Re: LINK TYPE=override/type

Ian Graham (igraham@smaug.java.utoronto.ca)
Thu, 22 Jan 1998 18:30:09 -0500 (EST)


From: igraham@smaug.java.utoronto.ca (Ian Graham)
Message-Id: <199801222330.SAA13988@smaug.java.utoronto.ca>
To: neil@bigpic.com
Date: Thu, 22 Jan 1998 18:30:09 -0500 (EST)
Cc: www-html@w3.org
In-Reply-To: <199801222245.PAA00544@underworld.bigpic.com> from "Neil St.Laurent" at Jan 22, 98 03:53:22 pm
Subject: Re: LINK TYPE=override/type

Neil said:
> 
> > that an author may want to process or view the resource by some
> > mechanism other than the browser's default handling for the given
> > type, is no argument for using TYPE to arbitrarily override the 
> > server's information..
> 
> That is nice for HTTP, but HTML has no necessity to be delivered over 
> HTTP, other protocols don't provide content type, and if TYPE is 
> there it would be nice to have a consistant model.

I agree with consistency -- but believe that the software that 
assembles the message must be given higher priority, since it in principle
has the 'latest' information available about the resource and its type. 
Certainly both MIME-HTML (smtp/nntp) and HTTP -- which are (or will be) 
the dominant protocols for delivering content, provide explicit MIME types. 
There are no upcoming protocols I know of that do not include an explicit 
typing mechanism, either as a header, or a manifest of some sort.

> 
> > Indeed, one can just as easily argue for HTTP overriding TYPE -- 
> > suppose I update a single stylesheet so that it now corresponds to 
> 
> I would say that since document standards are going to change more 
> rapidly than architecture standards it makes sense to provide the 
> document with the override capability.

This assumes that you can self-consistently manage all linked documents,
which is not the case.  For example, someone linking to your document might 
specify the type of your document using TYPE. But, if you subseqently 
change the type, their documents will break.   

This only argues for ensuring that the s/w assembling the message 
specifies the correct type, since only in that way can you ensure that
all documents -- both the ones you manage and the ones you don't -- 
know the correct type.

At the same time, I believe TYPE should play a role in error handling 
-- for example, if the HTTP-specified type seems to be in error, then 
the browser could fall back to the TYPE-specified value, and see if that
works. And if that doesn't work, the browser could try heuristics on the
file, to try and determine the correct type (i.e. ... guess!)

Ian

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