Re: [hono-dev] CoAP protocol adapter for Hono

["Hudalla Kai (INST/ECS4)" <kai.hudalla@xxxxxxxxxxxx>]

On Thu, 2018-03-08 at 15:31 +0100, Alfusainey Jallow wrote:
> Hi Kai,
> 
> Thanks much for the response!
> 
> > I think I do not understand the question. Can you be a little more specific?
> 
> I was just wondering what coap-base back-end system will the coap adapter
> communicate with. Assume we have a coap device A that wants to send telemetry
> data downstream, do we have the ff. flow:
> 
> A -> coap Adapter -> Hono Messaging -> coap-base server -> business
> application. Will Hono messaging send the data through a coap-base network down
> to the business apps?
> 
No, the protocol adapters' purpose is to normalize all messages to AMQP 1.0.
Thus, the flow of messages through the system is as follows:

A -> CoAP Adapter -> Hono Messaging -> AMQP 1.0 Messaging Network -> business
application.

Note that it is analogous to any other protocol adapter, e.g. for the MQTT
adapter we get:

A -> MQTT Adapter -> Hono Messaging -> AMQP 1.0 Messaging Network -> business
application.

This way, a downstream business application does not need to bother about the
particular transport protocol used by the device. It will always consume messages
using AMQP 1.0.

> > as long as it uses the API as intended, right?
> 
>  
> Yes, that makes perfect sense!
> 
> cheers
> 
> 2018-03-08 8:37 GMT+01:00 Hudalla Kai (INST/ECS4) <kai.hudalla@xxxxxxxxxxxx>:
> > Hi Alfusainey,
> > 
> > thanks for your interest in contributing to the Hono project :-)
> > 
> > I have made some inline comments below
> > 
> > --
> > Mit freundlichen Grüßen / Best regards
> > 
> > Kai Hudalla
> > Chief Software Architect
> > 
> > Bosch Software Innovations GmbH
> > Ullsteinstr. 128
> > 12109 Berlin
> > GERMANY
> > www.bosch-si.com
> > 
> > Registered Office: Berlin, Registration Court: Amtsgericht Charlottenburg;
> > HRB
> > 148411 B
> > Chairman of the Supervisory Board: Dr.-Ing. Thorsten Lücke; Managing
> > Directors:
> > Dr. Stefan Ferber, Michael Hahn
> > 
> > On Wed, 2018-03-07 at 12:10 +0100, Alfusainey Jallow wrote:
> > > Hi hono-devs,
> > >
> > > I am interested to provide CoAP protocol adapter support for Hono as part
> > of
> > > GSoC '18. I am a PhD student (in the preparatory phase) at Saarland
> > University
> > > (Germany).
> > >
> > > I have an interest in contributing to opensource and started doing so for
> > the
> > > Apache Jackrabbit project in 2014. The reason for choosing an Eclipse
> > project
> > > for my GSoC is that I have been using the Eclipse IDE for all my Java
> > projects
> > > and want to use this opportunity to contribute back to the community.
> > >
> > > For Apache Jackrabbit, I implemented a missing feature within the client-
> > > server-based implementation of JSR 283[1] present with Apache
> > Jackrabbit[2].
> > > While the reference implementation already provided support for access
> > control
> > > management, as defined by the specification (JSR 283), this was outstanding
> > in
> > > the "JCR Remoting"[3]. My contribution was to fill that gap and the end
> > result
> > > was appreciated by the community[4].
> > >
> > > I have forked the Hono and Californium repositories and already have my
> > > development environment setup. I looked at the Hono Protocol Adapter base
> > class
> > > and studied how the Http protocol adapter was implemented as an extension
> > to
> > > the base protocol adapter. Concretely, I looked at how the implementation
> > was
> > > tested by going through the
> > > org.eclipse.hono.adapter.http.AbstractVertxBasedHttpProtocolAdapterTest and
> > > org.eclipse.hono.adapter.http.vertx.VertxBasedHttpProtocolAdapterTest unit
> > > tests.
> > >
> > well done
> > 
> > > I also spent sometime experimenting with a custom HTTP protocol adapter as
> > > described in [5]. For californium, I started the HelloWorldServer and use
> > the
> > > copper firefox add-on as a client to interract with the server.
> > >
> > > I just have few questions:
> > > 1. Should the coap adapter be built on top of Californium i.e use it as a
> > > library?
> > 
> > Yes, absolutely. We would also like the protocol adapter be built on vert.x,
> > i.e.
> >  derived from AbstractProtocolAdapterBase
> > 
> > > 2. Who will be the consumer of the API exposed by the coap adapter, IoT
> > devices
> > > only?
> > 
> > At least, that's what we have in mind for the protocol adapters. However, we
> > cannot really determine whether the client is an IoT device or not, as long
> > as it
> > uses the API as intended, right?
> > 
> > > 3. Where on the stack will the CoAP server sit on? Or do we not care?
> > >
> > 
> > I think I do not understand the question. Can you be a little more specific?
> > 
> > > I look forward to this fun project and any further advice/tips on what I
> > should
> > > do next would be appreciated.
> > >
> > > [1] https://jcp.org/en/jsr/detail?id=283
> > > [2] http://jackrabbit.apache.org/jcr/index.html
> > > [3] https://issues.apache.org/jira/browse/JCR-2113
> > > [4] http://jackrabbit.510166.n4.nabble.com/ANN-Master-Thesis-by-Alfusainey-
> > Jall
> > > ow-on-Apache-Jackrabbit-td4662126.html
> > > [5] https://www.eclipse.org/hono/dev-guide/custom_http_adapter/
> > >
> > >
> > > Kind regards
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> 
> 
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