PHP check if string is properly formatted

Question

I have a PHP application which should require a special activation key for unlocking. So I want to create scripts which will check if $user_input is properly formatted.

An activation key will be like this:
1E63-DE12-22F3-1FEB-8E1D-D31F

Numbers and letters spacing may vary.
So activation key may be also like this or different:
1EE3-1E1C-R21D-1FD7-111D-D3Q5

Colons are separated with -
Every colon contains 4 characters which are a mix of letters and numbers

Thanks in advance for any help :)

I would use regex for this, check this question: stackoverflow.com/questions/2428343/regex-for-product-key — younes0
– younes0, Commented Nov 3, 2013 at 20:00
Why do you need to check if the code if well formatted, since if they mismatch something, the format or the code, it won't work. However, I would suggest, if you want the user to type in this format, put 6 text boxes with 4 maxlength, then concatenate with - each when you recieve the input — Ivan Yonkov
– Ivan Yonkov, Commented Nov 3, 2013 at 20:05
This is just for format checking, after that input will go to further checking. Anyway, your suggestion/idea is very good so I may use it. Thank you. — xZero
– xZero, Commented Nov 3, 2013 at 20:34

user2518044 · Accepted Answer · 2013-11-03 20:10:39Z

17

You have to use a regular expression for that. I've tested this regex here: http://www.phpliveregex.com/

<?php

$key   = '1E63-DE12-22F3-1FEB-8E1D-D31F';
$regex = '^[A-Z0-9]{4}-[A-Z0-9]{4}-[A-Z0-9]{4}-[A-Z0-9]{4}-[A-Z0-9]{4}-[A-Z0-9]{4}$';

if (preg_match($regex, $key)) {
    echo 'Passed';
} else {
    echo 'Wrong key';
}

answered Nov 3, 2013 at 20:10

user2518044

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1 Comment

xZero Over a year ago

This works well after modification. Without modification it throws error "Warning: preg_match(): No ending delimiter '^' found" so I modified it to this $regex = '/^[A-Z0-9]{4}-[A-Z0-9]{4}-[A-Z0-9]{4}-[A-Z0-9]{4}-[A-Z0-9]{4}-[A-Z0-9]{4}$/'; Thanks, your script does exactly what I wanted it to do.

SyntaxSwearer · Accepted Answer · 2013-11-03 20:15:05Z

2

This regex will match keys like the one you posted, and will also work if lowercase letters are included:

^([A-z0-9]){4}-([A-z0-9]){4}-([A-z0-9]){4}-([A-z0-9]){4}-([A-z0-9]){4}-([A-z0-9]){4}$

If you want only uppercase letters, change all the "z" in that regex for "Z"

answered Nov 3, 2013 at 20:15

SyntaxSwearer

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