Some Regexp questions

Hello,

I have a registering form with the input fields for realname (two
seperate fields for surname and forename), username, password,
password again and email.

I want to check each each input field and redirect to another page
when all the fields are valid. If not, the form should show up again,
with all the invalid input fields highlighted and with the adequate
error messages displayed.

Therefor, I write a function for every input field, that checks the
validity of it.
I thought I'd do that with regexp/preg_match, but I'm a big newbee...

I already found a quite good solution for the email field (http://
www.ilovejackdaniels.com/php/email-address-validation), what do you
think about it?

So, what I still need, are the validation functions (regexps) for the
surname, forename, username, password an the second password.

The realname (surname/forename) should only contain all letters (also
special characters like an umlaut, =B4, ` and all that kind of stuff), a
"-" and a space.

The username should only consist of letters (no special characters),
numbers, "_" and "-" (or do you guys suggest any other allowed
characters?).

For the password, I guess I should allow every possible combination
and check for a minimum lenght...


I hope you guys can help me with those regexps or whatever solution
you suggest for my "problem".


Thanks!

Re: Some Regexp questions

On Fri, 01 Feb 2008 18:36:54 +0100, k3pp0 wrote:

> Hello,
>
> I have a registering form with the input fields for realname (two
> seperate fields for surname and forename), username, password,
> password again and email.
>
> I want to check each each input field and redirect to another page
> when all the fields are valid. If not, the form should show up again,
> with all the invalid input fields highlighted and with the adequate
> error messages displayed.
>
> Therefor, I write a function for every input field, that checks the
> validity of it.
> I thought I'd do that with regexp/preg_match, but I'm a big newbee...
>
> I already found a quite good solution for the email field (http://
> www.ilovejackdaniels.com/php/email-address-validation), what do you
> think about it?

Better then most, not entirely correct yet. See if you can Friedl's regex
for email validation, it's a few pages long. However, being more
'allowable' for email addresses usually does the trick. Just make sure no
header injection is done & there's only 1 @ present.

> So, what I still need, are the validation functions (regexps) for the
> surname, forename, username, password an the second password.
>
> The realname (surname/forename) should only contain all letters (also
> special characters like an umlaut, ´, ` and all that kind of stuff), a
> "-" and a space.

'That kind of stuff' doesn't cut it in regexes. What kind of stuff?
With a proper locale you can use \w for the letter, else use utf-8 mode
and something like \p{L}. You do have to define what 'other' stuff is and
put that into a character class. Personnaly, I usually trust people who
have entered their name to be correct, and I'd just use /\S+/ (meaning: at
least one character that is not whitespace). /\w+/ is also an option.

> The username should only consist of letters (no special characters),
> numbers, "_" and "-" (or do you guys suggest any other allowed
> characters?).

I'd suggest _all_, I don't care it someone chooses a weird username,
allthough I'd probably limit it to a certain length.
Your suggestion would be: /^[a-z0-9_-]+$/i, mine would be /^.{1,16}$/s
(limited from 1 to 16 chars here).

> For the password, I guess I should allow every possible combination
> and check for a minimum lenght...

Yup, /^.{8,*}$/s, and only store some hash of the (md5()/sha1() etc.).

On a side note: I'd use trim() on all strings before matching.
--
Rik Wasmus