Re: Tentative File Open & Safe Save

On 1/24/25 2:08 PM, Rich wrote:

186282@ud0s4.net <186283@ud0s4.net> wrote:

On 1/23/25 7:39 PM, Lawrence D'Oliveiro wrote:

When developing an app, saving changes that a user has made to a document
needs to be managed carefully. Simply overwriting the existing file with
the new data can cause trouble, if your app (or the system) should crash
part-way through, because then the file ends up with some part of the old
document overwritten with the new one, and so the user ends up without a
valid copy of either the old or the new version -- in effect, all their
work is lost.
>

>
   Of course systems CAN glitch at any time, often for
   totally mysterious reasons - power maybe, minor
   coding error only hit 1:1000 times, cosmic rays ....
   so if yer stuff is SUPER important, like tax docs
   or whatever .......

 Third option:
 Use a Sqlite file as the "file" the app uses, and delegate all the ugly
aspects of atomic file "adjusting" and "storing" to Sqlite (which by
now has mitigations for issues most individual developers will never
see nor hear of).
 Plus, a Sqlite file would allow a very easy "versioned file" setup as
well.
 Downside: one has to have an Sqlite module for one's language availble,
or one has to include Sqlite's driver in one's app.

   I looked into this a bit ... it's a potential solution,
   but seems, well, a little TOO for the issue at hand.
   If using Word or Excel, the system continually creates
   temp files of every little change every X minutes. My
   bitch is that sometimes if FORGETS to delete all those
   files after (had to add a filter to my backup pgms) - but
   I'm not bitching about the CONCEPT.
   Basically ANY programming language allows easy use of
   that particular kind of solution. No add-ons needed.
   Let's say I'm a fan of "KISS" solutions.
   A concern is systems that update ALL OF THE TIME like
   databases. Keeping in-transaction copies of every little
   file is less fun. Totally do-able, and oft is, but
   less fun. Multi-user record-only-locked files makes
   it even more less fun.
   But, alas, abrupt crashes/lockups or user madness is
   STILL a real problem so SOMETHING has to be done.
   Computers are machines, and machines fuck up and/or
   CAN be fucked-up.