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+ − 1 -------------------------------------------------------------------------------
+ − 2 NOFFLE Internals
+ − 3 -------------------------------------------------------------------------------
+ − 4
+ − 5 This document is, for the moment, a collection of jottings on aspects
+ − 6 of Noffle internals.One day it might make it into something resembling
+ − 7 documentation, but I wouldn't put your money on it. Use the Source,
+ − 8 Luke!
+ − 9
+ − 10 1. Where do things get stored?
+ − 11
+ − 12 Articles: Articles are held keyed by Message-ID in the articles
+ − 13 database, articles.gdbm. This is handled by database.[hc]. Articles
+ − 14 are marked with a status, indicating if they were only partially
+ − 15 downloaded (think overview mode) or if something went wrong on
+ − 16 retrieval.
+ − 17
+ − 18 Groups: The list of groups known is held in the groups database,
+ − 19 groupinfo.gdbm, keyed on group name. This holds the group first and
+ − 20 last article numbers, the last article number read on the remote
+ − 21 server, group creation and last access times, plus the group
+ − 22 description, the name of the server from which the group is drawn and
+ − 23 a flag indicating if posting to the group is allowed.
+ − 24
+ − 25 Local groups are indicated as belonging to a special server. They are
+ − 26 for the most part treated identically to remote groups (though the
+ − 27 whole business of auto-subscribe and auto-unsubscribe obviously
+ − 28 doesn't apply, and posting operates locally).
+ − 29
+ − 30 The fetchlist (fetchlist.[hc]) holds the list of group names Noffle
+ − 31 currently subscribes to, and the subscription mode.
+ − 32
+ − 33 Subscribed groups may have a file with their name in the overview
+ − 34 directory. This file - the overview file - contains details of the
+ − 35 articles in the group that can currently be read from the server. Each
+ − 36 entry in the file is an overview (over.[hc]), while a group overview
+ − 37 file is handled by content.[hc]. If no articles are left in a group,
+ − 38 the overview file is deleted.
+ − 39
+ − 40 The Noffle server loads the overview for a group into memory when it
+ − 41 needs to manipulate the group and uses its reckoning on the first and
+ − 42 last article number from there on. This may not correspond with the
+ − 43 first and last number given in the groups database entry. Typically,
+ − 44 the database first and last entries are updated from the overview on
+ − 45 completion of actions affecting the group.
+ − 46
+ − 47 Outbound articles are placed in a directory under the Noffle spool
+ − 48 'outgoing' directory. Each is in its own file, named by the article
+ − 49 Message-ID, in a directory with the name of the server. outgoing.[hc]
+ − 50 handle tracking what outbound messages are queued and queueing new ones.
+ − 51 When Noffle connects to the appropriate server, the message is posted
+ − 52 on and the file removed.
+ − 53
+ − 54 2. Posting
+ − 55
+ − 56 Posting to remote groups is straightforward; the article is placed in
+ − 57 the outgoing queue, and will be read back from the server as part of
+ − 58 collecting new messages for the group. The article is placed once only
+ − 59 in the queue, regardless of the number of external groups, as it only
+ − 60 needs to appear once on the remote server. Articles posted only to
+ − 61 newsgroups unknown to Noffle are rejected.
+ − 62
+ − 63 If the group is marked as 'can't post' ('n' in LIST ACTIVE) the post
+ − 64 is rejected immediately. Note you can't have moderated local groups at
+ − 65 the moment; you can have read-only ones, though.
+ − 66
+ − 67 Control message are similarly passed on, unless the control is
+ − 68 'cancel' and the cancel can be done entirely locally because the
+ − 69 article is still in the outgoing queue.
+ − 70
+ − 71 Posts to local groups appear in the article database
+ − 72 immediately. Control messages (control.[hc]) for local groups are
+ − 73 honoured, though currently only 'cancel' does anything.
+ − 74
+ − 75 Things get more complex when an article is cross-posted to a local and
+ − 76 remote group. Essentially, both the above happen; if the remote server
+ − 77 does not change the Message-ID, the local copy will be the definitive
+ − 78 for both groups. Obviously if the remote server does change the
+ − 79 Message-ID, Noffle will tread the article coming back from the server
+ − 80 as a new one.
+ − 81
+ − 82 post.[hc] holds the code for posting local articles.
+ − 83
+ − 84 The posting code in post 1.0 Noffle should (i.e. I'll do it if time
+ − 85 permits) be rearranged to provide one function to post (or reject) an
+ − 86 article regardless of original source. This would hopefully make it
+ − 87 clearer what happens during a post, and make it easy to add a
+ − 88 command-line article post function, which could remove the necessity
+ − 89 for Python or Perl intervention gateing mailing lists into local newsgroups.
+ − 90
+ − 91 3. Pseudo articles
+ − 92
+ − 93 Noffle generates various pseudo articles itself (see pseudo.[hc]), to
+ − 94 inform the user of changes of state or to give instruction. All but
+ − 95 one are, in fact, done by generating and posting a regular article,
+ − 96 but one is special; the general information article.
+ − 97
+ − 98 The gen info article is the one shown when one tries to read from a
+ − 99 currently unsubscribed (Noffle is not subscribed to it, that it)
+ − 100 newsgroup. It is apparently present in every single group known to
+ − 101 Noffle, but is faked; it never appears in the article database. LIST
+ − 102 ACTIVE fakes the first and last article numbers for a group if it
+ − 103 knows the group is not subscribed to (and not local), and entry to a
+ − 104 group with the GROUP command will cause an overview to be added to the
+ − 105 group overview in memory only. If the article is not read, the
+ − 106 overview is lost unsaved when moving to the next group.
+ − 107
+ − 108 Reading the article triggers stuff happening. If auto-subscribe is on,
+ − 109 a pseudo article confirming subcription is posted and the group
+ − 110 overview saved. Gen info articles are not normally saved in overviews,
+ − 111 but to prevent them vanishing very suddenly their overview is saved
+ − 112 with other articles in the group if they form part of the sequence of
+ − 113 the group. In this case it will persist until the subscription confirm
+ − 114 article expires. This will not stop another gen info being generated
+ − 115 if (say) the group gets auto-unsubscribed.
