[Juser] XMPP newbie is very confused

[Florian Schmaus]

Hi there, :)

it appears that your computer's time/date is not correct (or maybe I am 
replying to a very old mail).

On 29/12/2020 20.15, deletestuff9 at msn.com wrote:
>   1. Are all the contacts and messages in my conversations stored on the
>      server that my XMPP account was created on?

Contacts (the "roster") are stored on the server.
For messages it depends on weather or not your server provided this 
feature (e.g., XEP-313 Message Archive Management) and his it enabled. 
Most modern XMPP server setups provide it, though.


>   2. If the answer to #1 is "Yes", how long do they exist on that server?

That's also a configuration parameter your server operation can set.


>   3. If the answer to #1 is "Yes", how do I permanently delete contacts
>      on the server?  How do I permanently delete selected messages within
>      a single conversation from the server?

Contact operations like, adding, renaming, and deleting, are typically 
done via your XMPP client. Deleting messages too, although this feature 
is maybe not so widespread.


>   4. Using a web browser tool like Movim, if I add or delete a contact,
>      are those changes then reflected on the server?
>   5. Using a web browser tool like Movim, it lets me "retract" a
>      message.  Is that the same as deleting that message on the server?

I think those are best answered by someone from Movim.


>   6. If I use a desktop tool like Dino, do the contacts and conversations
>      it shows exist on the desktop computer's hard drive in addition to
>      existing on the server?

Yes, clients will typically hold a copy of the roster on local storage 
and sync only the differences upon connecting.


>   7. Using a desktop tool like Dino, if I delete a contact, is that
>      contact and the associated conversation deleted from the server?

I'd expect that the contact is removed from the roster, but the messages 
stay in the user's message archive (unless there is an explicit option 
to delete those as well).


>   8. Using a desktop tool like Dino, if I delete a contact, is that
>      contact and the associated conversation deleted from the desktop
>      computer's hard drive, or merely no longer displayed in the 
> application?

That is up to the XMPP client implementation. So maybe some Dino 
developer can answers those.


>   9. If I use an android app like Conversations, do the contacts and
>      conversations it shows exist on the android device in addition to
>      existing on the server?
Mobile clients may restrict the amount of data that is stored locally 
due computation and storage limitations. This is no problem for the 
roster, but message archives can become quite large. Again, the actual 
behavior depends on the implementation. So…

> 10. If I use an android app like Conversations, if I delete a contact
>      and/or a conversation, are that contact and the associated
>      conversation deleted from the server?
> 11. If I use an android app like Conversations, if I delete a contact
>      and/or a conversation, are that contact and the associated
>      conversation deleted from the android device, or merely no longer
>      displayed in the app?

…maybe some Conversation developer can answers those.


> 12. Basically, I'm trying to understand all the places my contacts and
>      messages exist (server, desktop, android); how I can permanently
>      delete them when I want to (which clients will accomplish that), and
>      what kind of synchronization I can expect when I make a change on
>      one device and its client with all other devices and clients and the
>      server.
> 13. The terminology is also confusing and not explained:  Movim talks
>      about "retracting" messages; Conversations talks about "clearing
>      messages"; are those doing the same thing?  Are they deleting
>      messages or something else?

Those are very valid points. We definitely can do better here, to make 
the user aware of the consequences of those actions. From a technical 
point of view, retraction is usually the act of sending a subsequent 
message that tells the recipient that a previous message is now 
"retracted". Usually this comes with the disclaimer that there is now 
way for to force the recipient to actually delete the message. 
Furthermore, if the message will also get deleted in all archives can 
also not be guaranteed. That's basically due the decentralized 
architecture of XMPP.

Hope this helps.

- Florian

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