Re: [paho-dev] non-destructive read

[Peter Niblett <peter_niblett@xxxxxxxxxx>]

Rohit

MQTT is based on a publish/subscribe
concept, where each subscriber/subscription has its own queue of pending
messages. The only way to access that queue via the MQTT protocol is to
connect as that subscriber, and which point the MQTT server will start
trying to deliver the messages to you.  If the messages in question
also match other subscriptions, they will also be being queued up for those
other subscribers, and the fact that they have been delivered to you doesn't
affect those other applications - the messages will still be there waiting
for them when they next connect.

There's one other feature - the Retained
Message.    If someone publishes a message as Retained, that
message will be held on the server and any new subscribers to its topic
will receive a copy of that message. However this isn't really a queue,
since the server only holds the latest Retained message for each topic.

Regards


Peter Niblett
IBM Senior Technical Staff Member



From:      
 Rohit Dhall <dhall.r@xxxxxxx>
To:      
 "paho-dev@xxxxxxxxxxx"
<paho-dev@xxxxxxxxxxx>
Date:      
 08/02/2016 09:26
Subject:    
   Re: [paho-dev]
non-destructive read
Sent by:    
   paho-dev-bounces@xxxxxxxxxxx

---

Hi Kamil,

>>>> What about creating a subscription for the relevant topic
filter(s) and QoS=0? Is that not any good?

This will cause the message to be delivered at most once. Not exactly what
I am looking for. I simply want to browse messages, without impacting their
delivery/consumption by any other application. If MQTT doesn't support
it directly, is there any other way around? 


Regards,
Rohit Dhall
Enterprise Architect, Technology Office-TFG, HCL Technologies
+91-9811181701




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Today's Topics:

   1. Re: non-destructive read (Nicholas O'Leary)
   2. Re: non-destructive read (Kamil Baczkowicz)


----------------------------------------------------------------------

Message: 1
Date: Mon, 8 Feb 2016 08:47:58 +0000
From: "Nicholas O'Leary" <nick.oleary@xxxxxxxxx>
To: General development discussions for paho project
                
<paho-dev@xxxxxxxxxxx>
Subject: Re: [paho-dev] non-destructive read
Message-ID:
                
<CAF=vhqf9QNAx-B8+96CC7ZZw9C=Vaf=H7gqp9mPNVMCZqb=_Ow@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset="utf-8"

Hi,

no, the MQTT protocol does not support that type of operation.

Nick

On 8 February 2016 at 08:42, Rohit Dhall <dhall.r@xxxxxxx> wrote:

> Hi,
>
>
>
> Is there a way, I can browse messages lying on a mosquitto server
> topic, using java, without removing them(non-destructive read)?
>
>
>
> Any help/pointer to the correct APi will be of great help
>
>
>
> Regards,
>
> Rohit Dhall
>
> Enterprise Architect, Technology Office-TFG, HCL Technologies
>
> +91-9811181701
>
>
>
> [image: tfg]
>
>
> ::DISCLAIMER:: The contents of this e-mail and any attachment(s) are
> confidential and intended for the named recipient(s) only. E-mail
> transmission is not guaranteed to be secure or error-free as 
> information could be intercepted, corrupted, lost, destroyed, arrive
> late or incomplete, or may contain viruses in transmission. The e
mail 
> and its contents (with or without referred errors) shall therefore
not 
> attach any liability on the originator or HCL or its affiliates. Views
> or opinions, if any, presented in this email are solely those of the
> author and may not necessarily reflect the views or opinions of HCL
or 
> its affiliates. Any form of reproduction, dissemination, copying,
> disclosure, modification, distribution and / or publication of this
> message without the prior written consent of authorized representative
> of HCL is strictly prohibited. If you have received this email in
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Message: 2
Date: Mon, 8 Feb 2016 09:16:20 +0000
From: Kamil Baczkowicz <kamil.baczkowicz@xxxxxxxxx>
To: General development discussions for paho project
                
<paho-dev@xxxxxxxxxxx>
Subject: Re: [paho-dev] non-destructive read
Message-ID:
                
<CAHtMjFr928Do+uWSZoEqPq5UFrdd17ykoko+e1gwERrQ1emp-w@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset="utf-8"

Hi,

What about creating a subscription for the relevant topic filter(s) and
QoS=0? Is that not any good?

Kamil

On Mon, Feb 8, 2016 at 8:42 AM, Rohit Dhall <dhall.r@xxxxxxx> wrote:

> Hi,
>
>
>
> Is there a way, I can browse messages lying on a mosquitto server
> topic, using java, without removing them(non-destructive read)?
>
>
>
> Any help/pointer to the correct APi will be of great help
>
>
>
> Regards,
>
> Rohit Dhall
>
> Enterprise Architect, Technology Office-TFG, HCL Technologies
>
> +91-9811181701
>
>
>
> [image: tfg]
>
>
> ::DISCLAIMER:: The contents of this e-mail and any attachment(s) are
> confidential and intended for the named recipient(s) only. E-mail
> transmission is not guaranteed to be secure or error-free as 
> information could be intercepted, corrupted, lost, destroyed, arrive
> late or incomplete, or may contain viruses in transmission. The e
mail 
> and its contents (with or without referred errors) shall therefore
not 
> attach any liability on the originator or HCL or its affiliates. Views
> or opinions, if any, presented in this email are solely those of the
> author and may not necessarily reflect the views or opinions of HCL
or 
> its affiliates. Any form of reproduction, dissemination, copying,
> disclosure, modification, distribution and / or publication of this
> message without the prior written consent of authorized representative
> of HCL is strictly prohibited. If you have received this email in
> error please delete it and notify the sender immediately. Before 
> opening any email and/or attachments, please check them for viruses
and other defects..
>
> _______________________________________________
> paho-dev mailing list
> paho-dev@xxxxxxxxxxx
> To change your delivery options, retrieve your password, or 
> unsubscribe from this list, visit 
> https://dev.eclipse.org/mailman/listinfo/paho-dev
>
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------------------------------

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