Subject: RE: [lemonade] Channel updates for content conversion

From: [email-masked]
Date: Wed, 24 Nov 2004 17:46:54 -0600

> -----Original Message-----
> From: ext Lyndon Nerenberg [mailto:[email-masked]]
> Sent: Tuesday, November 23, 2004 11:08 PM
...
> --On 2004-11-23 9:24 AM -0600 [email-masked] wrote:
> 
> > How do you communicate that a conversion between top level
> > media types is permitted? For example from pdf to plain
> > text.
> 
> Advertise text/plain as a target conversion type.

I think of conversion as a function with a Domain and Range.
CHANNELCONVERSIONS returns the Range. You seem to be assuming
the Domain to be the universe of all content types, which is 
reasonable. How do I know what the mapping is? For example 
the following conversion makes no sense:

Convert(application/pdf) = audio/basic

Mike

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---

From: Lyndon Nerenberg <[email-masked]>
Date: Thu, 25 Nov 2004 09:49:23 -0800

--On 2004-11-24 5:46 PM -0600 [email-masked] wrote:

> reasonable. How do I know what the mapping is?

The client is assumed to know about the conversions it is performing. 
E.g. one assumes that a reasonable client won't ask a server to convert 
audio/basic to text/plain.

Enumerating the list of all possible transformations is potentially 
very verbose. And even with the list, the client still has to make an 
intelligent decision about the transformation. You have to assume some 
intelligence on the part of the client. If it's presented with an 
image/jpeg and cannot handle the JPEG format, but can display GIF, then 
the presence or absence of 'image/gif' in the CHANNELCONVERSIONS output 
is a strong hint that the conversion will work. If the client asks to 
convert that image/jpeg to a text/plain, it deserves what it gets. (A 
NO response.)

> For example

And the server would return a tagged NO response, since it is unable to 
perform the requested conversion.

--lyndon