How do I...Write an extension using Google App Engine?

Creating your own extension only takes a few lines of code:

#!/usr/bin/env python

import cgi
import wsgiref.handlers

from google.appengine.api import users
from google.appengine.ext import webapp

from dekiext import *

class MyExtension(DekiExt):

	# this method is required
	def title(self): return "My Extension"

	# the following methods are optional
	def description(self): return "My Description"
	def namespace(self): return "my"
	def copyright(self): return "My Copyright"
	def label(self): return "MyExt"

	# function to export
	@function("str", "return user greeting")
	@param("str", "name of user (default: \"stranger\")", True)
	def hello(self, name):
		return "Hi " + (name or "stranger!")

def main():
	application = webapp.WSGIApplication([('/', MyExtension)], debug=True)
	wsgiref.handlers.CGIHandler().run(application)

if __name__ == "__main__":
	main()

Upload it to your account.  Now try it out by going to your application's URI. (e.g. http://dekiext.appspot.com)

<extension>
  <title>My Extension</title>
  <copyright>My Copyright</copyright>
  <description>My Description</description>
  <namespace>my</namespace>
  <function>
    <name>hello</name>
    <description>return user gretting</description>
    <uri protocol="xmlrpc">http://dekiext.appspot.com/hello.rpc</uri>
    <param name="name" type="str" optional="true">name of user (default: "stranger")</param>
    <return type="str" />
  </function>
</extension>

To add your newly created extension to Deki Wiki, follow these steps:

1. Open your Control Panel
2. Click on Service Management
3. Click on Remote
4. Select Extension from the dropdown menu
5. Enter a description for your extension
6. Paste in the URI
7. And click Add Service

Your users can now invoke extension functions directly from your Google App Engine application.