In this example, we're going to be writing a sample KRunner plugin, that will just display the entered text in a messagebox. It is also demonstrated how to use a keyword, and how to add help to krunner.

After creating the plugin, we'll test it and finally package it up for distribution.

Building

First and foremost, make sure you have Python support enabled.

Next, you need to setup your plasmoid's development environment. For this example, our package will be called 'msgbox_runner'. Make a directory to put everything in. Plasma expects a certain set of files and directories to exist when loading a plasmoid package:

/ - The root of the package
- metadata.desktop - Metadata about the plasmoid
- contents/ - The directory plasma looks in for all your resources
  - code/ - 'code' type resources
    - main.py - The plugin's code. You can change this in metadata.desktop.

The metadata.desktop file

First, edit the metadata.desktop file so that it looks similar to this:

 [Desktop Entry]
Name=Msgbox runner
Comment=Sample python krunner plugin, that will show the entered text in a messagebox
Type=Service
Icon=dialog-information
ServiceTypes=Plasma/Runner
X-Plasma-API=python
X-Plasma-MainScript=code/main.py
X-KDE-PluginInfo-Author=<your name>  
X-KDE-PluginInfo-Email=<your email>
X-KDE-PluginInfo-Name=msgbox_runner
X-KDE-PluginInfo-Version=0.1
X-KDE-PluginInfo-Website=http://plasma.kde.org/
X-KDE-PluginInfo-License=LGPLv3
X-KDE-PluginInfo-EnabledByDefault=true

The last line is not strictly necessary, but convenient. Note that ServiceTypes value is different from other Plasma objects.

Code

The runner is a python class, and additionally you must provide a method for Plasma to create an instance.

 from PyKDE4 import plasmascript
from PyKDE4.plasma import Plasma
from PyKDE4.kdeui import KIcon, KMessageBox

class MsgBoxRunner(plasmascript.Runner):

    def init(self)
        # called upon creation to let us run any intialization
        # tell the user how to use this runner
        self.addSyntax(Plasma.RunnerSyntax("msg :q:", "Display :q: in a messagebox"))
        
    def match(self, context):
        # called by krunner to let us add actions for the user
        if not context.isValid():
            return
        
        q = context.query()

        # look for our keyword 'msg'
        if not q.startsWith("msg "):
             return

        # ignore less than 3 characters (in addition to the keyword)
        if q.length < 7:
            return
        
        # strip the keyword and leading space
        q = q[3:]
        q = q.trimmed()

        # now create an action for the user, and send it to krunner
        m = Plasma.QueryMatch(self.runner)
        m.setText("Message: '%s'" % q)
        m.setType(Plasma.QueryMatch.ExactMatch)
        m.setIcon(KIcon("dialog-information"))
        m.setData(q)
        context.addMatch(q, m)
        
    def run(self, context, match):
        # called by KRunner when the user selects our action,        
        # so lets keep our promise
        KMessageBox.messageBox(None, KMessageBox.Information, match.data().toString())


def CreateRunner(parent):
    # called by krunner, must simply return an instance of the runner object
    return MsgBoxRunner(parent)

It is as simple as that. Note that the CreateRunner function must be present, and return an instance of your runner class.

This code is about minimal. Plasmascript. Runner is a Plasma.AbstractRunner

Test the plugin

Now you should be ready to test the plugin, to install it, simply run (given the plugin is in directory "msgbox_runner")

$ plasmapkg --type runner --install msgbox_runner

Now press ALT + F2 and type 'msg hello world', and you should see the command "Message 'hello world' in the match list, and if you run it, a messagebox should show, greeting "hello world"

I have learned that krunner should be restarted between updates, so if you change your script and reinstall it, restart krunner:

$ plasmapkg --type runner --upgrade msgbox_runner
$ kquitapp krunner
$ # wait a moment
$ krunner

Distributing the plugin

Should you want to distribute your plugin, it is practical to pack it in a zip file that users can download:

$ zip -r msgbox_runner msgbox_runner

The zip archive can be installed with plasmapkg, just as the directory:

$ plasmapkg -t runner -i msgbox_runner.zip

That's all, happy coding :-)