On Mon, 17 Jan 2011, Curt, WE7U wrote:
Gerry probably needs to tell us how to retrieve and reduce the data to what
we need, then we can code up a script or program to send APRS representations
of it and then run that from multiple sites for redundancy, feeding into
Firenet or another server Gerry sets up. Let's give him a day or so to
'splain.
I have a modularized Perl script that can authenticate to a server and
throttle the objects being sent to whatever rate you wish. This prevents
overloading servers with a big burst of packets. It would need a module
written to snag the data and create APRS packets, then the parent Perl script
takes care of delivering them. I'd rather this script not get out in the
wild, but for a small group of trusted people running a needed service, it's
a quick start. Someone could certainly create a program in another language
that does similar things later if needed.
FWIW: I have under testing a Perl script which takes a live NWS feed and
reduces it to APRS WX Alert strings.
I then feed that to another script which sends the alert several different places,
including Lynn's e-mail, my 2nd Xastir instance here which isn't connected to RF or INET,
and directly to RF using the Linux "beacon" command.
The initial portion of the test lash-up is laughable, but gets the packets
where I needed them for development:
Remote server w/weather feed, regex to snag the alerts of interest and send
them to e-mail.
Procmail them off to GMail.
Snag them from GMail to my home machine with fetchmail.
Procmail them through the Perl scripts.
Later I plan to send them from the remote server directly into some
APRS-IS-like server, so they won't be going through my home system at all and
won't have the inherent e-mail delays. My home Xastir igate can connect to the
weather alert server and have some of the local NWS offices listed in the
nws-stations.txt file so that I can gate them to local RF. Others will be able
to do the same for their areas.
While doing some of the earlier testing I leaked some of the alerts to Firenet
accidentally (xastir_udp_client into my Xastir igate ends up sending them to
the internet server too!). Firenet promptly relayed them to APRS-IS since they
are just APRS messages. Lesson learned.
During testing this weekend with 3rd-party packets going to local RF I
discovered that some igates leak alerts back to APRS-IS under some conditions.
In fact I haven't figured out yet how to make UI-View stop doing so, but I
haven't given up yet either!
So... Just letting everyone know that we are close, but the original idea of
gating them to Firenet may be unworkable. We may need to set up a separate
weather alert server if we want to keep them off APRS-IS.
Notes: The sequence bytes are most likely computed differently than Dale's or
Pete's weather servers, and there is no finger server capability or multi-line
object capability at this time. I plan to work on the multi-line objects but
may not do the finger server due to security considerations. Maybe we can set
up to snag the full alert text from weather.gov via http instead...
--
Curt, WE7U. <http://www.eskimo.com/~archer>
APRS: Where it's at! <http://www.xastir.org>
Lotto: A tax on people who are bad at math. - unknown
Windows: Microsoft's tax on computer illiterates. - WE7U.
The world DOES revolve around me: I picked the coordinate system!"
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