CrossSpider is web frontend for DX cluster software. Some DX clusters used Java applet client. But this technology is little obsolete yet. So I wrote this small frontend for OK0DXI. The name CrossSpider links to DX Spider which is used here.
- CrossSpider can be used only for read-only access to DX cluster. It does not handle user connection. It is connected as special user which have no filters set.
- Band filtering is done on client so all spots are transferred via network.
How it works
On the DX cluster computer, small Perl daemon "robot.pl" is running. It is connected to DX cluster using telnet (exactly using netcat program). I start it using systemd but in older distros I used traditional nohup robot.pl & in /etc/rc.local.
The daemon inserts all spots and other messages to PostgreSQL database.
Next part is web page which uses HTML5/Ajax to access latest spots from PostgreSQL.
First set up the PostgreSQL database. In this text database name is crossspider, user is robot:
# su - postgres $ createdb crossspider $ psql crossspider crossspider=# create table lines(id serial, stamp timestamp with time zone, call text, qrg numeric(10,1), spot text); crossspider=# create user robot with password '01001' crossspider=# grant all on lines TO robot; crossspider=# grant all on lines_id_seq TO robot;
Allow access for user robot. Edit /etc/postgres/*/pg_hba.conf and add this line:
# TYPE DATABASE USER ADDRESS METHOD localhost crossspider robot password
Robot is reference to PE1NWL's DX robot.
Of course you have to install Perl first. But it is probaly already part of your distribution. Copy robot.pl somewhere (/usr/local/sbin).
If you use current linux distribution, you probably use systemd for service maintain. It's config directory is /etc/systemd/system. Here create file named robot.service:
[Unit] Description=DX-robot daemon Requires=spider.service # depends on how you start the DX spider After=network.target spider.service [Service] Type=simple User=nobody StandardOutput=journal StandardError=journal Restart=always RestartSec=3 ExecStart=/usr/bin/perl /usr/local/sbin/robot.pl RestartSec=10 Restart=on-failure [Install] WantedBy=multi-user.target
If you use older distro, you can use traditional /etc/rc.local or something:
# /etc/rc.local nohup /usr/bin/perl /usr/local/sbin/robot.pl &
Edit the robot.pl file and modify head part to set access to database and DX cluster. Of course you have to enable access also on your DX Cluster software.
Copy ajax.php and index.php to root if your website. Edit first part of ajax.php and set up access to database.