GAE + Python2.7 + webapp2 + AJAX - ajax

Question

Are there any tutorials or code examples related to AJAX implementation for GAE + Python2.7 + webapp2.
I have tried to follow instructions below:
http://code.google.com/appengine/articles/rpc.html
but I receive the following error:
Traceback (most recent call last):
File "E:\dev\workspace\test\webapp2.py", line 1536, in __call__
rv = self.handle_exception(request, response, e)
File "E:\dev\workspace\test\webapp2.py", line 1530, in __call__
rv = self.router.dispatch(request, response)
File "E:\dev\workspace\test\webapp2.py", line 1278, in default_dispatcher
return route.handler_adapter(request, response)
File "E:\dev\workspace\test\webapp2.py", line 1101, in __call__
handler = self.handler(request, response)
TypeError: __init__() takes exactly 1 argument (3 given)
There is another similar discussion here:
Google App Engine Python Protorpc Error: __call__() takes exactly 1 argument (3 given)
heres is my code from Specialscope's example:
main.py
from BaseHandler import BaseHandler
from google.appengine.ext import blobstore
from google.appengine.ext.webapp import blobstore_handlers
import logging
from google.appengine.api import files
from google.appengine.api import images
import json
import webapp2
class FileuploadHandler(BaseHandler):
def get(self):
blobstore.create_upload_url('/static')
context={}
self.render_response("uploader.html",**context)
class FileDownloadHandler(blobstore_handlers.BlobstoreUploadHandler,BaseHandler):
def post(self):
upload_files=self.request.POST
#image=upload_files['file']
logging.error(upload_files)
keys=upload_files.keys()
imageurls=[]
for key in keys:
if key.find("uploadimage")!=-1:
image=upload_files[key]
file_name=files.blobstore.create(mime_type='image/jpg')
with files.open(file_name,'a') as f:
f.write(image.value)
files.finalize(file_name)
blob_key=files.blobstore.get_blob_key(file_name)
imageurls.append(images.get_serving_url(blob_key))
context={}
context['imagelinks']=imageurls
self.response.write(json.dumps(context))
app = webapp2.WSGIApplication([
('/upload', FileuploadHandler),
('/download', FileDownloadHandler),
], debug = True)
BaseHandler.py
import webapp2
import os
from webapp2_extras import jinja2
from google.appengine.ext import db
class BaseHandler(webapp2.RequestHandler):
#webapp2.cached_property
def jinja2(self):
# Returns a Jinja2 renderer cached in the app registry.
return jinja2.get_jinja2(app=self.app)
def render_response(self, _template, **context):
# Renders a template and writes the result to the response.
rv = self.jinja2.render_template(_template, **context)
self.response.write(rv)

Answer 1

The stack trace suggests that you have a url mapping in your WSGIApplication that has a group in it, but there's no handler with the corresponding arguments.
If you have
(r'/foo/(\s+)/(\s+)', FooHandler),
then you need
class FooHandler(webapp2.RequestHandler):
def get(self, arg1, arg2):
...
The doc you're using pre-dates Python 2.7 support by several years. Were I in your position, I'd be tempted to get the app working first on Python 2.5, then port to 2.7.

Answer 2

The problem is here:
import webapp2
app = webapp2.WSGIApplication([
('/upload', FileuploadHandler),
('/download', FileDownloadHandler),
], debug = True)
You can't use webapp2.WSGIApplication to construct your application, it doesn't understand protorpc. Instead, do this:
from protorpc.wsgi import service
app = service.service_mappings([
('/upload', FileuploadHandler),
('/download', FileDownloadHandler),
])