s-o-1036 June 1994

8.2. Encoded Batches

When transmitting news, especially over communications links
that are slow or are billed by the bit, it is  often  desir-
able  to  batch  news  and  apply  data  compression  to the
batches.   Transmission  links  sending  compressed  batches
SHOULD use out-of-band means of communication to specify the
compression algorithm being used.  If there  is  no  way  to
send out-of-band information along with a batch, the follow-
ing encapsulation for a compressed batch MAY be used:

     ec-batch             = "#! " compression-keyword eol compressed-batch
     compression-keyword  = "cunbatch"

A line containing a keyword indicating the type of  compres-
sion  is  followed  by the compressed batch.  The only truly
widespread compression keyword  at  present  is  "cunbatch",
indicating  compression  using  the widely-distributed "com-
press" program.  Other compression keywords MAY be  used  by
mutual agreement between the hosts involved.

INTERNET DRAFT to be        NEWS                    sec. 8.2


     NOTE:  An encapsulated compressed batch is NOT, in
     general, a text file, despite  having  an  initial
     text  line.  This combination of text and non-text
     data is often  awkward  to  handle;  for  example,
     standard  decompression  programs  cannot  be used
     without first stripping off the initial line,  and
     that  in  turn is painful to do because many text-
     handling tools that are  superficially  suited  to
     the  job  do  not  cope  well  with non-text data.
     Hence the recommendation that out-of-band communi-
     cation be used instead when possible.

     NOTE: For UUCP transmission, where a batch is typ-
     ically transmitted by invoking the remote  command
     "rnews"  with  the  batch  as  its input stream, a
     plausible out-of-band method for indicating a com-
     pression  type would be to give a compression key-
     word in an option to "rnews", perhaps in the form:

          rnews -d decompressor

     where  "decompressor"  is the name of a decompres-
     sion program (e.g. "uncompress" for a  batch  com-
     pressed  with  "compress"  or "gunzip" for a batch
     compressed with "gzip").  How  this  decompression
     program  is  located  and invoked by the receiving
     relayer is implementation-specific.

     NOTE: See the notes in section 8.1 on the inadvis-
     ability  of  feeding  batches  directly to command
     interpreters.

     NOTE: There is exactly one blank between "#!"  and
     the  compression  keyword, and the EOL immediately
     follows the keyword.