Write a Robot for Google Wave

In this article we will write a Robot which will send an
E-mail to a prede fined E-mail address whenever a new blip is created in a Wave.
Using this extension, you can notify yourself or others about recent activities
in Google Wave, even when you are not logged into it.  To deploy and test the
Robot, you will need access to a Google Wave Preview account. If you don't have
it already, you can request for one at https://services.google.com/fb/forms/wavesignup/.
Google has been sending more invitations than be-fore. So it is likely that you
may get one, sooner than later. We will be writing the code for the Robot using
Eclipse IDE in Fe-dora Linux 12 (released on November17th) Robots can be written
in Python as well as Java. In this article we use Java and deploy the Robot onto
Google App Engine.To deploy the Robot to the Google App En-gine services, first
you will need to create an application identifier at the Google App Engine's
website. Fire up a web browser say Firefox. Login using yourGoogle/GMail account
at: http://app en-gine. google.com/. Click on the button “Create an
Application”. Type in a unique application identifier for example, bli-palert.
Type in an Application Title, say, “Sends E-Mail on a New Blip” and click on
Save. Assuming that you have a running Fedora 12 installation, click on
System>Administration>Add/Remove Soft-ware menu. In the search box, type eclipse
and click on find. From amongst the list of packages displayed, select Fedora
Eclipse and click on Apply.

Follow the onscreen instructions. Once installed, launch
Eclipse from Applications>Programming>Eclipse menu. When prompted, select the
workspace as prescribed by Eclipse -/home/shekhar/workspace in my case.

Once Eclipse is launched, click on Help>Install New
Software.  On the subsequent window titled “Available Software”, click on blue
link 'Available Software Sites'. Look for the URL http://download.eclipse.org/releases/galileo
in the list of Software Sites. Select and click on Enable. Click on OK. Back on
the “Available Soft-ware” Window, type the URL http://dl.google. com/eclipse/
plugin/3.5in the field labeled “Work with:” . Click on Add. This will show
Plugin and SDKs in the bottom pane. Check the boxes against them and click on
Next. Follow the on-screen instructions. This will install the Google Wave
plugins for Eclipse and SDK. When prompted, restart Eclipse.

In Eclipse, click on File>New> Project. Expand Google in
the New Project window, select Web Application Project and click on Next. For
the Project Name type Wave Email Alert. Type incom.it4enterprise.wave (for
example) forthe Package. Click on Finish. Download all the .jar files from the
URL  http://code.google.com/p/wave-ro-bot-java-client/downloads/list and copy
the files to /home/shekhar/ work-space/Wave Email Alert/war/WEB-INF/lib/ .
Replace /home/shekhar with your home directory. In the Eclipse's proj-ect
explorer, navigate to war>WEB-INF>lib. Right click and click on Refresh.Next,
click on Project>Properties (on thetop menu). Select Java Build Path. Click
onAdd Jars. Navigate to Wave EmailAlert/war/WEB-INF/lib/ and select the JARs
(that you downloaded and copied).Click on OK. First we write a Java class which
will send an E-mail message. Note that this class does not use Google Waveor
Robot API. It is the typical code for sending E-mails from any Java application.

package com.it4enterprise.wave;... }

In the above code replacefoo@gmail.com with the Google/GMail
E-mail address that you used to login into the Google App Engine. Replacefoo@foo.com
with the E-Mail address on which you want to receive the alerts.

Google Wave is a web based, e-mail client like interface where you can see multiple Waves (discussions) which are threaded, and on the right you can see your contacts and Blips (messages) of participants in a particular Wave .

In the Eclipse's project explorer, expand the Wave Email
Alert> src. Right click on com.it4enterprise.wave and select New>Class. Type in
Emailer for the Name of the class. Write the above code in the class file.

The Robot's codeGoogle

Wave Robots are nothing but Java Servlet which implement the proces-sEvents( )
method of AbstractRobot-Servlet class, from the Google Wave API class. Following
is the code for a Robot which will use the Emailer class (seeabove) to send an
E-mail whenever a newBlip is created.

package com.it4enterprise.wave;... }
}

The above code uses the Emailer class to send an E-mail as
follows, with the subject as “Wave Updated”:

A new blip has been added to the wave - Blip in theWave>. Click to view the Wave Parsing through the code, the
line:

Wavelet wavelet = bundle.getWavelet();

gives a reference to the Wave and the line:

if (e.getType() == Event-Type.WAVELET_BLIP_CREATED)

Checks whether the event corresponds to creation of a new
Blip. Subsequently we get a reference to the root Blip— the first Blip in the
wave and send its text in the E-mail along with the URL of the Wave. Note the
snippet:

wavelet.getWaveId().replace("+","%252B")

Here we get the Wave ID and replacethe + so as to construct
a browser friendlyURL.

appcfg.py update