Evolution Plugin

This tutorial will show you how to write a mumbles plugin for Evolution that sends a notification when new mail is received.

Plugin Files

If you want to save yourself some typing (or indenting!) time, or just want to grab the plugin, the files for the tutorial are available here.

[edit: If you're using a newer version of Evolution (I have 2.12.1 in Gutsy), a new parameter has been added to the NewMail signal. I have updated the tutorial below to include handling of this parameter, however the files linked above do not yet include this update. Updates will appear shortly in svn

Requirements for this tutorial

• mumbles version 0.4
• dbus-monitor
• Evoultion

The DBus

As mumbles makes use of DBus, the first step in writing a plugin for mumbles is to look for the DBus signals, to which, we are able to connect. I like a simple command line application called dbus-monitor for this.

So, let's watch what happens on the DBus while running Evolution. First in a terminal type:

Next start Evolution.

In the output of dbus-monitor you should see (among other things) a few lines that look similar to:

Here, we see a DBus signal named 'MessageReading'. In our example, we're interested in what happens when new mail is received. So send your self a test message and click Send/Receive. You should then see, when your message arrives, in dbus-monitor something like:

[edit: depending on your version of Evolution you may not see the last uint32]

We see that when, new mail arrives, a signal is sent to the DBus called 'NewMail'. A few other things we'll need to note are:

• The signal name (member): NewMail
• The path: /org/gnome/evolution/mail/newmail
• The interface: org.gnome.evolution.mail.dbus.Signal
• And the two paramaters that are sent to the signal:
  • "mbox:/home/dot_j/.evolution/mail/local#Inbox"
  • "Inbox"
  • [edit: "uint23 1" for newer versions]

Writing the plugin

We'll make use of those shortly in the code for the plugin. We got what we needed from dbus-monitor, so go ahead and close it and create a new directory in your home directory for our plugin:

If you have mumbles installed locally and have dug around in the directories, you may have seen the structure of a mumbles plugin. Each plugin has a file named

and a directory named

The src directory contains another python file called

setup.py is just that - a setup file for our plugin and __init__.py in the src directory is the source file for our plugin.

Now let’s get down to business. Let’s setup that structure in a new directory for our plugin:

Next, create setup.py in your favorite editor:

And enter:

And save setup.py

Pretty straight forward setup here. We define our author, documentation and plugin version tags and add what we need in order to build our python egg (plugin). For more information about eggs and setuptools see here.

Now create our plugin source file

And enter:

And just 60 lines of code (with comments!) - not too bad, right? And we’re almost there. But first, we need to create that icon we used and put it where our plugin can find it.

So, create a plugins directory in your hidden .mumbles directory in your home folder. If you have run mumbles already, you will already have a directory called ~/.mumbles. If not, create that first, then create the plugin and plugin/icons directories there.

The default themes that come with mumbles will support an image around 20×20 pixels. So for this example, I used the Evolution icon I had in in /usr/share/icons/hicolor/22×22/apps/evolution.png

Build and install the plugin

This will use our setup.py file to create our plugin. After it runs, you should see a file named

in the dist directory that was created by the build process. Here the -py2.5 part of the filename refers to what version of python you are using (it may vary, but if you are able to start mumbles, should not matter).

The .egg file is our plugin, so the only thing left to do is copy that to the mumbles plugin directory.

Try it

That’s it! Now run mumbles and send yourself another email. You should see your new mail notification!

Thanks for following along. I hope you found this tutorial both helpful and interesting. And I hope it inspired you to write a plugin of your own. If you expand on this example, or write a new plugin for your favorite application be sure to let us know!

Files

Download tutorial files here.