Alphanumeric validator and UTF8 supported characters in usernames

[ajnyga]

Hi,

The Finnish language includes letters like ä, ö and å. For Finnish users these are part of the definition of "alphanumeric".

However, the validator here does not seem to take into account these letters: https://github.com/pkp/pkp-lib/blob/master/classes/form/validation/FormValidatorUsername.inc.php#L31

Also I think the registration form should have a description under the username field that would show the requirements for the username. This also applies to the password field.

(or just remove usernames altogether and just use email as a username. I mean what is it good for anyway?)

[asmecher]

@ajnyga, I think this is essentially a dupe of #906. Essentially the conventions have evolved far enough away from [a-zA-Z]+ that I'm open to both proposals -- relaxing the allowed characters, and moving to email-based logins.

[ajnyga]

There are many sides to this.

Login by email is good, but I did realize that the username is a handy shortname to have around the workflow.

I do think the current username rules are too strict, but we should not allow whole names as usernames either. It beats the purpose imho.