Chunked Encoding

[Ian Price <ianprice90@googlemail.com>]

Hi guilers,

If you've used the (web ...) modules, you may have noticed that guile
does not currently support chunked-encoding. This is expected in a
HTTP/1.1 world, so I wrote an implementation to cover my immediate
need, but I'm not particularly convinced of it, so I wanted to discuss
this before sending a patch.

What I did was introduce two new exported procedures for reading (all I
needed at the moment), namely 'read-chunk' and 'read-chunked-response-body'.

  (read-chunk port)
  reads one chunk from a port.

  (read-chunked-response-body response)
  read the full body for the response and returns it as a bytevector. It
  was written to be similar to 'read-response-body'.

For writing chunks then, the obvious thing is to write two procedures
'write-chunk' and 'write-chunked-response-body' which perform the
inverse. However, it seems to me that 'write-chunked-response-body' is a
practically useless procedure, because if you ever had a full body, you
can just use 'write-response-body'.

Another option I've been thinking over would be to go for a sort of
chunking version of R6RS' 'transcoded-port' which would handle it
transparently for users of the returned port.

I'd also suggest extending 'http-get' from (web client) to handle
chunked encoding (and trailers too, I guess) for the user.

Comments kindly requested,
Ian

-- 
Ian Price

"Programming is like pinball. The reward for doing it well is
the opportunity to do it again" - from "The Wizardy Compiled"