How to RegExp this Base64 encoded 256-bit number without padding

Question

I'm trying to regex on the client as well as the server with this validation of a Base64 encoded 256-bit number without the = padding.

^[A-Za-z0-9+/]{42}[AEIMQUYcgkosw048]$

This is my code which isn't working as expected as any value seems to return true:

$.fn.validateKey = function() {
    var re = /^[A-Za-z0-9+/]{42}[AEIMQUYcgkosw048]$/
    var re = new RegExp($(this).val());
    return re;
};

How can I validate Base 64 encoded 256-bit signing keys without padding with javascript?

score 3 · Accepted Answer · edited May 23 '17 at 10:25

3

You're returning a RegExp object. You want to return its evaluation with an input string instead.

$.fn.validateKey = function() {
    var re = /^[A-Za-z0-9+/]{42}[AEIMQUYcgkosw048]$/;
    return re.test($(this).val());
};

Jan in the comments pointed out something interesting, in which the / doesn't need to be escaped in the regex (at least in my browser).

I believe it's due to being part of a character class.

edited May 23 '17 at 10:25

Community

answered Jan 18 '14 at 20:32

alex

Thank you so much alex! What do you mean by that last comment? I'm using this answer to validate a properly formatted Base64 encoding of a 256-bit number. http://stackoverflow.com/a/21151612/1382306 Is there some other pitfall that I'm missing? Thank you very much in advance! – Jan 18 '14 at 20:35
@Gracchus I jumped the gun. If it's a subset of encoded data (a number only), you should be right. It's also possible I'm on holidays and forgot a lot of programming. – alex Jan 18 '14 at 20:37
I hear you! Thanks again! – Jan 18 '14 at 20:45
does the slash inside the character group not need escaping? How so? – John Dvorak Jan 18 '14 at 20:46
Usually, the delimeter's parse the string which is sent to the regex engine. I would imagine it is seeing this `/^[A-Za-z0-9+/` as the regex, which should throw an error of unmatched `[`. But, this is JS so I am not sure. – Jan 18 '14 at 21:10

1 Answers1