Getting/setting group parameters/info from backends.

Getting/setting group parameters/info from backends.

[visigoth]

So--I've been poking around, and there doesn't seem to be any sort of
reasonable interface to perform this function.  (Well--this isn't
entirely true.  We have the nnchoke-request-update-info function that
I'm going to make use in nnimap, but I've looked at what gets done,
and it's not good enough.  It's good from the point of view of Gnus
retrieving information from back-ends.  It does that just fine.  But
when my nnimap code needs to know the base-uid chunk of information,
or set it, Gnus isn't calling the update-info function.

So--what I'd like to find is some method for a back-end to ask for
and/or manipulate the group info at any point it wants to.
Specifically, if that's a problem, I need access to read group-info
-before- Gnus does an nnimap-request-group, because I need to have
that number to calculate the results.

If at all possible, it would be nice to also shove data into that
location when it is available, rather than waiting for the next time
Gnus thinks to ask.

I'm not sure exactly how this should work.  When a back-end asks for
information, it somehow has to identify exactly the group it's asking
for.  What if two servers on one backend have the same group name?
Can you have multiple servers connecting to one machine?  Perhaps this
is somehow related to group parameters.  In any case, I'm unsure how
to explicitly let Gnus know who I am.

The list appears to be down for now--but I look forward to input when
it comes back up.  I'm very happy to have nnimap working at all, but
it's only most of the way there.  Without UID stuff, things could get
very icky.

I'm off to bed now.  I expect when I get back to my code I'll have
nnimap work with its own group->UID mappings, and maybe save it
separately.

John.

Re: Getting/setting group parameters/info from backends.

[Lars Magne Ingebrigtsen]

visigoth@naiad.fac.cs.cmu.edu writes:

> So--what I'd like to find is some method for a back-end to ask for
> and/or manipulate the group info at any point it wants to.
> Specifically, if that's a problem, I need access to read group-info
> -before- Gnus does an nnimap-request-group, because I need to have
> that number to calculate the results.

Why do you need to store that information in the group info?  Most
other backends store information they need in separate files.  I
realize that this may be a pain to do with IMAP, since that would make
things much less portable, but can't you store that in a special
folder on the IMAP server or something?  (I know nothing about IMAP,
so just bonk me on the head if I'm raving here...)

> I'm not sure exactly how this should work.  When a back-end asks for
> information, it somehow has to identify exactly the group it's asking
> for.  What if two servers on one backend have the same group name?

The nntp backend just has `nntp-current-group' that says what the
current group is.  The nnoo stuff will switch between various virtual
servers for you, so that's no problem.

> Can you have multiple servers connecting to one machine? 

If you want to, I guess.

> The list appears to be down for now--but I look forward to input when
> it comes back up. 

Has it been down?  Eeek!

-- 
(domestic pets only, the antidote for overdose, milk.)
  larsi@ifi.uio.no * Lars Ingebrigtsen

Re: Getting/setting group parameters/info from backends.

[visigoth]

Old business:

Lars Magne Ingebrigtsen <larsi@ifi.uio.no> writes:

> Why do you need to store that information in the group info?  Most
> other backends store information they need in separate files.  I
> realize that this may be a pain to do with IMAP, since that would make
> things much less portable, but can't you store that in a special
> folder on the IMAP server or something?  (I know nothing about IMAP,
> so just bonk me on the head if I'm raving here...)

Hmm.  I was just trying to find a conveniet place to shove it,
actually.  I was lazy and didn't want to go through the trouble of
making up some sort of separate file to store the info, though I
considered it.  The real problem is that this number that gets stored
is intimately related with the message numbers in the group file.
Without the base uid, message numbers are meaningless.  In any
case--why have two files when you can have one?

As far as putting stuff on the server--I can stow stuff away on the
ACAP server, and I'm considering doing so.  Problem with that for
right now is that the protocols for IMSP/ACAP are in great flux, and
there's no (ahem) server out there for ACAP yet.

I also just wanted something quick.

> The nntp backend just has `nntp-current-group' that says what the
> current group is.  The nnoo stuff will switch between various virtual
> servers for you, so that's no problem.

Yeah--I'm keeping track of stuff in a similar way.  Just trying to
keep all my bases covered.

> > The list appears to be down for now--but I look forward to input when
> > it comes back up. 
> 
> Has it been down?  Eeek!

Could have been some net problem on my side, too, but the machine the
MX record for ifi.uio.no points to wasn't responding to SMTP for some
days, nor was www.ifi.uio.no talking HTTP.  <shrug> But it's all
better now.

> You can call `gnus-group-set-parameter' directly, but that's somewhat
> naughty...

Let's see.  Right now I'm searching through the gnus-newsrc-alist to
find the group, and if I find it, I'm destructively modifying it to
include my information.  I threw this in (again out of laziness) to
avoid fetching the information multiple times--the first time I need
it, I put it into the group info.

I assume this way is even more naughty?

> That's what you're supposed to do -- the return value is just
> discarded.  The documentation here was *very* unclear; I've now fixed
> it. 

Okay.  Good to know.  :)  Thanks for updating the info.

New business:

It's well known that native methods and foreign methods are treated
differently, but I'm not sure I understood exactly how differently.
For some reason, if I set up nnimap as the native method, Gnus decides
that there are no messages in any group.  I'm not actually sure why.
By watching debugging output, I've noticed some things.  First, it
seems like getting the active list is the primary method Gnus uses to
get information about groups on a native server, whereas request-group
is used to get info from foregin groups.  I've also not been able to
figure out exactly when update-info is called for native groups, if at
all.

I'm having fun hacking on this, in any case.  I'm going to try to have
an alpha of nnimap.el available for ftp by Saturday, for anyone who's
interested.

John.