Re: NNTP - how to check for removed newsgroups ?

Char,

>>> Simple question : using the NNTP protocol - How do I check for
>>> newsgroups that have been removed ?

>>There isn't a method defined in any RFC to do so, because there are
>>a number of hurdles that make it infeasible:
>
> Rather than infeasible, it's more likely to be trivial.

Indeed.  Proof on point: the "new newsgroups" command.

>>- *WHO* decides what groups to include on that list?
>
> The user who sits behind the news client or script that provides the
> capability.

:-) The question could be as easily have been about the user as about the 
newsgroup server.  As such my answer was deliberatily as vague, to covered 
both.

But, if its about the user than I, again, refer to the "new newsgroups" 
command, which seems to have solved that problem quite nicely.

>>- How far back do you want to go/removed since *WHEN*?
>
> Since the last time this user performed this check against this server,
> using this client/script.

Simpler answer : since a user-provided date-time.  Like the "new newsgroups" 
command already does.

>>- For each user, the server would need to remember the last time that user
>>  checked the groups, and what groups have been removed since then. 
>> *WHERE*
>>  does the server store this information?
>
> The server would store nothing. The client or local script would store
> everything.

Auric is thinking of a statefull environment where none is required. 
Over-complicating stuff is an occupational hazard to a programmer. :-)

> then it could compare the new file to the old file, diff-like, to see
> what's been added. That much is trivial, and once it does the diff, I
> don't see why there couldn't have been an additional view that shows
> the groups that have been removed since the last check.

My newsgroup reader just flags the new newsgroups in its local list, meaning 
that I can ask for them (long) after they have been added.  Though I have no 
idea what the retaining time (if it works that way) for that "new newsgroup" 
flag is.

> It seems to me that any client that uses a newsrc file could be used as
> the basis for determining which groups are New or Old since the last
> time the command was run.

Aurics suggested to use the LIST commands result for that.

But although that will work, its also rather wastefull to have to download 
all the newsgroups (for me "only" 27,000+ of them - for just one newsgroup 
server) just to be able to do a diff.  Hence the "new newsgroups" command 
was added.  Instead of retrieving thousands of groups (normally) only a 
handfull (if that much) will be returned.

As a test in which I asked for all new newsgroups since January 1, 2023 
(read: a one-and-a-half years worth) I got just 40 of them.

As I recognised the wisdom of that "new newsgroups" command I imagined that 
an "old newsgroups" command could exist for the same reason.

But alas, being able to easily purge old newsgroups seems not to have been 
on anybodies mind. :-(


As for my reason for asking ?   I see way to many newsgroup names that are 
infantile curses at someone (like over 20 containing "sucks" in their 
names).  Assuming that once in a while someone over at the newsgroup server 
goes over all the "newly-added" newsgroups and deletes those I would like to 
get rid of them too (currently I just manually hide them)

Regards,
Rudy Wieser