ModuleNotFoundError: No module named 'flask_session'

Question

I have a simple python file that I am trying to set up to utilize sessions, when i run the file I am receiving the error below:

ModuleNotFoundError: No module named 'flask_session'

I believe I am importing the module properly, is there anything else that I can check to set this up properly?

from flask import Flask, render_template, request, session
from flask_session import Session

app = Flask(__name__)

app.config["SESSION_PERMANENT"] = False
app.config["SESSION_TYPE"] = "filesystem"

Session(app)

@app.route("/", methods=["GET", "POST"])
def index():
    if session.get("notes") is None:
        session["notes"] = []

    if request.method == "POST":
        note = request.form.get("note")
        session["notes"].append(note)

    return render_template("index.html", notes=notes)

Here is the traceback ( most recent call last )

File "c:\python37\lib\site-packages\flask\cli.py", line 325, in __call__
Open an interactive python shell in this frameself._flush_bg_loading_exception()

File "c:\python37\lib\site-packages\flask\cli.py", line 313, in _flush_bg_loading_exception
reraise(*exc_info)

File "c:\python37\lib\site-packages\flask\_compat.py", line 35, in reraise
raise value

File "c:\python37\lib\site-packages\flask\cli.py", line 302, in _load_app
self._load_unlocked()

File "c:\python37\lib\site-packages\flask\cli.py", line 317, in _load_unlocked
self._app = rv = self.loader()

File "c:\python37\lib\site-packages\flask\cli.py", line 372, in load_app
app = locate_app(self, import_name, name)

File "c:\python37\lib\site-packages\flask\cli.py", line 242, in locate_app
'\n\n{tb}'.format(name=module_name, tb=traceback.format_exc())

Do you installed it actually? Try `$ pip install flask-sessioin`. — Grey Li, Jul 13 '18 at 02:26

score 24 · Answer 1 · answered Mar 22 '19 at 02:19

24

I've first encountered this problem while doing Harvard's CS50x class. I'm using Linux and I've been using Python3, as it turns out I've installed Flask-Session for Python2. I don't know whether it also applies to Mac but I used the following instead:

$ pip3 install flask-session

Then you can check whether it's installed with pip's freeze command. After doing this my pylint in VSCode no longer gave an error.

answered Mar 22 '19 at 02:19

Gusti Scarlett Halima

349
2
4

THANK YOU!!! I was taking CS50 Fall 2022 course and got to Chapter 9 "Flask" and everything was going well until I got this same error. Instead of pulling my hair out and cussing for hours I did a GOOGLE search: ModuleNotFoundError: No module named 'flask_session' and found this and it worked. Thanks!!!!! – Dave Aug 27 '23 at 16:00

score 13 · Answer 2 · answered Nov 08 '18 at 20:22

I got the flask_session module not found a number of times and it took me 2 hours to find a fix after thousands of attempts. Well, I too visited a number of sites looking for a solution but didn't get any. I got this error while I was learning the online course cs50 web development on edx.org by Harvard and when I read the forum discussion on reddit I saw comments where they mentioned Harvard used a special server to make it work and I felt the pain of not going to Harvard but two hours later I'm screaming because I just found a solution that's no where on the internet.

You should not use from flask_session import Session

Instead use from flask_session.__init__ import Session

I cannot explain the terminology as to why we do this here but you can private message me if you want to understand why we do this. Happy Coding!

jeez man thanks a lot. I am taking the course and got stuck in the session part too. This should be the best answer to the OP's question. — Mahir Islam, Jul 29 '19 at 04:03

taaaato · Answer 3 · 2020-04-10T16:53:33.357

4

Be sure to have the extension installed:

pip install Flask-Session

oficial page with instructions

If you get the error "ModuleNotFoundError: No module named 'werkzeug.contrib'":

pip install werkzeug==0.16.0

The latest version is the 1.0.1 but only the 0.16.0 worked.

(where I found this solution) (official page)

edited Apr 10 '20 at 16:53

answered Apr 10 '20 at 16:38

taaaato

41
2

score 2 · Answer 4 · answered Nov 24 '18 at 13:37

2

simply goto terminal and type pip install flask_session , wait for installation, once done you are good to go. ( Also many other solutions do not work, look for red highlighted part in image. Once installed it works properly.)

answered Nov 24 '18 at 13:37

Amit

105
1
6

score 1 · Answer 5 · edited Dec 15 '18 at 02:15

1

I ran into the same error.

The following worked for me.

Install the extension with the following command:

$ easy_install Flask-Session

or alternatively, if you have pip installed:

$ pip install Flask-Session

edited Dec 15 '18 at 02:15

amanb

5,276
3
19
38

answered Dec 14 '18 at 22:02

Ajitesh Abhishek

21
1

score 1 · Answer 6 · answered May 07 '19 at 21:36

1

I got it for windows:

There's no the library "flask_session" (--is a directory--) in your directory ...venv\Lib\site-packages (virtual environment)

You just need copy it from C:\Users\your _user\AppData\Local\Programs\Python\Python37-32\Lib\site-packages and then paste it in venv\Lib\site-packages or where you have installed your virtual environment. Thats it and sorry for my english, greetings from Medellin Colombia.

answered May 07 '19 at 21:36

user11466962

11
1

Thanks, I needed this. I figured it out, but to improve a bit on the directions: I copied the files from within C:\Users\username\AppData\Local\Programs\Python\Python36\Lib\site-packages\flask_session to where I found venv (dir /s venv from C:\Users\username) to C:\Users\username\AppData\Local\Programs\Python\Python36\Lib\venv I also needed the from flask_session.__init__ import Session tip from another answer. Hope this helps someone! – JulieC Nov 01 '19 at 20:49

score 0 · Answer 7 · answered Jul 25 '18 at 21:12

0

Try to do following command instead of all go to terminal and type

$ easy_install Flask-Session

If it shows an error,use sudo before it , If it shows any error please let me know also feel free to upvote

answered Jul 25 '18 at 21:12

Vimal Raj

474
6
19

Onen simon · Answer 8 · 2018-10-14T19:05:10.113

0

Install the extension first using the following command $ pip install Flask-Session. You can read more on flask-session via https://pythonhosted.org/Flask-Session/

edited Oct 14 '18 at 19:05

answered Oct 14 '18 at 18:19

Onen simon

750
1
13
17

score 0 · Answer 9 · answered Mar 27 '20 at 14:06

0

For completeness, I will share my solution:

In my case installed everything with pip3 to make it work with python 3.7, only worked with vscode after uninstalling python 2 from the system and reopening vscode.

answered Mar 27 '20 at 14:06

DavidGaray

26
1

score 0 · Answer 10 · answered Mar 22 '23 at 04:09

0

Too many hours on this.

Try itsdangerous==1.1.0

as per https://github.com/fengsp/flask-session/issues/89

answered Mar 22 '23 at 04:09

Glen020

187
1
12

Please phrase this as an explained conditional answer, in order to avoid the impression of asking a clarification question instead of answering (for which a comment should be used instead of an answer, compare https://meta.stackexchange.com/questions/214173/why-do-i-need-50-reputation-to-comment-what-can-i-do-instead ). For example like "If your problem is ... then the solution is to .... because .... ." – Yunnosch Mar 22 '23 at 05:40

Daniel Carmona · Answer 11 · 2023-05-18T15:44:37.013

0

Looks like someone created a fork under Flask-Session2 that can be found in pip - Flask-Session

pip install Flask-Session2

Can be imported as follow:

from flask_session import Session

edited May 18 '23 at 15:44

answered May 18 '23 at 15:43

Daniel Carmona

1
2

score -1 · Answer 12 · answered Jul 12 '18 at 19:49

-1

Are you using this library? https://pythonhosted.org/Flask-Session/

The docs suggest importing it this way: from flask.ext.session import Session

answered Jul 12 '18 at 19:49

Michael Patterson

1,750
13
11

13

FWIW, I believe that doc is out of date. [`flask.ext.xxxx` is deprecated](http://flask.pocoo.org/docs/1.0/upgrading/#extension-imports) and should be using `flask_xxxx` instead. The path in the OPs questions Python 3.7, which `flask.ext.xxxx` does not work – Wondercricket Jul 12 '18 at 20:38
@Wondercricket, your suggestion finally fixed the problem for me. Thank you, so much! – HMLDude Jul 02 '19 at 20:21

ModuleNotFoundError: No module named 'flask_session'

12 Answers12