[Netconf] usage of HTTP in restconf-notif-07

[Martin Bjorklund <[e-mail]>]

Hi,

I think the -07 version is a step in the right direction for this
draft.  But I have a comment on the usage of HTTP/2.

I am not an expert at all in HTTP/2, but I wonder if the way this
draft uses it is correct.  The draft is very short on details, but
essentially says that the client POSTs to the "uri" that the server
returns (probably w/o a body?), and then that the server sends
individual notifications in DATA frames.  Is this really legal?  RFC
7540, section 8 says:

   HTTP/2 is intended to be as compatible as possible with current uses
   of HTTP.  This means that, from the application perspective, the
   features of the protocol are largely unchanged.  To achieve this, all
   request and response semantics are preserved, although the syntax of
   conveying those semantics has changed.

It seems to me that the restconf-notif draft violates this paragraph.

In fact, it seems that what the draft tries to do is more or less
exactly the same as SSE, except w/o the details, e.g., it doesn't
specify the content-type.

It also seems to me (after some googling) that it is perfectly fine to
use standard SSE with HTTP/2, and that's what people are using to
deliver server-generated events/notifs to clients with HTTP/2.

So, this draft should probably not mention HTTP/2 at all, but instead
just specify the semantics of the "uri" resource and how a client can
POST to it to get SSE going.  The draft should the refer to section
6.4 of RFC 8040 for how notifications are sent from this resource.


/martin