An alternative might be some form of transaction memory.
When a tiddler is served over a network it has last-modified time (this is
the time when the server
last stored a modification)
If a user edits a tiddler and sends it back it should include this time.
Call this Told.
When the server receives an updated tiddler it checks to see if Told
is identical to the current last modified time of the tiddler if so the
update
succeeds.
If the two are not identical the update fails - and the user is told that
their new tiddler value is not an update to the latest value of the tiddler.
They should then get the latest version and resolve any conflicts.
This works pretty well if we make a couple of assumptions
1) people do not edit the same tiddlers at the same time
2) edits are relatively quick
This way nothing gets locked and there are no checkins/outs.
Actually, each tiddler could be (internally) a write-append-only log of
diffs
this way no data gets lost and we can back up to any old value.
Cheers
/Joe
On Wednesday, 23 January 2019 01:50:01 UTC+1, TonyM wrote:
>
> Folks,
>
> I have raised this a number of times in a number of contexts but *NOW I'm
> Serious - We need Check in and Check Out*
>
> TWC had a method to allow serial editors and a lock file (that all can
> see). We need this as an option to TW5 as well.
>
> Why?
>
> 1. TiddlyWikis can be used as smart documents served from a file or
> network location without fear of contention and overwrite (Single File or
> Network served)
> 2. Its a "poor mans" multi-user wiki - Serial multi-user update access
> NOT Multi-user multi-access
> 3. TW-Receiver could provide read/update access to any number of users
> knowing simultaneously is not available.
> 4. The lack of such a facility is driving some of the complexity we
> face trying to simplify the saving process, if we could check in out
> documents reliably we secure the the wiki from corruption/overwrite.
> 5. It could help users protect them from themselves opening the same
> wiki from more than one tab/or browser without needing a server solution.
> 6. Perhaps TiddlyDesktop and the other servers could also honour this
> allowing free transfer between platforms.
>
> How
>
> I am confident we have the technology and avenues by which to achieve
> this, I do not believe their is a technical barrier any more. An example in
> point is some of the local save tools, we know they are writing information
> such as backups, so we have the ability to read and write a switch/lock and
> we can include an informational user name in that switch.
>
> We could provide a checked out to current user with a save and check in
> button. We could provide a NO check out user with a reload and check in
> button (if not locked)
>
> I can provide more technical possibilities if requested, but some of you I
> expect already know how to do this.
>
> Feedback please!
>
> Thanks tony
>
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