flask-restplus is broken by Werkzeug 1.0.0

[gil0109]

Sorry, I am an Ops guys and not a developer but I hope this helps..

Error Messages/Stack Trace

If applicable, add the stack trace produced by the error

  | Traceback (most recent call last):   | File "./manage.py", line 4, in <module>   | from qsystem import db, application   | File "/opt/app-root/src/qsystem.py", line 16, in <module>   | from flask_restplus import Api   | File "/opt/app-root/lib/python3.6/site-packages/flask_restplus/__init__.py", line 4, in <module>   | from . import fields, reqparse, apidoc, inputs, cors   | File "/opt/app-root/lib/python3.6/site-packages/flask_restplus/fields.py", line 17, in <module>   | from werkzeug import cached_property   | ImportError: cannot import name 'cached_property'

Environment

• Python version 3.6.
• flask-marshmallow==0.10.1
• flask-oidc==1.4.0
• flask-restplus==0.13.0

[R-Sarge]

I too am experiencing this issue from a fresh install.

$ python app.py 
Traceback (most recent call last):
  File "app.py", line 23, in <module>
    from flask_restplus import Resource, Api
  File "/home/user/programs/python_apps/api-testing/env/lib/python3.6/site-packages/flask_restplus/__init__.py", line 4, in <module>
    from . import fields, reqparse, apidoc, inputs, cors
  File "/home/user/programs/python_apps/api-testing/env/lib/python3.6/site-packages/flask_restplus/fields.py", line 17, in <module>
    from werkzeug import cached_property
ImportError: cannot import name 'cached_property'

Environment:
aniso8601==8.0.0
attrs==19.3.0
Click==7.0
Flask==1.1.1
flask-restplus==0.13.0
importlib-metadata==1.5.0
itsdangerous==1.1.0
Jinja2==2.11.1
jsonschema==3.2.0
MarkupSafe==1.1.1
pkg-resources==0.0.0
pyrsistent==0.15.7
pytz==2019.3
six==1.14.0
Werkzeug==1.0.0
zipp==2.1.0

Edit: Downgrading to Werkzeug to 0.16.0 (temporarily) resolved the issue.

[Dave-Lopper]

Same issue here

Traceback (most recent call last): File "manage.py", line 10, in <module> from application.boot.blueprints import BLUEPRINT as api_bp File "/application/boot/blueprints.py", line 4, in <module> from flask_restplus import Api File "/venv/lib/python3.7/site-packages/flask_restplus/__init__.py", line 4, in <module> from . import fields, reqparse, apidoc, inputs, cors File "/venv/lib/python3.7/site-packages/flask_restplus/fields.py", line 17, in <module> from werkzeug import cached_property ImportError: cannot import name 'cached_property' from 'werkzeug' (/venv/lib/python3.7/site-packages/werkzeug/__init__.py)

psycopg2-binary==2.8.3
mysqlclient==1.4.4
celery==4.3.0
coverage==4.5.4
factory-boy==2.12.0
Flask==1.1.1
Flask-Migrate==2.5.2
flask-restplus==0.13.0
Flask-Script==2.0.6
Flask-Seeder==0.1a2
Flask-SQLAlchemy==2.4.0
flake8==3.7.9
kombu==4.6.3
python-dotenv==0.10.3
pylint==2.4.4
redis==3.3.11
SQLAlchemy-Utils==0.34.2
sentry-sdk[flask]==0.13.1
Flask-Testing==0.7.1
gunicorn==19.9.0
uuid==1.30
nplusone==1.0.0
newrelic==5.2.2.130
scipy==1.3.2
pandas==0.25.3
Faker==2.0.4
Werkzeug==1.0.0

Many thanks in advance

[pransen]

Temporary workaround: use Werkzeug==0.16.1

[Bonsaikitt3n]

Temporary workaround: use Werkzeug==0.16.1
Worked for me too.

[gijswobben]

Found the cause, but not sure how to fix it (if anybody does, please do)...
Flask-restplus has a dependency on Flask:
Flask>=0.8
The latest version of Flask is 1.1.1 and that version of Flask has a dependency on Werkzeug like this:
Werkzeug>=0.15 (https://github.com/pallets/flask/blob/master/setup.py line 56)
Werkzeug release 1.0 yesterday, breaking flask-restplus.

[antespo]

It's because cached_property has to be explicitly imported from werkzeug.utils now. #738 fixes that but I believe an import in api.py needs to also be fixed.

[rglsk]

Fixed here #778 Awaiting for code review.

[fattybenji]

As #777 (comment) said, you can pin the werkzeug version to 0.16.1 in your project dependencies.

[ziirish]

This project should be considered dead as stated in #770
BUT, flask-restx is also impacted by this bug.
I'm working on a hotfix release as of now that will hopefully be available by tomorrow.

[gil0109]

@ziirish thank you. I will ask our dev team to move over. Thank you for taking on this project!

[sreekanth-anubolu]

Werkzeug package got new version(1.0.0) update today. The update is not backward compatible, many Flask based libraries are breaking.
A simple fix is that, install Werkzeug==0.16.0, which is working perfectly.
Install this version before installing flask or after it, doesn't really matter, things will work as expected.