Chunked Encoding (Was: very weird sitemap error handling behavior)

[Santiago Gala <sg...@hisitech.com>]

Nicola Ken Barozzi wrote:
(...)
 >
 > You came up with clever ideas about resetting via HTTP or something
 > like that (chunking?) but I'm not able to understand a thing about
 > it.
 >

 From http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html

 > The chunked encoding modifies the body of a message in order to
 > transfer it as a series of chunks, each with its own size indicator,
 > followed by an OPTIONAL trailer containing entity-header fields. This
 > allows dynamically produced content to be transferred along with the
 > information necessary for the recipient to verify that it has
 > received the full message.

This will allow Cocoon to start "pipelining" a valid response to the 
client, in chunks of server controlled size, and use the optional final 
trailer:

 > The trailer allows the sender to include additional HTTP header
 > fields at the end of the message.
 >

at the end, for instance for incremental computation of the 
Content-Length or MD5, for instance.

WRT using the trailer for error handling, it puzzles me if there is any 
way to do it as chunked transfer encoding does *not* allow changing the 
status code. It is intended as a "latency killer" feature, and also to 
enable computation of length and md5 without having to cache the whole 
answer. It would be great in the "proxy friendly" thread, though.

Regards,
      Santiago