Re: [iot-wg] Questions regarding MQTT/Paho

[Jens Reimann <jens.reimann@xxxxxxxxxxxxxxx>]

Hello Ian,

oh I even was not aware of the fact that events are not sent when the
connections is broken. I thought thats what the persistence stuff was for.

The bug description looks good for me. Thanks for adding it!

Jens

On 07/30/2014 11:55 AM, Ian Craggs wrote:
> Hi Jens,
>
> thanks for the comments.  We are open to suggestions and contributions
> to improve the clients of course.  A frequently asked for capability
> is to send messages when the client is disconnected ("offline
> buffering") - it seems to me that these two improvements are related.
>
> It seems to me what you are asking for is a simple reconnect using the
> same connect options until the application calls disconnect. There
> would be some parameters (reconnect interval/backoff).  I've raised a
> bug (https://bugs.eclipse.org/bugs/show_bug.cgi?id=440734) to track
> the suggestion.  Please feel free to add more information there.
>
> Ian
>
>
> On 07/30/2014 08:38 AM, Jens Reimann wrote:
>> Hello Ian,
>>
>> thanks for the answer.
>>
>> I totally understand the reason for passing through the protocol
>> specific to a simple API. And it is important to have this control.
>>
>> However, now I fully understand when you bang your head on the table
>> ;-), "I just want to push some data to MQTT".
>>
>> No I would guess that there are some "common ways to do it" and which
>> get repeatedly implemented by users. So instead of everybody
>> re-implementing these common cases, it would simply be nice to have
>> these coming from the MQTT library.
>>
>> Actually In Eclipse SCADA we have the some issue. Connections simply
>> inform you about the state, but the "AutoReconnectController" keeps the
>> session open as long as requested.
>>
>> Anyway, thanks for the help. So I now know that I have to do it
>> myself ;)
>>
>> Jens
>>
>> On 07/29/2014 03:15 PM, Ian Craggs wrote:
>>> Hi Jens,
>>>
>>> what Benjamin says is correct.  It is a manual step to reconnect in
>>> the callback.  This is for a number of reasons.
>>>
>>> 1.  MQTT is defined as a protocol rather than an API, so the APIs have
>>> been written to be close to the behaviour of MQTT.  This makes it easy
>>> to understand the APIs in the context of MQTT, and provides maximum
>>> flexibility.
>>>
>>> 2. Depending on the connect options used, will message or clean
>>> session for instance, disconnection and reconnection can have effects
>>> which you need to know about and/or control.  You may want to change
>>> connect options when you reconnect, or delay reconnection.  To allow
>>> all these combinations on automatic reconnection would require a
>>> complicated API.
>>>
>>> Ian
>>>
>>> On 07/25/2014 02:08 PM, Benjamin Cabé wrote:
>>>> Hi Jens,
>>>>
>>>> I think you may want to post this question on the paho-dev mailing
>>>> list (I
>>>> cross-posted there)!
>>>> My understanding though is that when the MqttCallback#connectionLost()
>>>> method is called, it's up to you to decide whether you want to
>>>> reconnect
>>>> or not.
>>>>
>>>> Benjamin.
>>>>
>>>>
>>>> Le 25/07/2014 14:47, « Jens Reimann » <jens.reimann@xxxxxxxxxxxxxxx> a
>>>> écrit :
>>>>
>>>>> Hi,
>>>>>
>>>>> maybe somebody can give me a short hint about the MqttAsyncClient
>>>>> from
>>>>> Paho.
>>>>>
>>>>> I found the javadoc, and know how to connect and disconnect. What I
>>>>> don't know is, what will happen when the connection breaks. Does it
>>>>> automatically re-connect, or is this a "manual" step?
>>>>>
>>>>> Thanks for helping
>>>>>
>>>>> Jens
>>>>>
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