Post-Receive using a Worker Box FS

To do a lengthy operation after receiving a fax, we strongly recommend creating a separate worker-box FS file to perform the operation.  This is because the calling party will have already dropped the call before the post-receive operation is started, allowing a further call to be offered, but the CopiaFacts line thread will still be busy on the post-receive operation.

This is especially important for systems which have a small number of inbound lines, as well as for systems of any size which have a high volume of inbound calls.

Initiating the post-receive operation

The post-receive operation is initiated in the normal way, by means of a $post_receive command in the MBX file, of type infobox or infoboxall.  Instead of starting an infobox sequence to perform the lengthy operation, it will instead transfer to a simple infobox which creates a worker-box FS file.  The MBX file should therefore contain for example:

$post_receive PRWORKER infobox

Use the keyword infoboxall to call the post-receive operation for failed receive operations as well as successful receive operations.

The post-receive infobox

The post-receive infobox may need to transfer variables pertaining to the received fax into the worker-box FS file.  These variables are of three types:

user variables set by $set_var statements in the post-receive infobox

system variables such as DNIS and ANI which refer to the received call

PR_... variables which refer to the received fax.

The first two types are copied by specifying the $var_def_copy command with no parameters.  The third type is copied by specifying the same command with parameter PR.

The post-receive infobox should therefore normally contain just the following commands (FS commands in red):

; PRWORKER.IIF post-receive using worker box

$type FSFILE

$var_def_copy          ; copy system variables

$var_def_copy PR       ; copy PR_... variables

$worker_box PRLENGTHY  ; post-receive taking time to process

$fax_user   @FFUSER\FAX.USR


Note that omitting the $fax_user command from the FS file will cause an FS command to be automatically generated referencing the USR file which controlled the inbound call.

The worker-box infobox

In the worker-box infobox you need to perform the operation which might have taken too long to complete if performed at post-receive time.  The variables you have specified to be copied will be defined on FS-file $var_def commands and will be available for use.  For example you might wish to convert the received TIF file to a PDF file, as follows:

; PRLENGTHY.IIF worker box to convert file

$type decision

$set_var RES "$fn:convertfile(@PR_FAXPATH,@PR_FAXPDF)"

$if @RES < 0 

  $next_box PRERROR


  $next_box s:KILL_MAINT_OP


Note that for simple fax-to-email applications it is not necessary to convert to PDF explicitly, because this can be achieved by specifying a pdf content-type on $email_attach.