Re: Distinguishing 0-byte request body in HTTP/2

Hi Kazuho,

On Thu, Sep 15, 2016 at 09:09:42AM +0900, Kazuho Oku wrote:
> Hi,
> Thank you very much for the clarification.
> So to paraphrase, the general rule for handling request body is
> defined in section 3.3.3 of RFC 7230 as:
>    6.  If this is a request message and none of the above are true, then
>        the message body length is zero (no message body is present).
> which means that in HTTP, there is no distinction between a request
> with zero-length body and a request _without_ a body.
> That means it is completely up to the HTTP client to whether or not to
> send `content-length: 0` for such requests, though each implementation
> may decide to send or not, depending on interoperability issues that
> might exist.

In fact there exists a corner case, some servers return 411 in response
to a POST without a content-length. Thus I'd suggest that the client
always emits the content-length when it considers that semantically it
emits a body even if it's empty. Let's imagine a disk backup tool uploading
files over HTTP, using a few header fields to pass file name, permissions
and various meta-data. Some files may be empty, and regardless of this they
are sent. In this case it totally makes sense to emit "content-length: 0".

I'd be tempted to simplify this as "if you're sending a body even an empty
one, announce its size in content-length". Methods like POST and PUT expect
a message body so that should always be done.


Received on Thursday, 15 September 2016 07:00:29 UTC