26 April 1999. Timur Kazimrov (timur@r1.sax.inkom.ru) 
    and Daniel Hellerstein (danielh@econ.ag.gov)

                                   PACKBACK

    An SRE-http pre-reply procedure that strips CRLFs, unused spaces, and comments
    from outgoing HTML documents, for selected clients. 

    This can be useful for large HTML documents in low bandwidth situations.

    You can also run it in stand-alone mode (possibly even under non-os/2 rexx)

A) Setup:
 1)  Copy this to your  GoServe\SRE "working directory"
 2)  Modify the user-changeable parameters (described below)

 2)  Edit the ClientsToPack. parameters 
 3) Modify the other user-changeable parameters -- pay special attention to  
    pieces_size and maxdocsize

 4) Idenfity PACKBACK as a Pre-Reply procedure (see PREREPLY.DOC for instructions on
    working with Pre-Reply procedures.

Notes:
  *  If you are using more then one pre-reply procedure, you'll have to create
     your own "pre-reply" manager that calls each pre-reply procedure in the
     proper sequence.


B) The User Changeable Parameters


ClientsToPack

    a) set ClientsToPack.0= # of entries
    b) set ClientsToPack.n= a numeric IP address (n=1,..,ClientsToPack.0).
       You can use * as wildcards.
       For example:   if the client's IP address is 199.122.33.1, then
       the following will match:
                ClientsToPack.3='199.122.33.1'
                ClientsToPack.3='199.122.*'
                ClientsToPack.3='199.12*'

    Example:
        CLIENTSTOPACK.0=1
        CLIENTSTOPACK.1='199.*' 


MaxDocSize:
   If the source document is larger than MAXDOCSIZE the compression
   won't be performed. This parameter should be tuned. Size is
   in bytes.
   Note: large files can take a minute or longer to process, which can cause
         an "inactive-timeout". To avoid this,  increase the options-limit-
         end_client_after_inactive GoServe parameter

  Example:
     MAXDOCSIZE=1500000  /* All documents larger that 1,500,000 bytes won't be compressed */


MinDocSize
   If the source document is smaller than MINDOCSIZE the compressing
   won't be performed. This parameter should be tuned. Size is
   in bytes. 

   Example:
       MINDOCSIZE=2000  /* All documents smaller that 2000 bytes won't be compressed */


Pieces_Size
   If size exceeds this limit (in bytes), and is less then maxdocsize, 
   then send  it 'in pieces'.
      This avoids inactive-timeout problems, but also means that
       transfer-encoding and encryption will NOT be attempted
   To disable, set pieces_size > maxdocsize /

   Example: 
        Pieces_Size=2000