[Interest] Q_PROPERTY notification across processes?

[Constantin Makshin]

Oh, yes, you're right. I was confused by the "Introduction to D-Bus"
section of the D-Bus web site, probably some parts of it are too outdated.
Sorry for spreading that confusion. :-)
On May 17, 2013 1:42 PM, "Mandeep Sandhu" <mandeepsandhu.chd at gmail.com>
wrote:

>
> On Fri, May 17, 2013 at 9:55 AM, Constantin Makshin <cmakshin at gmail.com>wrote:
>
>> Charley said that in most cases his applications will be run on different
>> computers, so D-Bus won't help him since it doesn't work over network.
>>
> DBus can work over the network. You just need a to specify a network
> address instead of a local one for DBus communications. Though I'm not sure
> about portability to other platforms as DBus is primarily used in Linux
> based systems (I'm not sure about it's support on Windows). CMIIW.
>
> Regards,
> -mandeep
>
>
>
>> On May 17, 2013 8:01 AM, "Tony Rietwyk" <tony at rightsoft.com.au> wrote:
>>
>>> Hi Charley, ****
>>>
>>> ** **
>>>
>>> You didn't say which type of systems this will be running on? ****
>>>
>>> ** **
>>>
>>> What about QtDBus using a direct connection between the applications,
>>> instead of the system-wide bus?  ****
>>>
>>> ** **
>>>
>>> Even if that doesn't work for you, it has solved many of the same
>>> problems, and needed over 20,000 lines of code! ****
>>>
>>> ** **
>>>
>>> Regards, ****
>>>
>>> ** **
>>>
>>> Tony****
>>>
>>> ** **
>>>
>>> ** **
>>>
>>> *From:* interest-bounces+tony=rightsoft.com.au at qt-project.org [mailto:
>>> interest-bounces+tony=rightsoft.com.au at qt-project.org] *On Behalf Of *Charley
>>> Bay
>>> *Sent:* Friday, 17 May 2013 11:27 AM
>>> *To:* Qt Interest
>>> *Subject:* [Interest] Q_PROPERTY notification across processes?****
>>>
>>> ** **
>>>
>>> I have a C++ QObject-derived class that exposes properties for use in
>>> QML, works fine (Qt5).****
>>>
>>> ** **
>>>
>>> WHAT I WANT:****
>>>
>>> ** **
>>>
>>> I would like to instantiate an "instance" of this class in each of two
>>> processes, where changes in one "notifies" the other (in the other
>>> process).  This is logically something like "local-instance-reflection" to
>>> a remote instance in a remote process.****
>>>
>>> ** **
>>>
>>> (I could create a second class-type if needed, but current
>>> implementation suggests I could instantiate the same class type on each
>>> side.)****
>>>
>>> ** **
>>>
>>> My current thoughts are to use a "socket" between the two processes,
>>> where the objects "agree" on a unique identifier that represents that
>>> "reflected-instance" in each process.  Then, the implementation would
>>> trigger "onChange" operations in the remote-instance from property-changes
>>> in the local-instance.  There would be many of these "reflecting-pairs".
>>> ****
>>>
>>> ** **
>>>
>>> This "implementation-plumbing" would probably be through some C++
>>> implemented dispatcher, where one would be instantiated in each process,
>>> and be responsible for the serialization for state-changes/notifications
>>> between the processes (read/write), and routing the notification to the
>>> object in the local process.****
>>>
>>> ** **
>>>
>>> A concern I have is that there will be *many* of these pairs (thousands,
>>> possibly tens-of-thousands), and I don't know if the approach would
>>> scale-well for lots of notifications.****
>>>
>>> ** **
>>>
>>> Does this design seem reasonable?****
>>>
>>> ** **
>>>
>>> Do you have thoughts on an alternative?****
>>>
>>> ** **
>>>
>>> It seems like the "Q_PROPERTY" notification through QML would be an
>>> interesting mechanism to enable this "generic-cross-process"
>>> event-based-synchronization.****
>>>
>>> ** **
>>>
>>> I can't use shared memory, as these processes will typically be on
>>> different machines.****
>>>
>>> ** **
>>>
>>> --charley****
>>>
>>> ** **
>>>
>>> _______________________________________________
>>> Interest mailing list
>>> Interest at qt-project.org
>>> http://lists.qt-project.org/mailman/listinfo/interest
>>>
>>>
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