From: Ricardo Jasinski <rjasinski@...>
Date: 2007-07-15T21:15:03+09:00
Subject: Re: Real project -- general application structure

Hi Florian,

this is starting to look good. I'd better ellaborate on the
application a little bit more:

The remote units will monitor a series of environmental variables on
the ambient where they are installed. Whenever there's a significant
change, or periodically, the units will open a socket to the server
and send it some updated data.

This is the remoute units <-> server half of our application; in
addition to that, we need to put up a web server so that the person
who installed the remote units on his locations can easily see the
updated status of all sites. Basically, that's it.

This was my first idea for the application structure:


        TCP/IP sockets
                      +---------------------+           +------------+
[Sensor#1] <------->  |                     |           |            |
[Sensor#2] <------->  | Sensors interfacing | <-------> | Web server |
[Sensor#3] <------->  |      application    |           |   (App#2)  |
    ...               |        (App#1)      |           +------------+
                      +---------------------+             ^
                                           ^             /
                                            \  ________ v
                                             v/        \
                                              \________/
                                              |        |
                                              |   DB   |
                                              \________/


App#1 needs to access the DB mainly for validation purposes. App#2
needs DB access to provide nicely formatted web pages with sensor data
and other stuff to the guy on the couch who will be checking out the
sensors status on his web browser.

Ah, and I can't install any software on the guy's PC.

Regarding the sensors, they are somewhat limited embedded devices, so
I can count on them having a decent TCP/IP stack, but I don't think I
could squeeze anything like RPC or XML into them.

> Instead I'd embed, if you really need so, a java applet that accepts
> messages from your event machine telling it to refresh or even the new
> information.

This sounds nice, does it fit the above description?

Thanks again!

Mfg,

Ricardo.