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How FSC Messages Leave HP Desk
To send messages from HP Desk to an external application an address
(mailnode) must be configured for the application and it must be routed
through an FSC gateway. Messages for the application are sent to this
address.
These messages are queued at the gateway in a queue for the address they
are being sent to (mailnode queue). When the gateway is opened, messages
held on the queue pass through the gateway and are stored as MPE files.
The gateway is opened at configured times. (See HP DeskManager
Administration for more information.)
Each MPE file is given a unique name which consists of the letter E
followed by the date and time at which the file is created. These "E
files" are also known as "nodefiles". This name is written to a record
in the IPC file for that gateway. Each gateway needs an IPC file, which
must be built before you can use FSC. The MPE files are usually held in
the group HPMAIL.HPOFFICE but other groups within HPOFFICE may be
specified in the EFT/FSC configuration menu of Mailconfig.
The messages are now ready to be processed by the application. Any
application program you write to pick up messages from HP Desk will have
to be able to identify the MPE files containing the messages.
In addition an application which communicates with a foreign mailing
system must:
* Translate the MPE files to a format acceptable to the foreign
system, if necessary.
* Open communication with the foreign system and transmit the files.
It is possible to write an application program to take messages from more
than one gateway. However, it is not possible to have more than one
application sharing a single gateway.
How the Gateway Moves Messages out of HP Desk
The following elements are involved in transporting outgoing messages
from the gateway:
![[]](../../pic3k/M011771/FFN43c50.gif)
Here is the sequence of events:
1. The Gateway IPC file is opened by the Master Truck. This file
name is configurable.
2. The Master Truck takes messages from one mailnode queue in the HP
Desk database, translates them to the format appropriate to the
gateway and writes them to a temporary MPE file. The file
consists of a special ARPA header followed by the actual message.
This process continues until the file is full or there are no
messages left on the node queue.
3. The MPE file is closed and made permanent with a unique name. The
date and time of creation is used to name the file in the format
Ejjhhmmt, where:
jj is the Julian day of the year modulo 100
hh is the hour number
mm is the minute number.
t is the number of the Master Truck that took the message.
These files are referred to generically as E files. Therefore an
E file sent on the 256th day of the year, at 08:54, by Master
Truck0 would be named E5608540.HPMAIL.HPOFFICE.
4. The Master Truck writes the name of the MPE file to the IPC file
and closes the IPC file. It then goes on to process more messages
on the same node queue, or messages for other nodes routed through
the gateway.
5. The external application program can try to read the IPC file
continuously, at specified times, or when run by the Operator.
Once the Master Truck has written the name of the MPE file to the
IPC file, the external application program can read the IPC file.
6. After reading the MPE filename from the IPC file and so destroying
the IPC file record (reading an IPC file is a destructive read),
the external application program reads the file containing the
messages and processes it.
7. If necessary, the external application program converts the MPE
files into a format acceptable to the receiving system.
8. The external application program attempts a further read of the
IPC file and repeats steps 6 to 8 each time the read is satisfied.
NOTE Private messages cannot go through an FSC gateway unless you
specify that this is allowed in the EFT/FSC Menu of Mailconfig.
See HP DeskManager Administration more information.