firefox not opening - cron, ruby, firewatir - ruby

Question

I have written a ruby script which opens up dlink admin page in firefox and does a ADSL connection or disconnection.
I could run this script in the terminal without any problem. But if I put it as cron job, it doesn't fire up firefox.
This is the entry I have in crontab
# connect to dataone
55 17 * * * ruby /home/raguanu/Dropbox/nettie.rb >> /tmp/cron_test
I see the following entries in /tmp/cron_test. So it looks like the script indeed ran.
PROFILE:
i486-linux
/usr/bin/firefox -jssh
But I couldn't figure out why I didn't see firefox opening up, for this automation to work. Here is /home/raguanu/Dropbox/nettie.rb
#!/usr/bin/ruby -w
require 'rubygems'
require 'firewatir'
require 'optiflag'
module Options extend OptiFlagSet
character_flag :d do
long_form 'disconnect'
description 'Mention this flag if you want to disconnect dataone'
end
flag :l do
optional
long_form 'admin_link'
default 'http://192.168.1.1'
description 'Dlink web administration link. Defaults to http://192.168.1.1'
end
flag :u do
optional
long_form 'user'
default 'admin'
description 'Dlink administrator user name. Defaults to "admin"'
end
flag :p do
optional
long_form 'password'
default 'admin'
description 'Dlink administrator password. Defaults to "admin"'
end
flag :c do
optional
long_form 'connection_name'
default 'bsnl'
description 'Dataone connection name. Defaults to "bsnl"'
end
extended_help_flag :h do
long_form 'help'
end
and_process!
end
class DlinkAdmin
include FireWatir
def initialize(admin_link = "http://192.168.1.1", user = 'admin', pwd = 'admin')
#admin_link, #user, #pwd = admin_link, user, pwd
end
def connect( connection_name = 'bsnl' )
goto_connection_page connection_name
# disconnect prior to connection
#browser.button(:value, 'Disconnect').click
# connect
#browser.button(:value, 'Connect').click
# done!
#browser.close
end
def disconnect( connection_name = 'bsnl' )
goto_connection_page connection_name
# disconnect
#browser.button(:value, 'Disconnect').click
# done!
#browser.close
end
private
def goto_connection_page( connection_name = 'bsnl')
#browser ||= Firefox.new
#browser.goto(#admin_link)
# login
#browser.text_field(:name, 'uiViewUserName').set(#user)
#browser.text_field(:name, 'uiViewPassword').set(#pwd)
#browser.button(:value,'Log In').click
# setup > dataone
#browser.image(:alt, 'Setup').click
#browser.link(:text, connection_name).click
end
end
admin = DlinkAdmin.new(Options.flags.l, Options.flags.u, Options.flags.p)
unless Options.flags.d?
admin.connect( Options.flags.c )
else
admin.disconnect( Options.flags.c )
end
Any help is appreciated.

Answer 1

You need to have a DISPLAY environment pointing at a valid X-server. This could either involve setting it to the value ":0.0" (without quotes), such that it refers to your local standard DISPLAY.
There's a few things to keep in mind though:
You could run an X virtual frame buffer (xvfb), so that Firefox simply uses that as it's display. This would mean that Firefox would be able to do all its graphical operations, but that it would be independent of your standard graphical environment. You'll have to set the DISPLAY variable appropriately so that it points to the xvfb instance. For instance, if you invoke xvfb as follows:
Xvfb :1 -screen 0 1600x1200x32
Then you'll be able to use this by setting the DISPLAY variable to :1
You're starting a full-blown firefox instance to simply connect or disconnect your modem. You would most likely be able to use "curl" to send the appropriate HTTP requests to the server, such that it performs a connect or disconnect for you. One way to trivially see what you should recreate would be to install a Firefox plugin such as LiveHTTPHeaders and note down the most important HTTP requests as you perform the actions manually.
There's even a ruby binding for curl:
libcurl for Ruby. The resulting script should be much smaller than your current script.

Answer 2

Programs run from cron don't have your interactive environment. Therefore they don't have and DISPLAY variable, and so you can't run any X (graphical) programs, e.g. Firefox.
I would suggest doing the HTTP connections yourself, in ruby, rather than trying to automate Firefox.

Answer 3

the crontab entry is wrong
it is like
#min hour day month dow user command
55 17 * * * ur_user_is_missing ruby /home/raguanu/Dropbox/nettie.rb >> /tmp/cron_test