I just started using the new beta version of CS50 IDE. I tried to run my final project from last year, but when I run Flask I get the following message:

"DeprecationWarning: 'werkzeug.contrib.cache' is deprecated as of version 0.15 and will be removed in version 1.0. It has moved to https://github.com/pallets/cachelib."

When I run Flask on the older IDE, with the exact same code, everything works fine.

Just FYI, I am importing the following in application.py:

import os
import sqlite3
import csv

from cs50 import SQL
from flask import Flask, flash, redirect, render_template, request, session, send_from_directory, send_file, after_this_request, url_for, Request
from flask_session import Session
from tempfile import mkdtemp
from werkzeug.exceptions import default_exceptions
from werkzeug.security import check_password_hash, generate_password_hash
from werkzeug.utils import secure_filename

and in helpers.py:

import requests
import urllib.parse
import ast
import csv
import os

from flask import redirect, render_template, request, session
from functools import wraps
from cs50 import SQL

I already installed cachelib ("pip install -U cachelib") as suggested from the link in the error message.

Thanks in advance for the help

1 Answer 1


Not having seen the rest of your application.py code, I'm going to assume you have something like this:

# Configure CS50 Library to use SQLite database
 db = SQL("sqlite:///database.db")

near the top. If so, make sure that it comes after your line


Another student had this deprecation issue and, for some reason I don't yet understand, if the db is set before you run Session(app) you get this error, but if it's moved directly after, you don't.

  • Thank you so much cusiouskiwi, you are a life saver. The problem was actually in the helper.py code. As you mentioned, I had the """db = SQL("sqlite:///database.db")""" code at the top. After moved it and put inside the only function that was using it, it worked fine. Thanks a lot!
    – Student1
    Jul 24, 2019 at 1:19

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