Re: What is Content-Length?

On Fri, 12 Dec 1997, Life is hard... and then you die. wrote:

> On Thu, 11 Dec 1997, Scott Lawrence wrote:
> 
> >   There are no transfer encodings in 1.1 for which the length is
> >   ambiguous; we don't need to change the spec now.
> 
> I'm not sure this is true. In the latest draft I discovered the
> following
> in Section 3.6:
> 
>      The Internet Assigned Numbers Authority (IANA) acts as a registry
> for
>      transfer-coding value tokens. Initially, the registry contains the
>      following tokens: "chunked" (section 3.6.1), "identity" (section
> 3.6.2),
>      "gzip" (section 3.5), "compress" (section 3.5), and "deflate"
> (section
>      3.5).
> 
> Two questions:
> 
> 1) Are gzip, compress and deflate really to be used as both transfer
>    encodings and content encodings? What's the rationale behind that?
> 

Yes.  A proxy may wish to compress an object before transmitting it
to a client to improve bandwith utilization or perceived speed.
The proxy can add a transfer encoding, but not a content encoding.

> 2) I'm not very familiar with the details of these encodings, but I
>    believe they aren't self delimiting. Is this true?
> 

I am not sure.  But from the recent discussion it is very clear
that it is cruicially important that all transfer encodings be
explicitly defined to be self-delimiting or non-self-delimiting.
I am not sure this is done in the IANA registry.

John Franks
john@math.nwu.edu