for invalid dates, e.g. Feb 29. A pure regex approach based on formatting would allow invalid dates.

[Madara's Ghost]

+1 for a regexless solution. Not all problems need a regex solution.

[zerkms]

regex solution also checked for a format, while this doesn't. If string foobar is passed - you'll get notices

[salathe]

Let's come into the 21st century. DateTime::createFromFormat() and DateTime::getLastErrors(). Thank me later.

[Sk446]

@salathe has the best approach. Nicolás should really update his answer as it's providing an old approach of doing this.

[s3m3n]

It's worth to mention that you can check it straight with DateTime::createFromFormat() only, by checking if it's false, so if(DateTime::createFromFormat('m/d/Y', $test_date) === false) exit('bad date format');

[salathe]

Only very crudely @s3m3n. For example, without checking for warnings, "44/33/2211" is a valid m/d/Y date (it is 2nd Sep 2214 btw).

[s3m3n]

You are right, but in my case I'm only validating if moderator didn't make literal mistake in date format which is going directly to database instead of logical sense of given date. Someone else might need the same thing.

[Nitsan Baleli]

DateTime::createFromFormat(PHP 5 >= 5.3.0)

[o0'.]

This is not always the best approach. If you receive the input already in separated values, but you don't know how exactly they are formatted (M vs. MM, YYYY vs. YY), I think checkdate would be more flexible and accept anything that resembles a valid date. Additionaly, with DateTime, if I write 31 as the month it will be considered valid, and simply add 2 years and set it to July (since 31%12 = 7). I really don't think this would be expected behaviour by many people…

[Gras Double]

Why/when is the extra verification $d->format($format) == $date needed?

[BillyTom]

But why would you want regex in the first place?

[jjwdesign]

@Gras Double - Validation. He's returning true/false, but ensuring that the DateTime object was created and that the formatted DateTime equals the function input $date.

[Gras Double]

Sure, but a return (bool) $d; would do it. My question was, as the createFromFormat succeeded, in what scenario could the $d->format() be different from the input?

[Gras Double]

I have found this: validateDate('Mon, 21-Jan-2041 15:24:52 GMT', DateTime::COOKIE);. Returns false because the ->format() produces "Monday" instead of "Mon". Though, it would be better to return true, as the input is valid. I'm updating the answer.

[Gras Double]

Found out a purpose for the ->format() verification. Answer updated again.

[Gras Double]

@ksimka Actually yes, see answer above.

[Rich R]

The call to format will throw an exception if the date is invalid.

[GordonM]

This question has already had plenty of far superior answers, what's more it's years old. Your answer adds nothing. Please don't indulge in necromancing.

[rolinger]

Everyone, in multiple posts, keeps saying to use checkdate. But checkdate fails if the year is : 2, 20, 202, 2020 or even 20201 - it returns true every time.

[Andrew Rump]

Why not just test if strtotime() === false?

[Nicolás Ozimica]

@rolinger Why should checkdate fail with such years??? First: are they invalid years? Second: the documentation for checkdate explicitly states that: "The year is between 1 and 32767 inclusive."