DBUS – Linux Desktop Hacking - Mid-Hudson Valley Linux Users ...

Sean Dague
DBUS – Linux Desktop Hacking
With Ruby Examples
MHVLUG Meeting
Feb 6 th 2008
Sean Dague
sean * dague * net
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Sean Dague
Returning to the Desktop...
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Sean Dague
What is DBUS?
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Sean Dague
GDBUS
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Sean Dague
Ruby Quick Introduction
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Sean Dague
“I wanted a scripting language that was more powerful than Perl,
and more object-oriented than Python.”
#!/usr/bin/ruby
puts “Hello World”
-Yukihiro “matz” Matsumoto (Ruby Creator)
def repeat
5.times do
puts “Try not to repeat yourself”
end
end
repeat
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Sean Dague
Ruby Language Features
● Lots of ideas borrowed from Perl (regex is first class
language contruct)
● Got rid of the semi-colon like Python, but didn't make
white space important
● Everything is an object
● Lisp inspired “do block”
● Mixins
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Sean Dague
Ruby Gymnastics
@strips = @user.
comics.
collect {|c|
c.strips.find(:all, :conditions => [”date > ?“, 7.days.ago])
}.
flatten.
delete_if {|c| c == nil}.
sort_by {|c| c.date}
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Sean Dague
Learning more on Ruby
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Sean Dague
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Sean Dague
#!/usr/bin/ruby
# From the ruby-dbus project
require “dbus”
Getting on the Bus
# System Bus is for OS events, shared for all users
system_bus = DBUS::SystemBus.instance
# Session Bus is per desktop instance
session_bus = DBus::SessionBus.instance
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Sean Dague
Connecting to Pidgin
def connect_pidgin(session_bus)
# Get the pidgin service
pidgin_dbus = session_bus.service("im.pidgin.purple.PurpleService")
# Get the object from this service
pidgin = pidgin_dbus.object("/im/pidgin/purple/PurpleObject")
# Introspect it
pidgin.introspect
if pidgin.has_iface? "im.pidgin.purple.PurpleInterface"
pidgin.default_iface = "im.pidgin.purple.PurpleInterface"
puts "We have Pidgin interface"
end
return pidgin
end
pidgin = connect_pidgin(session_bus)
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Sean Dague
Talking to Pidgin
def recycle_pidgin(pidgin)
accounts = pidgin.PurpleAccountsGetAll
for account in accounts[0]
if pidgin.PurpleAccountIsConnected(account)[0] > 0
pidgin.PurpleAccountDisconnect(account)
end
pidgin.PurpleAccountConnect(account)
end
end
def set_status(pidgin, type, name, message)
status = pidgin.PurpleSavedstatusFind(name)[0]
if not status > 0
status = pidgin.PurpleSavedstatusNew(name, type)[0]
end
pidgin.PurpleSavedstatusSetMessage(status, message)
pidgin.PurpleSavedstatusActivate(status)
end
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Sean Dague
Listening for Events
pidgin.on_signal("SentImMsg") { set_active(pidgin) }
screensaver.on_signal("ActiveChanged") {|s|
if s
mute
set_away(pidgin)
else
unmute
end
}
main = DBus::Main.new
main

Sean Dague
Without Introspection
def connect_netman(bus)
n_dbus = bus.service("org.freedesktop.NetworkManager")
netman = n_dbus.object("/org/freedesktop/NetworkManager")
poi = DBus::ProxyObjectInterface.new(netman,
"org.freedesktop.NetworkManager")
return poi
end
netman = connect_netman(system_bus)
netman.on_signal(system_bus, "DeviceNowActive") { |device, network|
pp device # "/org/freedesktop/NetworkManager/Devices/wlan0"
pp network # “szj”
recycle_pidgin(pidgin)
}
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Sean Dague
Possibilities Galore
● Make Pidgin Idle Aware based on other device activity
● Connect Pidgin to Twitter for Status
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Sean Dague
MHVLUG Upcoming
● Join the mailing list - http://mhvlug.org
● Come join us at Ruby Tuesday's – 8pm
● MHVLUG Turns 5 next Month
● Upcoming Meetings
– March - ?
– April – Configuring your kernel
– May – Small Office Linux
● Hopefully back to regular venue next Month
– Thanks to Porkchop and Greg for finding alternate venues for the
past 2 months
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