Re: Status and X-UIDL headers

[Brian Stafford <brian stafford uklinux net>]

On Mon 01:55, 17 June 2002 Julian M Catchen wrote:
> Hey Everyone,
> 
> I was hoping that someone on this list could tell me where the "Status" and 
> "X-UIDL" headers are defined in the standards documents?

They aren't.  Normally headers like these are added by a MUA to maintain state 
associated with received messages.

>  Are these defined or mentioned in an RFC somewhere, or do most POP servers 
> just use them?

Almost no and no.  RFC 2076 is an informational RFC which reviews headers 
commonly found in messages and has some background information on the use of 
Status:.  Nevertheless, this does not make it standard in any way and remember 
that 2076 is *not* a standard.

>  I realize the "X" in "X-UIDL" means it is *not* standard, but it seems to 
> be used in too many places to be that unstandardized.

The IESG would *never* allow a X- header to be standardised in an RFC.

>  Also,  I was wondering if anyone can tell me to what extent Balsa makes use 
> of them.  Does Balsa use these to determine if a message has been read?
> 
> I am looking to use these headers in a mail project I am working on, but 
> don't want to unless they are pretty reliable across implementations.

You've just answered your own question, they aren't standard and you cannot 
make assumptions about their availability, syntax or semantics.

When designing systems taht must interoperate on the internet there is *only 
one* way to go about it.  Get the relevant standards and implement only what 
they permit.  Later on you can "extend" to accomodate known buggy programs 
with which your program must interoperate.  However this should not break the 
standard as this will affect programs written by conscientious authors who 
adhere to standards (yes, there are some).  Never ever base a design on the 
empirical review of currently deployed software, that way you only propagate 
the bugs and design errors in such programs.  That compromises 
interoperability for everybody and makes the world a worse place leading to 
hunger, poverty, Britian not adopting the Euro, global warming, etc.

Brian Stafford