News batches follow a particular format that is the same for
B News, C News, and INN. Each article is preceded by a line like this:
count is the number of bytes in the article. When
you use batch compression, the resulting file is compressed as a whole and
preceded by another line, indicated by the message to be used for unpacking.
The standard compression tool is
compress, which is marked by:
Sometimes, when the news server sends batches via mail software that
removes the eighth bit from all data, a compressed batch may be
protected using what is called c7-encoding; these
batches will be marked by c7unbatch.
When a batch is fed to rnews on the remote site, it
checks for these markers and processes the batch appropriately. Some
sites also use other compression tools, like gzip,
and precede their gzipped files with the word
zunbatch instead. C News does not recognize
nonstandard headers like these; you have to modify the source to
support them.
In C News, article batching is performed by
/usr/lib/news/batch/sendbatches,
which takes a list of articles from the site/togo file
and puts them into several newsbatches. It should be executed once per hour,
or even more frequently, depending on the volume of traffic. Its operation
is controlled by the batchparms file in
/var/lib/news. This file describes the maximum batch
size allowed for each site, the batching and optional compression program
to be used, and the transport for delivering it to the remote site. You
may specify batching parameters on a per-site basis, as well as a set of
default parameters for sites not explicitly mentioned.
When installing C News, you will most likely find a
batchparms file in your distribution that contains
a reasonable default entry, so there's a good chance that you won't have
to touch the file. Just in case, we describe its format. Each line consists
of six fields, separated by spaces or tabs:
site size max batcher muncher transport |
- site
site is the name of the site to which the entry
applies. The togo file for this site must reside in
out.going /togo below the news spool. A site name of
/default/ denotes the default entry and
is to match any site not directly specified with an entry unique to it.
- size
size is the maximum size of article batches
created (before compression). For single articles larger than this, C News
makes an exception and puts each in a single batch by itself.
- max
max is the maximum number of batches created and
scheduled for transfer before batching stalls for this particular site. This
is useful in case the remote site should be down for a long time,
because it prevents C News from cluttering your UUCP spool directories
with zillions of newsbatches.
C News determines the number of queued batches using the
queuelen script in /usr/lib/news/.
If you've installed C News in a prepackaged format, the script should not
need any editing, but if you choose to use a different flavor of spool
directories, for example, Taylor UUCP, you might have to write your
own. If you don't care about the number of spool files (because you're the only
person using your computer and you don't write articles by the megabyte),
you may replace the script's contents by a simple exit 0
statement.
- batcher
The batcher field contains the command used for
producing a batch from the list of articles in the togo
file. For regular feeds, this is usually batcher. For
other purposes, alternative batchers may be provided. For instance, the
ihave/sendme protocol requires the article list to be turned into
ihave or sendme control messages,
which are posted to the newsgroup
to.site. This is performed by
batchih and batchsm.
- muncher
The muncher field specifies the compression
command. Usually, this is compcun, a script that produces a
compressed batch.[1]
Alternatively, suppose you create a muncher that uses
gzip, say gzipcun (note that you
have to write it yourself ). You have to make sure that
uncompress on the remote site is patched to
recognize files compressed with gzip.
If the remote site does not have an uncompress command,
you may specify nocomp, which does not do any compression.
- transport
The last field, transport, describes the
transport to be used. A number of standard commands for different
transports are available; their names begin with
via. sendbatches passes them
the destination sitename on the command line. If the
batchparms entry is not /default/, sendbatches
derives the sitename from the site field by
stripping it of anything after and including the first dot or
slash. If the batchparms entry
is /default/, the directory
names in out.going are used.
To perform batching for a specific site, use the following command:
# su news -c "/usr/lib/news/batch/sendbatches site" |
When invoked without arguments, sendbatches handles all
batch queues. The interpretation of “all” depends on the presence
of a default entry in batchparms. If one is found, all
directories in /var/spool/news/out.going are checked;
otherwise, sendbatches cycles through all entries in
batchparms, processing just the sites found there.
Note that sendbatches, when scanning the
out.going directory, takes only those directories
that contain no dots or at signs (@)
as sitenames.
There are two commands that use uux to execute
rnews on the remote system:
viauux and viauuxz. The latter
sets the –z flag for uux to
keep older versions from returning success messages for each article
delivered. Another command, viamail, sends article
batches to the user rnews on
the remote system via mail. Of course, this requires that the remote
system somehow feeds all mail for rnews to its local news system. For a
complete list of these transports, refer to the
newsbatch manual page.
All commands from the last three fields must be located in either
out.going/site or
/usr/lib/news/batch. Most of them are scripts; you
can easily tailor new tools for your personal needs. They are
invoked through pipes. The list of articles is fed to the batcher on standard
input, which produces the batch on standard output. This is piped into the
muncher, and so on.
Here is a sample file:
# batchparms file for the brewery
# site | size |max |batcher |muncher |transport
#-------------+--------+-------+---------+-----------+-----------
/default/ 100000 22 batcher compcun viauux
swim 10000 10 batcher nocomp viauux |
