#! /usr/bin/env python2
# SQLAlchemy uses to communicate with various types of DB---APIs and databases.
import os
import sys
from sqlalchemy import create_engine, asc
from sqlalchemy.orm import sessionmaker, relationship
from database_setup import Base, Restaurant, MenuItem, User
from flask import Flask, render_template, request, redirect, url_for
from flask import jsonify, flash
from flask import session as login_session
# login_session is working as a dictionary and save data for session when users login.
# generate random string namely (state) that identify each session.
app = Flask(__name__)
import random
import string
"""
Oauth is the standard used for authorisation.
flow object from client_secrets in json file store client_id , client_secret and other Oauth parameters.
json module provides an api for converting in memory python objects into serializable form called json.
"""
from oauth2client.client import flow_from_clientsecrets
from oauth2client.client import FlowExchangeError
from flask import make_response
import json
import requests
import httplib2
CLIENT_ID = json.loads(open('client_secrets.json', 'r').read())['web']['client_id']
APPLICATION_NAME = "Restaurant_Item_App"
# Connect to Database and create database session.
engine = create_engine('sqlite:///restaurantmenu.db')
Base.metadata.bind = engine
DBSession = sessionmaker(bind=engine)
session = DBSession()
"""
The function sessionmaker returns a class, binding the engine passed in the bind parameter.
So, after creating the class, you have to instantiate it.
"""
"""
state token is created which prevents anti-forgery attacks.
& store it in a session for later verification and provide security to users.
"""
@app.route('/login')
def showLogin():
state = ''.join(random.choice(string.ascii_uppercase + string.digits)
for x in xrange(32))
login_session['state'] = state
return render_template('login.html', STATE=state)
# return "the current session state is %s" %login_session['state']
@app.route('/menus/JSON')
def menusjson():
menu=session.query(MenuItem).all()
if login_session.has_key('email') and login_session['email']:
return jsonify(menuItems=[i.serialize for i in menu])
return redirect(url_for('mainpage'))
@app.route('/menus/<int:price>', methods=['GET', 'POST'])
def sort(price):
prc=session.query(MenuItem).filter_by(price=price)
return render_template('main.html', menu_item=prc)
@app.route('/menus/<string:name>', methods=['GET', 'POST'])
def sorted(name):
nam=session.query(MenuItem).filter_by(name=name)
return render_template('main.html', menu_item=nam)
"""
Created a function that handles the code sent back from call back method.
"""
@app.route('/gconnect', methods=['POST'])
def gconnect():
# validating state token
# *args is used to send a non-keyworded variable length argument list to the function
if request.args.get('state') != login_session['state']:
response = make_response(json.dumps('Invalid state parameter.'), 401)
response.headers['Content-Type'] = 'application/json'
return response
code = request.data
# authorization code is obtained
try:
oauth_flow = flow_from_clientsecrets('client_secrets.json', scope='')
oauth_flow.redirect_uri = 'postmessage'
credentials = oauth_flow.step2_exchange(code)
except FlowExchangeError:
response = make_response(
json.dumps('Failed to upgrade the authorization code.'), 401)
response.headers['Content-Type'] = 'application/json'
return response
# checking that the obtained access token is valid
access_token = credentials.access_token
url = ('https://www.googleapis.com/oauth2/v1/tokeninfo?access_token=%s'
% access_token)
h = httplib2.Http()
result = json.loads(h.request(url, 'GET')[1])
# If there was an error in the access token info, abort.
if result.get('error') is not None:
response = make_response(json.dumps(result.get('error')), 500)
response.headers['Content-Type'] = 'application/json'
return response
# Only the intended user uses the access_token .
gplus_id = credentials.id_token['sub']
if result['user_id'] != gplus_id:
response = make_response(
json.dumps("Token's user ID doesn't match given user ID."), 401)
response.headers['Content-Type'] = 'application/json'
return response
# verifying that the access_token is valid for this app.
if result['issued_to'] != CLIENT_ID:
response = make_response(
json.dumps("Token's client ID does not match app's."), 401)
print "Token's client ID does not match app's."
response.headers['Content-Type'] = 'application/json'
return response
stored_credentials = login_session.get('credentials')
stored_gplus_id = login_session.get('gplus_id')
if stored_credentials is not None and gplus_id == stored_gplus_id:
response = make_response(json.dumps(
'Current user is already connected.'), 200)
response.headers['Content-Type'] = 'application/json'
return response
# store the access token in the session for later use.
login_session['credentials'] = credentials.access_token
login_session['gplus_id'] = gplus_id
print login_session['credentials']
# get user Information through google account.
userinfo_url = "https://www.googleapis.com/oauth2/v1/userinfo"
params = {'access_token': credentials.access_token, 'alt': 'json'}
answer = requests.get(userinfo_url, params=params)
data = answer.json()
login_session['username'] = data['name']
login_session['picture'] = data['picture']
login_session['email'] = data['email']
# see if a user exist, if does'nt make a new one.
user_id = getUserID(login_session['email'])
if user_id is none:
user_id = createUser(login_session)
login_session['user_id'] = user_id
output = ''
output += '<h1>Welcome, '
output += login_session['username']
output += '!</h1>'
output += '<img src="'
output += login_session['picture']
output += ''' " style = "width: 250px;
height: 250px;
border-radius: 56px 55px 0px 200px;
-moz-border-radius: 56px 55px 0px 200px;
-webkit-border-radius: 56px 55px 0px 200px;
border: 0px solid #000000;">
'''
flash("You are now logged in as {name}".format(name=login_session['username']))
return output
"""
Disconnect connected user from their google account
which is done by rejecting the access token.
"""
@app.route('/gdisconnect')
def gdisconnect():
credentials = login_session.get('credentials')
# dumps takes an object and produces a string.
# credentials is empty then there is no one to disconnect.
if credentials is None:
response = make_response(
json.dumps('Current user not connected.'), 401)
response.headers['Content-Type'] = 'application/json'
return response
# execute http get req to revoke current token.
access_token = credentials.access_token
url = 'https://accounts.google.com/o/oauth2/revoke?token=%s' % access_token
h = httplib2.Http()
result = h.request(url, 'GET')[0]
if result['status'] == '200':
# Reset the user's sesson.
# disconnecting the users.
del login_session['credentials']
del login_session['gplus_id']
del login_session['username']
del login_session['email']
del login_session['picture']
# Response to indicate users has successfully logout from application.
print "Successfully disconnected"
# Back to lmain page as user should see items even though he has not sign in.
return render_template('main.html', restaurants=restaurants)
else:
# For whatever reason, the given token was invalid and something went wrong in disconnect process.
print "Failed to revoke token for given user."
return redirect(url_for('mainpage'))
@app.route('/')
@app.route('/menus', methods=['GET', 'POST'])
def mainpage():
showLogin()
menu=session.query(MenuItem).all()
if login_session.has_key('email') and login_session['email']:
return render_template('main.html', menu_item=menu_item, STATE = login_session['state'], name=login_session['username'], image=login_session['picture'])
@app.route('/fbconnect', methods=['POST'])
def fbconnect():
if request.args.get('state') != login_session['state']:
response = make_response(json.dumps('Invalid state parameter.'), 401)
response.headers['Content-Type'] = 'application/json'
return response
access_token = request.data
print "access token received %s " % access_token
app_id = json.loads(open('fb_client_secrets.json', 'r').read())[
'web']['app_id']
app_secret = json.loads(
open('fb_client_secrets.json', 'r').read())['web']['app_secret']
url = 'https://graph.facebook.com/oauth/access_token?grant_type=fb_exchange_token&client_id=%s&client_secret=%s&fb_exchange_token=%s' % (
app_id, app_secret, access_token)
h = httplib2.Http()
result = h.request(url, 'GET')[1]
# Use token to get user info from API
userinfo_url = "https://graph.facebook.com/v2.8/me"
"""
Due to the formatting for the result from the server token exchange we have to
split the token first on commas and select the first index which gives us the key : value
for the server access token then we split it on colons to pull out the actual token value
and replace the remaining quotes with nothing so that it can be used directly in the graph
api calls
"""
token = result.split(',')[0].split(':')[1].replace('"', '')
url = 'https://graph.facebook.com/v2.8/me?access_token=%s&fields=name,id,email' % token
h = httplib2.Http()
result = h.request(url, 'GET')[1]
# print "url sent for API access:%s"% url
# print "API JSON result: %s" % result
data = json.loads(result)
login_session['username'] = data["name"]
login_session['email'] = data["email"]
login_session['facebook_id'] = data["id"]
# The token must be stored in the login_session in order to properly logout
login_session['access_token'] = token
# Get user picture
url = 'https://graph.facebook.com/v2.8/me/picture?access_token=%s&redirect=0&height=200&width=200' % token
h = httplib2.Http()
result = h.request(url, 'GET')[1]
data = json.loads(result)
login_session['picture'] = data["data"]["url"]
# see if user exists
user_id = getUserID(login_session['email'])
if not user_id:
user_id = createUser(login_session)
login_session['user_id'] = user_id
output = ''
output += '<h1>Welcome, '
output += login_session['username']
output += '!</h1>'
output += '<img src="'
output += login_session['picture']
output += ''' " style = "width: 250px;
height: 250px;
border-radius: 56px 55px 0px 200px;
-moz-border-radius: 56px 55px 0px 200px;
-webkit-border-radius: 56px 55px 0px 200px;
border: 0px solid #000000;">
'''
flash('You are now logged in as {name}'.format(name=login_session['username']))
return output
@app.route('/fbdisconnect')
def fbdisconnect():
facebook_id = login_session['facebook_id']
# The access token must me included to successfully logout
access_token = login_session['access_token']
url = 'https://graph.facebook.com/%s/permissions?access_token=%s' % (facebook_id, access_token)
h = httplib2.Http()
result = h.request(url, 'DELETE')[1]
print "Successfully Disconnected"
return render_template('main.html', restaurants=restaurants)
"""
function which returns JSON APIs to view Restaurant Information.
"""
@app.route('/restaurant/<int:restaurant_id>/menu/JSON')
def restaurantMenuJSON(restaurant_id):
restaurant = session.query(Restaurant).filter_by(id=restaurant_id).one()
items = session.query(MenuItem).filter_by(
restaurant_id=restaurant_id).all()
return jsonify(MenuItems=[i.serialize for i in items])
"""
function which returns JSON APIs to view Restaurant Menu Item Information.
"""
@app.route('/restaurant/<int:restaurant_id>/menu/<int:menu_id>/JSON')
def menuItemJSON(restaurant_id, menu_id):
Menu_Item = session.query(MenuItem).filter_by(id=menu_id).one()
return jsonify(Menu_Item=Menu_Item.serialize)
@app.route('/restaurant/JSON')
def restaurantsJSON():
restaurants = session.query(Restaurant).all()
return jsonify(restaurants=[r.serialize for r in restaurants])
"""
Function shows all restaurant initially present in the database.
"""
@app.route('/')
@app.route('/restaurant/')
def showRestaurants():
restaurants = session.query(Restaurant).order_by(asc(Restaurant.name))
return render_template('restaurant.html', restaurants=restaurants)
"""
Function for adding new restaurant in the database.
"""
@app.route('/restaurant/new/', methods=['GET', 'POST'])
def newRestaurant():
"""
After you are logged in you need to protect your webpages that
you want only logged users to access your webpage this can be
done by verifying login_session has username variable else.
if you are not logged in will be redirect to login.html page.
"""
if 'username' not in login_session:
return redirect('/login')
if request.method == 'POST':
newRestaurant = Restaurant(
name=request.form['name'], image=request.form['image'], description=request.form['description'], user_id=login_session['user_id'])
session.add(newRestaurant)
# flash('New Restaurant %s Successfully Created' % newRestaurant.name)
flash('New Restaurant {name} Successfully Created'.format(name=newRestaurant.name))
session.commit()
return redirect(url_for('showRestaurants'))
else:
return render_template('newrestaurant.html')
"""
Function for deleting new restaurant in the database.
"""
@app.route('/restaurant/<int:restaurant_id>/delete/', methods=['GET', 'POST'])
def deleteRestaurant(restaurant_id):
restaurantToDelete = session.query(
Restaurant).filter_by(id=restaurant_id).one()
"""
After you are logged in you need to protect your webpages that
you want only logged users to access your webpage this can be
done by verifying login_session has username variable else.
if you are not logged in will be redirect to login.html page.
"""
if 'username' not in login_session:
return redirect('/login')
if (
restaurantToDelete and restaurantToDelete.user_id) != (
login_session['user_id']):
flash('You are not authorized to delete this restaurant')
return redirect(url_for('showRestaurants'))
if request.method == 'POST':
session.delete(restaurantToDelete)
flash('{name} Successfully Deleted'.format(name=restaurantToDelete.name))
session.commit()
return redirect(url_for('showRestaurants', restaurant_id=restaurant_id))
else:
return render_template(
'deleterestaurant.html', restaurant=restaurantToDelete)
"""
Function for editing existing restaurant in the database.
"""
@app.route('/restaurant/<int:restaurant_id>/edit/', methods=['GET', 'POST'])
def editRestaurant(restaurant_id):
editedRestaurant = session.query(
Restaurant).filter_by(
id=restaurant_id).one()
"""
After you are logged in you need to protect your webpages that
you want only logged users to access your webpage this can be
done by verifying login_session has username variable else.
if you are not logged in will be redirect to login.html page.
"""
if 'username' not in login_session:
return redirect('/login')
if (
editedRestaurant and editedRestaurant.user_id) != (
login_session['user_id']):
flash('You are not authorized to edit this restaurant')
return redirect(url_for('showRestaurants'))
if request.method == 'POST':
if request.form['name']:
editedRestaurant.name = request.form['name']
flash('Restaurant successfully edited {name}'.format(name=editedRestaurant.name))
return redirect(
url_for('showRestaurants', restaurant_id=restaurant_id))
else:
return render_template('editrestaurant.html', restaurant=editedRestaurant)
"""
Function showing the menu of the restaurant.
"""
@app.route('/restaurant/<int:restaurant_id>/')
@app.route('/restaurant/<int:restaurant_id>/menu/')
def showMenu(restaurant_id):
restaurant = session.query(
Restaurant).filter_by(
id=restaurant_id).one()
if restaurant is None:
flash("Restaurant does not exist")
return redirect(url_for('showRestaurants'))
items = session.query(MenuItem).filter_by(
restaurant_id=restaurant_id).all()
if 'username' not in login_session or restaurant.user_id:
return render_template(
'main.html',
items=items,
restaurant=restaurant)
else:
return render_template(
'menu.html',
items=items,
restaurant=restaurant
)
"""
Function to edit the existing menu item.
"""
@app.route(
'/restaurant/<int:restaurant_id>/menu/<int:menu_id>/edit',
methods=['GET', 'POST'])
def editMenuItem(restaurant_id, menu_id):
"""
After you are logged in you need to protect your webpages that
you want only logged users to access your webpage this can be
done by verifying login_session has username variable else.
if you are not logged in will be redirect to login.html page.
"""
if 'username' not in login_session:
return redirect('/login')
editedItem = session.query(MenuItem).filter_by(id=menu_id).one()
restaurantToDelete = session.query(Restaurant).filter_by(id=restaurant_id).one()
if restaurantToDelete is None:
flash('This restaurant does not exist')
return redirect(url_for('showRestaurants'))
if editedItem is None:
flash('This item does not exist')
return redirect(url_for('showMenu', restaurant_id=restaurant_id))
if restaurantToDelete.user_id != login_session['user_id']:
flash('You are not authorized to edit item from this restaurant menu')
return redirect(url_for('showMenu', restaurant_id=restaurant_id))
if request.method == 'POST':
if request.form['name']:
editedItem.name = request.form['name']
if request.form['description']:
editedItem.description = request.form['description']
if request.form['price']:
editedItem.price = request.form['price']
if request.form['image']:
editedItem.image = request.form['image']
if request.form['categories']:
editedItem.categories = request.form['categories']
session.add(editedItem)
session.commit()
flash('Menu Item Successfully Edited')
return redirect(url_for('showMenu', restaurant_id=restaurant_id))
else:
return render_template(
'editmenuitem.html',
restaurant_id=restaurant_id,
menu_id=menu_id, i=editedItem)
"""
Function create new menu item in the restaurant.
"""
@app.route('/restaurant/<int:restaurant_id>/menu/new/', methods=['GET', 'POST'])
def newMenuItem(restaurant_id):
"""
After you are logged in you need to protect your webpages that
you want only logged users to access your webpage this can be
done by verifying login_session has username variable else.
if you are not logged in will be redirect to login.html page.
"""
if 'username' not in login_session:
return redirect('/login')
restaurant = session.query(
Restaurant).filter_by(
id=restaurant_id).one()
if restaurant is None:
flash('This restaurant does not exist')
return redirect(url_for('showRestaurants'))
if login_session['user_id'] != restaurant.user_id:
flash('You are not authorized to create menu item for this restaurant')
return redirect(url_for('showMenu', restaurant_id=restaurant_id))
if request.method == 'POST':
newItem = MenuItem(
name=request.form['title'],
description=request.form['description'],
price=request.form['price'],
image=request.form['image'],
categories=request.form['categories'],
restaurant_id=restaurant_id,
user_id=restaurant.user_id)
session.add(newItem)
session.commit()
flash('New Menu {name} Item Successfully Created'.format(name=newItem.name))
return redirect(url_for('showMenu', restaurant_id=restaurant_id))
else:
return render_template('newmenuitem.html', restaurant_id=restaurant_id)
"""
Function to delete the existing menu item.
"""
@app.route(
'/restaurant/<int:restaurant_id>/menu/<int:menu_id>/delete',
methods=['GET', 'POST'])
def deleteMenuItem(restaurant_id, menu_id):
"""
After you are logged in you need to protect your webpages that
you want only logged users to access your webpage this can be
done by verifying login_session has username variable else.
if you are not logged in will be redirect to login.html page.
"""
if 'username' not in login_session:
return redirect('/login')
restaurantToDelete = session.query(Restaurant).filter_by(
id=restaurant_id).one()
if restaurantToDelete is None:
flash('This restaurant does not exist')
return redirect(url_for('showRestaurants'))
itemToDelete = session.query(MenuItem).filter_by(id=menu_id).one()
if itemToDelete is None:
flash('This item does not exist')
return redirect(url_for('showMenu', restaurant_id=restaurant_id))
if restaurantToDelete.user_id != login_session['user_id']:
flash(
'You are not authorized to delete item from this restaurant menu')
return redirect(url_for('showMenu', restaurant_id=restaurant_id))
if request.method == 'POST':
session.delete(itemToDelete)
session.commit()
flash('Menu Item Successfully Deleted')
return redirect(url_for('showMenu', restaurant_id=restaurant_id))
else:
return render_template('deleteMenuItem.html', item=itemToDelete)
"""
Creates a new user and allow him to login.
"""
def createUser(login_session):
newUser = User(name=login_session['username'],
email=login_session['email'],
picture=login_session['picture'])
session.add(newUser)
session.commit()
user = session.query(User).filter_by(email=login_session['email']).one()
return user.id
"""
Created a new user by fetching its email_id.
"""
def getUserID(email):
try:
user = session.query(User).filter_by(email=email).one()
return user.id
except:
return None
def getUserInfo(user_id):
user = session.query(User).filter_by(id=user_id).one()
return user
if __name__ == '__main__':
app.secret_key = 'super_secret_key'
app.debug = True
app.run(host='0.0.0.0', port=8000)
运行上述代码时出现的错误是：
Traceback (most recent call last):
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1997, in __call__
return self.wsgi_app(environ, start_response)
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1985, in wsgi_app
response = self.handle_exception(e)
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1540, in handle_exception
reraise(exc_type, exc_value, tb)
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1982, in wsgi_app
response = self.full_dispatch_request()
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1615, in full_dispatch_request
return self.finalize_request(rv)
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1630, in finalize_request
response = self.make_response(rv)
File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1725, in make_response
raise ValueError('View function did not return a response')
ValueError: View function did not return a response
答案 0 :(得分：1)
错误消息为您提供了足够多的提示：您的一个视图函数未返回响应（或显式返回None）。遗憾的是，WSGI在错误消息中既不包含端点也不包含uri，但您可以通过在before_request中添加一些日志记录来轻松处理它。
我快速滚动你的代码，发现了这个功能：
@app.route('/')
@app.route('/menus', methods=[...])
def mainpage():
showLogin()
menu=session.query(MenuItem).all()
if login_session.has_key('email') and login_session['email']:
return render_template('main.html', ...)
如果不满足条件，此功能显然不会返回任何内容。要解决此问题，请在结尾处返回错误页面或重定向。