CronPage.py

import os
import yaml
import urllib2
from facebook.webappfb import FacebookCanvasHandler, FacebookRequestHandler

class CronPage(FacebookRequestHandler):
    def get(self):
        self.canvas()

    def post(self):
        # Uhat widget id ref handler we're updating
        if self.request.get('wid').isdigit():
            wid = int(self.request.get('wid'))

        # Update images cache
        widgets = yaml.load(file('widgets.yaml', 'r'))["widgets"]
        for widget in widgets:
            if widget["id"] == wid:
                self.facebook.fbml.refreshImgSrc(widget["image"])

        self.response.out.write(("WID:%d image cache updated") % (wid))

    def canvas(self):
        if self.redirecting: return

        url_to_fetch = self.facebook.get_app_url() + "cron"

        fetcher = urllib2.build_opener()
        fetcher.addheaders = [('User-agent', 'GAE_CRON/1.0')]
        fetcher.open(url_to_fetch)