HTTP callback scheme?
Sat, 22 Dec 2001 23:26:31 -0800
Aren't we overdue for an URI-scheme "httpc" that works
(1) You receive a URL using the scheme, say
(2) You do an HTTP request against that location,
but include a callback address on a header,
for example a real HTTP URL like:
(3) The 'proxy.org' machine actually forwards your
request to some other machine, most likely one
that lacks a public IP address but has kept
an outbound connection open to 'proxy.org'.
(4) That hidden machine considers the request, and
if all goes well does a PUT of content, type
"message/http-response", to your callback
(5) 'proxy.org' returns a trivial OK response code
to indicate the real response is in progress.
- the callback address is just a IP:port pair;
the hidden machine opens the connection but
then immediately pretends the connection was
initiated by the other side -- allowing you
to issue any HTTP request over the connection
- to prevent third parties from pretending to
be the hidden machine, some hash-based
authentication token is passed back through
the request-proxy to the original requestor,
- the hash of what the full response
will be, or
- the hash of some random token, which
the hidden machine will reveal on its
A lot of systems do things a lot like this to get
around firewall/NAT problems -- for example Gnutella's
PUSH request -- but I'm wondering if the approach
has ever been captured in a standardized URI-scheme.
So is this an AlreadyExists or a NeedsToExist?