[Development] QtCS 2017 CoAP session notes

[Thiago Macieira]

== CoAP Client ==

* Contribution consists of CoAP client
** Supports PUT/GET/POST/DELETE
*** Not yet FETCH/PATCH (RFC 8132)
** Supports Blockwise transfer
** Supports Notification (QCoapReply::notified signal, 
QCoapClient::cancelObserve())
** Partially supports multicast
*** Sending on multicast works and works for receiving one reply
*** Currently does not work with receiving multiple replies
* API is modelled after QNAM but does not use it
** QCoapClient, QCoapRequest, QCoapReply
* No DTLS support yet (see network discussion)
* API does support IETF-style resource discovery (multicast GET to /.well-
known/core)
** QCoapClient::discover, QCoapDiscoveryReply
** API needs a little work:
*** signal and parameters
*** discover() should be able to send on both IPv4 and v6 multicast, without 
the user hardcoding anything
*** building of query parameters (QUrlQuery?)
* Add a method to QCoapClient and QNetworkAccessManager: setDeleteOnFinished / 
setAutoDeleteReplies
** Defaults to false on QNAM, defauts to true here
* No CoAP+TCP plans yet

=== Testing ===

* Once we have CoAP server support, we can test client against server
* Inadviseable to run a CoAP server on the Qt network test server
** Network too unstable already in TCP, probably a horrible idea to use it 
with UDP
* We should run a local server on the testing VM
** Californium is Java
** We may need to write something with libcoap (C)

== CoAP server ==

We will need it. For example, ''all'' OCF devices are both clients and 
servers.

== DTLS ==

* DTLS support needs to be added to QtNetwork or it will be too difficult
** We just need to design it so that it will work for both the CoAP client and 
server

== CBOR ==
We would like to have CBOR support in QtCore.
* Would the API be part of QJsonDocument or separate (but looking like it)?
** Thiago's gut feeling is that making it part of QJsonDocument will make it 
too constrained for future uses (Example: COSE uses integer keys in maps, not 
strings)
* Volunteers to work with Thiago on doing this
** Witekio people
** Frederik
** Shawn
** Alexandro

-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center