Google App Engine on Silverlight - silverlight

Question

are there any good examples on how to use Google App Engine from Silverlight, preferably without writing custom webservices?
Cheers
Nik

Answer 1

Here is my approach based heavily on Scott Seely's post
Simply passes XML around, .xap is also served by GAE. I only just got this working yesterday so it is still work in progress.
Google:
app.yaml
application: wowbosscards
version: 1
runtime: python
api_version: 1
handlers:
- url: /WowBossCards.html
static_files: WowBossCards.html
upload: WowBossCards.html
mime_type: text/html
- url: /clientaccesspolicy.xml
static_files: clientaccesspolicy.xml
upload: clientaccesspolicy.xml
mime_type: text/xml
- url: /WowBossCards.xap
static_files: WowBossCards.xap
upload: WowBossCards.xap
mime_type: application/x-silverlight-app
- url: .*
script: wowbosscards.py
wowbosscards.py
#!/usr/bin/env python
import cgi
import datetime
import wsgiref.handlers
import os
import logging
import string
import urllib
from google.appengine.ext import db
from google.appengine.api import users
from google.appengine.ext import webapp
from google.appengine.ext.webapp import template
class Xml(db.Model):
xmlContent = db.TextProperty()
date = db.DateTimeProperty(auto_now_add=True)
class XmlCrud(webapp.RequestHandler):
def get(self, xmlType):
xmlKey = string.capitalize(xmlType)
xml = Xml.get_by_key_name(xmlKey)
self.response.headers['Content-Type'] = "application/xml"
self.response.out.write(xml.xmlContent)
def post(self, xmlType):
logging.debug("XmlCrud POST")
xmlKey = string.capitalize(xmlType)
xml = Xml.get_by_key_name(xmlKey)
if len(self.request.get('content')) > 0 :
xml.xmlContent = self.request.get('content')
else:
xml.xmlContent = self.request.body
xml.put()
self.redirect('/upload/' + xmlType)
def main():
Xml.get_or_insert("Bosses", xmlContent="<a>Bosses go here</a>")
Xml.get_or_insert("Dungeons", xmlContent="<a>Dungeons go here</a>")
application = webapp.WSGIApplication([
(r'/xml/(.*)', XmlCrud),
], debug=True)
wsgiref.handlers.CGIHandler().run(application)
if __name__ == '__main__':
main()
Silverlight:
private class RequestExtended
{
public VoidCall CallBack;
public WebRequest Request;
public Uri Host;
public RequestExtended(WebRequest request, VoidCall callBack, Uri host)
{
Request = request;
CallBack = callBack;
Host = host;
}
}
public static void ImportFromGoogle(Uri host, VoidCall callBack)
{
try
{
if (host.Host == "localhost")
{
host = new Uri(host.Scheme + #"://" + host.Host + ":8080");
}
var bossesCrud = new Uri(host, "/xml/bosses");
var bossesRequest = WebRequest.Create(bossesCrud);
bossesRequest.BeginGetResponse(BossesResponse, new RequestExtended(bossesRequest, callBack, host));
}
catch (Exception ex)
{
}
}
public static void BossesResponse(IAsyncResult result)
{
var requestExtended = result.AsyncState as RequestExtended;
try
{
WebResponse response = requestExtended.Request.EndGetResponse(result);
Stream responseStream = response.GetResponseStream();
byte[] bytes = new byte[response.ContentLength];
responseStream.Read(bytes, 0, bytes.Length);
responseStream.Close();
var enc = new System.Text.UTF8Encoding();
string xml = enc.GetString(bytes, 0, bytes.Length);
bosses = GetCollectionFromXmlString<BossCollection>(xml);
if (requestExtended.CallBack != null) requestExtended.CallBack();
}
catch (WebException we)
{
HttpWebResponse response = (HttpWebResponse)we.Response;
response.Close();
}
catch (Exception e)
{
}
}
public static void SaveBossesToGoogle(Uri host)
{
if (host.Host == "localhost")
{
host = new Uri(host.Scheme + #"://" + host.Host + ":8080");
}
var bossesCrud = new Uri(host, "/xml/bosses");
var request = WebRequest.Create(bossesCrud);
request.Method = "POST";
request.ContentType = "text/xml"; //"application/x-www-form-urlencoded";
request.BeginGetRequestStream(GetSaveBossesRequestStreamCallback, new RequestExtended(request, null, host));
}
static void GetSaveBossesRequestStreamCallback(IAsyncResult result)
{
var requestExtended = result.AsyncState as RequestExtended;
try
{
Stream stream = requestExtended.Request.EndGetRequestStream(result);
var xmlSerializer = new XmlSerializer(typeof(BossCollection));
var xmlText = new StringBuilder();
using (TextWriter textWriter = new StringWriter(xmlText))
{
xmlSerializer.Serialize(textWriter, Store.Bosses);
textWriter.Close();
}
var enc = new System.Text.UTF8Encoding();
var bytes = enc.GetBytes(xmlText.ToString());
stream.Write(bytes, 0, bytes.Length);
stream.Close();
requestExtended.Request.BeginGetResponse(SaveResponse, requestExtended);
}
catch (WebException we)
{
HttpWebResponse response = (HttpWebResponse)we.Response;
response.Close();
}
}
static void SaveResponse(IAsyncResult result)
{
var requestExtended = result.AsyncState as RequestExtended;
try
{
WebResponse response = requestExtended.Request.EndGetResponse(result);
if (requestExtended.CallBack != null) requestExtended.CallBack();
}
catch (WebException we)
{
HttpWebResponse response = (HttpWebResponse)we.Response;
response.Close();
}
}

Answer 2

I'm thinking about doing the same thing, but I've not come across anything yet.
I'm thinking about using JSON.net for the comms, so basically writing a REST service in GAE for the client to call, and maybe OAuth.NET for the authentication (unless I can find the .NET port of the google one, I've not looked yet)
Silverlight is basically just .NET, tho a lite version of it, so if you can find .NET code to do something, it should work, atleast somewhat, in SL :)
But thats as far as I've got - thinking about it. Sorry, can't be of more help yet!

Answer 3

I'm looking at this also. There are several REST projects for GAE, I haven't tried any of them out yet, but hope to in the next week or so.
http://code.google.com/p/app3/
http://code.google.com/p/gae-json-rest/
http://code.google.com/p/appengine-rest-server/

Answer 4

I couldn't find any examples getting Silverlight to work with google app's Java SDK, so here is my post.

Answer 5

Download the demo for Expression Blend. Check the included tutorial which shows how to create a gorgeous Silverlight interface in GUI mode and integrate it with the Bing search web service. Manipulating this example into a Google example should be trivial. Good luck! :)