Issue #1

Email header names have a set value, but in practice SMTP servers do what they want.  So this is the required header name for content type:

Content-Type: <some value>

But variations exist, such as this:

Content-type:  <some value>

Rather than trying to guess every possible combination, I think it would be good to simply ignore the case of the header name.

(I have modeled header names as initiators.)

Issue #2

The spec says that the value of the content type is case insensitive, so all the following possibilities (and more) are allowed:

Content-Type:  text/html

Content-Type:  TEXT/HTML

Content-Type:  Text/Html

Content-Type:  tExT/hTmL

So obviously I need to be able to ignore the case of the header’s value.

(I have modeled the type (e.g., text) and the subtype (e.g., html) as elements.  And as there’s obviously a limited set of allowed for each, I’ve constrained these with an enumerated list.)

I have attached a simplified version of the schema I’m using for the content header.  How would I modify it in order to ignore the case of the header name and the header value?

TIA!