Non standard 100-continue behaviour

[David Hadas]

RFC 2616 indicates:
 The purpose of the 100 (Continue) status (see section 10.1.1) is to allow a client that is sending a request message with a request body to determine if the origin server is willing to accept the request (based on the request headers) before the client sends the request body. In some cases, it might either be inappropriate or highly inefficient for the client to send the body if the server will reject the message without looking at the body.
...
      - A client MUST NOT send an Expect request-header field (section 14.20) with the "100-continue" expectation if it does not intend
        to send a request body.

Swift proxy server, when communicating with the back-end servers ALWAYS sends 100-continue. Even if the length headers indicate that there is no body (content-length: 0). This behavior is not inline with the standard.
As a minimum, swift must avoid sending 100-continue for PUT requests without a body (content-length is zero).
It is highly desired that the swift would also avoid sending 100-continue for any objects below some threshold (e.g. 64K)
Alternatively, this threshold may be configurable.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/14663

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/14663
Committed: http://github.com/openstack/swift/commit/6c6b84b3f5297128b277b0f20c70919250843ae3
Submitter: Jenkins
Branch: master

commit 6c6b84b3f5297128b277b0f20c70919250843ae3
Author: David Hadas <email address hidden>
Date: Tue Oct 23 10:07:53 2012 +0200

    Fix non standard 100-continue behaviour

    Swift proxy server, when communicating with
    the back-end servers ALWAYS sends 100-continue.
    Even if the length headers indicate that there
    is no body (content-length: 0).
    This behavior is not inline with the standard.
    RFC2616:8.2.3 disallows 100-continue
            for req.content_length==0

    This fix removes 100-continue during PUT requests
    without a body while maintining the ability for
    handoff in case of faliure.

    On branch bp/wsgi-application-interface-5
       modified: swift/proxy/controllers/obj.py

    Fixes: Bug #1070025
    Implements Blueprint: wsgi-application-interface

    Change-Id: Ia4eb8b886a74968cca4e8bde208641b37f2c104c