Control Hubs: Bringing It All Together - Smart Home Automation with Linux and Raspberry Pi - page 254

And amend the web configuration, as shown earlier. The moonbeam user is consequently granted read-only
permission to the database for security, while the real user (e.g. steev) is able to add, change, and remove bookmarks
through the database as normal.
The weather applet simply reads the precached forecasts (made earlier in the day by the Minerva user's crontab )
stored in /var/log/minerva/cache/weather.txt and /var/log/minerva/cache/weather_info.txt to look for
matching strings that determine which icon will be drawn on the page.
There is also a currency calculator, based on the http://xurrency.com web service that you saw in Chapter 6.
Its inclusion is primarily educational.
Another applet that merely wraps an existing Bearskin command consists of live departure boards. It calls
$MINBASE/bin/ldbquery to determine the next trains from your predetermined stations. There is no configuration
here, since the ldbquery script accepts arguments designated as the source and destination stations on your journey
from hard-coded values in the applet.
And finally, the RSS news applet makes use of the news-read command to render the most recent news stories
into your browser. Each news feed is governed by the unique pairing of a site ID and username, which presents a file
stored in $MINBASE/etc/users/public/news/slashdot , for example, that holds the site name and URL for the
RSS feed:

Slashdot
http://rss.slashdot.org/Slashdot/slashdot

This news is downloaded on demand, either explicitly with news-get public slashdot or implicitly when a story
is read with news-read slashdot public text 0 headline . At this point, the RSS content is downloaded and stored
in a local cache where the various elements can be read. The system is smart enough to not redownload content if it is
fairly fresh and can render the output in text, HTML, or vocal-friendly text. The latter case removes any markup. The
WARP applet displays the elements, headline, URL, and story, individually, using the news-read arguments shown
earlier. The same approach can be used on the command line, allowing the alarm clock to include a line such as the
following to give you the headlines in the morning:

$MINBASE/bin/say default (`news-read slashdot public vox 0 headline´)

Administration
These are all very simple applets to quickly review the status logs, processes, and server, without you having to log in
through SSH. You will need to have authority to use these tools, so give yourself permission with the following:

minuser auth [myusername] system set rw

The typical applets available here report the following:

u Free disk space (the specific devices can be specified in

warp/conf/diskfree/diskfree.conf )

u User agent of the browser (for debugging mainly)

u Samba status

u Processor top

u UPS status

u Various log files

u Bluetooth scanner results