Best practice for handling vertical tabs and other invalid xml characters

Question

I have an application which (like many others) takes in user input, stores it in a database and then later processes it using (amongst other things) XML tools. The application t

Answer 1

Yes, unfortunately some characters are illegal in XML, and have no entity equivalent. As one of those examples, see:

http://www.jdom.org/docs/apidocs.1.1/org/jdom/Element.html#setText(java.lang.String)

which is a String setter... that can throw an exception! Vertical tab is exactly one of those characters for which there is no XML entity, nor a way to "escape" it with XML alone.

I'm working around this myself by using base64 encoding to sanitize strings that might harbor those characters. It's a bit silly, since I have to base64-encode and decode all the time, but I don't think there's a good alternative.

Answer 2

You should escape them using amperstand (� through &#0x1F), then decode/restore them at the end.

See XmlTextWriter incorrectly writing control characters