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Linux Magazine: Perl of Wisdom: Moving Your News Service

[ Thanks to Robert
McMillan
for this link. ]

“Several months ago in this space, I talked about how my ISP was
looking at the performance of their news server. I wrote a program
to see just how bad the news service was compared to the other
local ISPs, using Deja as a baseline. Well, the ISP just got bought
out by a big national chain. They decided not to fight the spotty
news service any more and just convert over to the conglomerate’s
big service. The problem with moving from one news server to
another is that the article numbers are not in sync, so a .newsrc
file will have the right newsgroups but the wrong “read” marks. And
since I read a lot of newsgroups, I don’t have time to reread
existing articles, and I don’t want to just throw away any new
articles.”

The solution is a bit complicated and requires extensive
bookkeeping, but that’s what computers are for, and Perl in
particular.
What you need to do is mark as read any articles
you’ve already seen. Messages are uniquely identified by a message
ID, and you can get that mapped into article numbers via the
appropriate XHDR request to the NNTP server.”

“So, basically, for every subscribed newsgroup, we fetch the
message IDs of the last 500 articles from the new server (500 being
the maximum number of unread articles per group I’d care to face).
Then, we fetch the last 1,500 or so message IDs from the old
server. Then, for every message ID on the new server, if I’ve
already read it on the old server, mark it as read in the new
newsrc.”

Complete
Story