Store your Flask sessions in DynamoDB - Python 3.5

DynamoSession.py

from uuid import uuid4
from datetime import datetime, timedelta
from flask.sessions import SessionInterface, SessionMixin
from werkzeug.datastructures import CallbackDict
import boto3


class DynamoSession(CallbackDict, SessionMixin):
    def __init__(self, initial=None, sid=None):
        CallbackDict.__init__(self, initial)
        self.sid = sid
        self.modified = False


class DynamoSessionInterface(SessionInterface):
    def __init__(self, host='', port=0,
                 db='sessions', collection='sessions'):
        client = boto3.client('dynamodb')
        self.store = client
        self.table = collection

    def open_session(self, app, request):
        sid = request.cookies.get(app.session_cookie_name)
        if sid:
            db_response = self.store.get_item(TableName=self.table,
                                              Key={'sid': {'S': sid}},
                                              ConsistentRead=True)
            stored_session = None
            if 'Item' in db_response:
                stored_session = dict()
                stored_session['expiration'] = datetime.fromtimestamp(int(db_response['Item']['expiration']['N']))
                stored_session['data'] = db_response['Item']['data']['M']
                stored_session['sid'] = db_response['Item']['sid']['S']
            if stored_session:
                now = datetime.now()
                if stored_session['expiration'] > now:
                    return DynamoSession(initial=stored_session['data'],
                                         sid=stored_session['sid'])
        sid = str(uuid4())
        return DynamoSession(sid=sid)

    def save_session(self, app, session, response):
        domain = self.get_cookie_domain(app)
        if not session:
            response.delete_cookie(app.session_cookie_name,
                                   domain=domain)
            return
        if self.get_expiration_time(app, session):
            expiration = self.get_expiration_time(app, session)
        else:
            expiration = int(((datetime.utcnow() + timedelta(hours=1))-datetime.utcfromtimestamp(0)).total_seconds())
        self.store.put_item(TableName=self.table,
                            Item={
                                'sid': {'S': str(session.sid)},
                                'data': {'M': session},
                                'expiration': {'N': str(expiration)}
                                }
                            )
        response.set_cookie(app.session_cookie_name, session.sid,
                            expires=self.get_expiration_time(app, session),
                            httponly=True, domain=domain)