server.py

# Flask and sqlalchemy imports
from flask import (Flask, render_template, request, redirect, url_for, flash,
                   jsonify)
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from database_setup import Base, User, Category, Item
from functools import wraps

# OAuth stuff
from flask import session as login_session
import random
import string

# Imports for G-Connect stuff
from oauth2client.client import flow_from_clientsecrets
from oauth2client.client import FlowExchangeError
import httplib2
import json
from flask import make_response
import requests

# Token for Google authentication
CLIENT_ID = (json.loads(open('client_secrets.json', 'r').read())
             ['web']['client_id'])

# Flask setup
app = Flask(__name__)

# SQLAlchemy setup
engine = create_engine('sqlite:///itemcatalog.db')
Base.metadata.bind = engine
DBSession = sessionmaker(bind=engine)
session = DBSession()


@app.route('/#/')
def showLogin():
    """Directs user to login page for authentication"""
    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)


@app.route('/gconnect', methods=['POST'])
def gconnect():
    """Authenticate user through Google"""
    # Validate state token
    if request.args.get('state') != login_session['state']:
        response = make_response(json.dumps('Invalid state parameter'), 401)
        response.headers['Connect-Type'] = 'application/json'
        print "The states match!"
        return response

    # Obtain authorization code
    code = request.data

    try:
        # Upgrade the authorization code into a credentials object
        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['Connect-Type'] = 'application/json'
        return response

    # Check that 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')), 501)
        response.headers['contentType'] = 'application/json'

    # Verify that the access token is used for the intended user.
    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['Connect-Type'] = 'application/json'
        return response

    # Check to see if user is already logged in.
    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['Connect-Type'] = 'application/json'

    # Store the access token in the session for later use.
    login_session['credentials'] = credentials
    login_session['gplus_id'] = gplus_id

    # Get user info
    userinfo_url = "https://www.googleapis.com/oauth2/v1/userinfo"
    params = {'access_token': credentials.access_token, 'alt': 'json'}
    answer = requests.get(userinfo_url, params=params)
    # print answer.text # Print Google response for debugging
    data = json.loads(answer.text)

    login_session['username'] = data['name']
    login_session['picture'] = data['picture']
    login_session['email'] = data['email']
    login_session['provider'] = 'google'

    # Check if email exists and if not, create a new user
    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: 300px; height: 300px; border-radius: 150px; \
                -webkit-border-radius: 150px; -moz-border-radius: 150px;"> '
    flash_message = "You are now logged in as %s" % login_session['username']
    flash(flash_message)
    return output


@app.route('/gdisconnect')
def gdisconnect():
    """Sign out user authenticated through Google"""
    credentials = json.loads(login_session['credentials'].to_json())
    access_token = credentials['access_token']
    # print 'In gdisconnect access token is %s' % access_token
    # print 'User name is: %s ' % login_session['username']
    if access_token is None:
        print 'Access Token is None'
        response = make_response(json.dumps('Current user not connected.'),
                                 401)
        response.headers['Content-Type'] = 'application/json'
        return response
    url = 'https://accounts.google.com/o/oauth2/revoke?token=%s' % access_token
    h = httplib2.Http()
    result = h.request(url, 'GET')[0]
    # print 'result is '
    # print result
    if result['status'] == '200':
        # del login_session['access_token']
        # del login_session['gplus_id']
        del login_session['username']
        del login_session['email']
        del login_session['picture']
        response = make_response(json.dumps('Successfully disconnected.'), 200)
        response.headers['Content-Type'] = 'application/json'
        print response
        flash_string = "You have been logged out"
        flash(flash_string)
        return redirect(url_for('showCategories'))
    else:
        del login_session['username']
        del login_session['email']
        del login_session['picture']
        response = make_response(json.dumps('Failed to revoke token for given \
                                user.', 400))
        response.headers['Content-Type'] = 'application/json'
        return response


def login_required(f):
    @wraps(f)
    def decorated_function(*args, **kwargs):
        if 'username' in login_session:
            return f(*args, **kwargs)
        else:
            flash_string = "Sign-in required for access"
            flash(flash_string)
            return redirect('/#/')
    return decorated_function


@app.route('/')
@app.route('/catalog')
def showCategories():
    """Display all categories in database"""
    categories = session.query(Category).all()
    return render_template('categories.html', categories=categories,
                           login_session=login_session)


@app.route('/category/<category_name>')
def showItemList(category_name):
    """Display all items under a category"""
    category = session.query(Category).filter_by(name=category_name).one()
    items = session.query(Item).filter_by(category_id=category.id).all()
    return render_template('itemlist.html', category=category, items=items,
                           login_session=login_session)


@app.route('/category/<category_name>/<item_name>')
def showItemPage(category_name, item_name):
    """Display item page"""
    category = session.query(Category).filter_by(name=category_name).one()
    item = session.query(Item).filter_by(category_id=category.id,
                                         name=item_name).one()
    return render_template('itempage.html', category=category, item=item,
                           login_session=login_session)


@app.route('/category/new/', methods=['GET', 'POST'])
@login_required
def newCategory():
    """Create new category"""
    if request.method == 'POST':
        newCategory = Category(name=request.form['name'],
                               description=request.form['description'])

        # Initialize duplicate name flag to false
        name_exists = False

        # Check if category name has been taken already
        categories = session.query(Category).all()
        for category in categories:
            if str(category.name) == newCategory.name:
                # Set duplicate name flag
                name_exists = True

        if name_exists is True:
            # Name has been taken, reload same page and flash message
            flash_string = ("%s is already in use. Provide a different name" %
                            newCategory.name)
            flash(flash_string)
            return redirect(url_for('newCategory'))
        else:
            session.add(newCategory)
            session.commit()
            flash("New category created!")
            return redirect(url_for('showCategories'))
    else:
        return render_template('newcategory.html')


@app.route('/category/<category_name>/item/new/', methods=['GET', 'POST'])
@login_required
def newItem(category_name):
    """Create new item"""
    category = session.query(Category).filter_by(name=category_name).one()
    if request.method == 'POST':
        newItem = Item(name=request.form['name'],
                       category_id=category.id,
                       description=request.form['description'],
                       user_id=login_session['user_id'])

        # Initialize duplicate name flag
        name_exists = False

        # Check if item name has been taken already
        items = session.query(Item).all()
        for item in items:
            if str(item.name) == newItem.name:
                # Set duplicate name flag
                name_exists = True

        if name_exists is True:
            # Name has been taken, reload same page and flash message
            flash_string = ("%s is already in use. Provide a different name" %
                            newItem.name)
            flash(flash_string)
            return redirect(url_for('newItem', category_name=category.name))
        else:
            session.add(newItem)
            session.commit()
            flash_string = "%s has been added to the list" % newItem.name
            flash(flash_string)
            return redirect(url_for('showItemList',
                            category_name=category.name))
    else:
        return render_template('newitem.html', category=category)


@app.route('/category/<category_name>/item/<item_name>/edit/',
           methods=['GET', 'POST'])
@login_required
def editItem(item_name, category_name):
    """Edit existing item"""
    category = session.query(Category).filter_by(name=category_name).one()
    editedItem = session.query(Item).filter_by(name=item_name).one()

    if request.method == 'POST':
        # Check if user is the owner of the item
        if editedItem.user_id == login_session['user_id']:
            # User is the owner, allow edit to proceed
            if request.form['name']:
                editedItem.name = request.form['name']
            if request.form['description']:
                editedItem.description = request.form['description']
            session.add(editedItem)
            session.commit()
            flash_string = "%s has been edited" % editedItem.name
            flash(flash_string)
            return redirect(url_for('showItemList',
                                    category_name=category.name))
        else:
            # User is not the ownder, edit cannot proceed
            flash_string = ("You do not have permission to edit %s." %
                            editedItem.name)
            flash(flash_string)
            return redirect(url_for('showItemList',
                            category_name=category.name))
    else:
        return render_template('edititem.html', category=category,
                               item=editedItem)


@app.route('/category/<category_name>/item/<item_name>/delete/',
           methods=['GET', 'POST'])
@login_required
def deleteItem(item_name, category_name):
    """Delete existing item"""
    category = session.query(Category).filter_by(name=category_name).one()
    deletedItem = session.query(Item).filter_by(name=item_name).one()

    if request.method == 'POST':
        # Check if user is the owner of the item
        if deletedItem.user_id == login_session['user_id']:
            # User is the owner, allow delete operation to proceed
            session.delete(deletedItem)
            session.commit()
            flash_string = "%s has been deleted" % deletedItem.name
            flash(flash_string)
            return redirect(url_for('showItemList',
                            category_name=category.name))
        else:
            # User is not the owner, do not allow delete operation to proceed
            flash_string = ("You do not have permission to delete %s." %
                            deletedItem.name)
            flash(flash_string)
            return redirect(url_for('showItemList',
                            category_name=category.name))
    else:
        return render_template('deleteitem.html', category=category,
                               item=deletedItem)


@app.route('/catalog.json')
def catalog_json():
    """JSON endnpoint displaying all categories and their respective items"""
    categories = session.query(Category).all()
    return jsonify(Category=[i.serialize for i in categories])


def createUser(login_session):
    """Create new authenticated user in local database"""
    users = session.query(User).all()
    id_num = len(users) + 1
    newUser = User(id=id_num,
                   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()
    print user
    return user.id


def getUserID(email):
    """Return user's ID from local database using authenticated email"""
    try:
        user = session.query(User).filter_by(email=email).one()
        return user.id
    except:
        return None


def getUserInfo(user_id):
    """Return all available information on user"""
    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=5000)