Bommanews technical

BommaNews Internals

Internal facts in more detail:

Directory structure:

In the program directory, a few subdirectories are created: one of them is called "Download", this is the initial place where files are downloaded (funny, huh ;-)
Besides download, there are one or more directories with the same names as the newsservers you use: the information about groups and articles is stored here.

Files

All data files use a binary format as described below.
groups.dat: newsgroup information, 1 file per server ("*" = no longer used, but must be present)

GROUPS.DAT
# bytes		Data
2 bytes		Length server name
? bytes		Server name (*)
2 bytes		Length last newsgroup mask
? bytes		Last used newsgroup mask (*)
8 bytes		Date and time group names last collected
4 bytes		Number of newsgroups that follows
Per group	2 bytes	Length group name
	? bytes	Group name
	8 bytes	Time of last update
	4 bytes	Index number (server) oldest existing message in group
	4 bytes	Index number (server) most recent message in group
	2 bytes	Flag (0 / FFFF): server allows posting.

*.bpg: header information, 1 file per newsgroup.

*.BPG
# Bytes			Data
4			Number of postings (1 posting can be more than 1 header, but is shown in the message list as a single entry)
Per shown header	4		Number of messages in this posting (found)
	4		Number of messages in this posting (indicated in message headers)
	4		Total number of lines in all messages of this posting
	4		Totaal number of bytes in all messages of this posting (as indicated by server)
	4		Number of individual headers in this posting (should be identical to the number of found messages, = the number of "subheaders" following below)
	2		Length of identification key
	?		Identification key for this posting. For "alien" posts this is the subject, minus (nn/mm) message counter at the end if there is any. For bommanews-posts: the unique identification code that all messages belonging to the same file have in the Message-ID header (see below), followed by the start of the subject header.
	2		Length of shown subject line
	?		Subject line as shown in the message list. For "alien" posts this is the same as the key.
	Per individual message	4	Index number of individual message on server
		2	Sequence number of this message in posting ('nn' of the 'nn/mm' counter).
		4	Number of text lines in this message (as indicated by server)
		4	Size in bytes of this message (as indicated by server)
		8	Date & time of posting (binary date format)
		2	Length of From header
		?	From header
		2	Length of "Message-ID" header
		?	Message-ID header
		2	Length of "References" header
		?	References header
		2	Length of "Subject" header
		?	Subject header
		2	Length of "XRef" header
		?	XRef header.

Message headers

The Message-ID header composition below must strictly be followed by other versions of B-News written for other platforms, to ensure correct recognition of postings by all versions.
- Start with <bpst
- Next a code for date and time of posting of the individual message, in the format: yymmddhhnnssddd
- The date/time code is followed by a period (".")
- Next a series of 10 arbitrarily picked capitals (such as DXHJWHUINW). This code has to be identical for all messages that are part of the same file (the only difference in the message-ID's within a file is the time code).
- Next an "@" sign
- Finally the computer name, and a terminating ">". The computer name is initially retrieved from the system's network settings, but can be overridden in the configuration window.
As a whole, a Message-ID header could look like this example:
Message-ID: <bpst010106235119538.DXHJWHUINW@hyperion>
Three MIME headers are present:
- MIME-Version: 1.0
- Content-Type: Application/Octet-Stream;file="filename.ext.bn"
  The filename is only appended starting with version 1.0.6. "filename.ext" is the original full filename.
- Content-Transfer-Encoding: X-Bommanews-224-ZZZ
  ZZZ represents the encoding block size, which was settable in versions 0.x.x. Currently the value is fixed at 40.
  '224' indicates that 224 different character values are used (0x20 - 0xFF): this leaves open some room for adaptation if situationes arise where not all values are handled correctly.
In the Subject header the user's description is followed by "-:-", the file name, and a sequence number of the message in the posting.
Newsgroups: bommanews does not support nor condone crossposts.
Distribution: local is the default setting, an option to override this is included.
X-No-Archive: yes is the default, and can also be overridden.
A Followup-to header has not been implemented in BommaNews yet, but may be added in a leter version.