user_flask_appengine.py

from flask import g, session
from google.appengine.api import users

class GuestUser(object):
    
    def email(self):
        return None
        
    def nickname(self):
        return 'Guest'
        
    def is_admin(self):
        return False

    def user_type(self):
        return 'guest'

class GoogleUser(object):
    
    def __init__(self, google_user):
        self.google_user = google_user
    
    def email(self):
        return self.google_user.email()
    
    def nickname(self):
        return self.google_user.nickname()
    
    def is_admin(self):
        return users.is_current_user_admin()

    def user_type(self):
        return 'google'
        
class TwitterUser(object):
    
    # add these to twitter user.
    
    def email(self):
        return None
    
    def nickname(self):
        return self.screen_name
    
    def is_admin(self):
        authorized_users = ['maxart', 'lukeinth']
        return self.screen_name in authorized_users

    def user_type(self):
        return 'twitter'

def get_current_user():
    user_id = session.get('user_id')
    user = None
    if user_id: 
        user = TwitterUser.get_by_user_id(session['user_id'])
    else:
        user = users.get_current_user()
        if user:
            user = GoogleUser(user)
    if not user:
        user = GuestUser()
    return user
    
@app.before_request
def add_user_to_globals():
    g.user = get_current_user()
    
@app.route('/some/path')
def some_path():
    user = g.user
    if user.is_admin():
        return render_template('admin.html', user=user)
    else:
        return render_template('normal.html', user=user)