Underscores in Root URL not supported

AutoImport-Schulteatq

Specs

DAVDroid Version 0.5.14-alpha from F-Droid
ownCloud 6 hosted on virtual server
LG Nexus 4, Android 4.4.4

Summary

Apparently the Root URL does not support underscores in the domain when creating a new account. The next button does not work (simply does not respond) after entering the server details. Root URLs without underscores work.

Steps to reproduce:

Settings -> Accounts -> Create new account
Set Root URL to a domain with underscores (e.g. ud12_34.ud12.udmedia.de/...)
Set random user name and password
Try click on the next button -> nothing happens, it does not even try to connect

If I remove the underscore (e.g. ud1234.ud12.udmedia.de/...) DAVDroid tries to connect, however it fails due to the server address being invalid (as expected). If I use my alternate server URL cloud.domain.net/..., everything works fine including login. However, I don't have a SSL certificate issued for that domain, hence I can't use HTTPS then.

rfc2822

Host names MUST – in contrast to DNS names which are not A or MX records – not contain underscores:

http://domainkeys.sourceforge.net/underscore.html
RFC 1738 3.1, look for "host"
RFC 1034 3.5

The host name validation is not done by DAVdroid but by Java: DAVdroid will allow any host that is correctly parsed by URI and doesn't raise URISyntaxException.

Closing because working as intended.

(You may use a hyphen instead).

AutoImport-Schulteatq

Interesting - I should talk to my provider then.
Thanks for the info.

AutoImport-thican

Hello rfc2822,

I come back on this "issue", because I met it.
As you said, and indeed you are right, underscore should not be allowed in DNS records.

But still, your application has a problem: a lack of warning/error message when this error happens.

Because of this behaviour (no warning at all), your application just looks like it is "no responding", and users -- which are not aware of this information, like I did -- will just quit your application and delete it when they meet this bad behaviour … like I did.

Therefore, I think you should handling the URISyntaxException and warn the user (simple message like "Warning/error: underscores are not allowed in hostname.")

Thanks for support.

--
Thibaud CANALE

PS: respecting standards is good, handling exceptions is better.