RE: Binary XML

[Michael Brennan <Michael_Brennan@allegis.com>]

I'm not aware of any limitation sending binary content through port 80. I've
done it plenty of times without problems. I would imagine, though, that an
HTTP request (or response) that fails to properly identify it's media type
might be mangled by an intermediary. Perhaps someone with deeper protocol
understanding than myself might wish to comment, though.

HTTP is MIME-like in that it supports a number of standard MIME headers (and
a few of its own). No special MIME wrapper is needed. Just specify the
appropriate Content-Type header. Intermediaries are free to interpret and
alter text content (e.g. Content-Type: text/xml), but are in violation of
the spec if they interpret or alter non-text content (e.g. Content-Type:
application/zip). Also, you can employ binary compression so long as you
properly identify the protocol used via the Content-Encoding header. (It's
also legal to use Content-Transfer-Encoding for this, but I think
Content-Encoding has broader support in applications, at present. Both IE
and Netscape, for instance, will properly recognize gzip-compressed data if
the HTTP message includes "Content-Encoding: gzip".)

You can also use MIME multipart formats to transmit multiple documents over
HTTP in one message. This is another area, though, where you run the risk of
being incompatible with other tools. However, in the XML messaging world,
the SOAP w/ Attachments spec and ebXML have given some momentum to use of
multipart/related wrappers over HTTP, so the level of support for this is
rapidly increasing.

> -----Original Message-----
> From: Stuart Naylor [mailto:indtec@eircom.net]
> Sent: Thursday, July 26, 2001 2:10 PM
> To: 'Michael Brennan'
> Cc: xml-dev@lists.xml.org
> Subject: RE: Binary XML
> 
> 
> I thought the only way you could get binary through port 80 
> is in a mime
> wrapper. This gives it a layer of encapsulation in a effort 
> to render it
> safe.
> 
> Port 80 is text only even if you can hide binary in wrapper 
> it still is
> a text tranfer but how would this work with binary xml.
> Would this also be included in a wrapper so we have a unicode protocol
> represented as binary then wrapped in a mime type to be unwrapped so
> that processing can occur ?