[Python] ImportError: cannot import name 'FileStorage' from the generated flask server

[kannkyo]

Description

When I run flask-server, I get bellow ImportError.

Traceback (most recent call last):
  File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "python-flask-server/swagger_server/__main__.py", line 3, in <module>
    import connexion
  File "python-flask-server/venv/lib/python3.6/site-packages/connexion/__init__.py", line 3, in <module>
    from .apis import AbstractAPI  # NOQA
  File "python-flask-server/venv/lib/python3.6/site-packages/connexion/apis/__init__.py", line 1, in <module>
    from .abstract import AbstractAPI  # NOQA
  File "python-flask-server/venv/lib/python3.6/site-packages/connexion/apis/abstract.py", line 14, in <module>
    from ..operation import Operation
  File "python-flask-server/venv/lib/python3.6/site-packages/connexion/operation.py", line 7, in <module>
    from .decorators import validation
  File "python-flask-server/venv/lib/python3.6/site-packages/connexion/decorators/validation.py", line 9, in <module>
    from werkzeug import FileStorage
ImportError: cannot import name 'FileStorage'

Swagger-codegen version

2.4.13

Swagger declaration file content or url

https://petstore.swagger.io/v2/swagger.json

Command line used for generation

I generated flask server from swagger-editor.

Steps to reproduce

I use venv and run swagger_server

python -m venv venv
source venv/bin/activate
pip3 install -r requirements.txt
python3 -m swagger_server

Related issues/PRs

spec-first/connexion#1149

Suggest a fix/enhancement

I can fix this bug when adding two line in reqirements.txt.

  connexion == 1.1.15
  python_dateutil == 2.6.0
  setuptools >= 21.0.0
+ Werkzeug == 0.12.2
+ flask == 0.10.1

[PabloCastellano]

I fixed this same issue by updating connexion to 2.x.x. The master branch already generates a requirements.txt file with an updated connexion version

[debragail]

I had this same issue with the latest clone.

[jturi]

I have the same FileStorage error using:

connexion==2.3.0
Flask==1.1.2
Werkzeug==1.0.1

During handling of the above exception, another exception occurred:
../../../venv/py37/lib/python3.7/site-packages/py/_path/local.py:704: in pyimport
    __import__(modname)
../../../venv/py37/lib/python3.7/site-packages/_pytest/assertion/rewrite.py:152: in exec_module
    exec(co, module.__dict__)
source_code/tests/conftest.py:6: in <module>
    from test_api.run import create_app
source_code/test_api/run.py:3: in <module>
    import connexion
../../../venv/py37/lib/python3.7/site-packages/connexion/__init__.py:5: in <module>
    from .apis import AbstractAPI  # NOQA
../../../venv/py37/lib/python3.7/site-packages/connexion/apis/__init__.py:1: in <module>
    from .abstract import AbstractAPI  # NOQA
../../../venv/py37/lib/python3.7/site-packages/connexion/apis/abstract.py:10: in <module>
    from ..operations import make_operation
../../../venv/py37/lib/python3.7/site-packages/connexion/operations/__init__.py:1: in <module>
    from .abstract import AbstractOperation  # noqa
../../../venv/py37/lib/python3.7/site-packages/connexion/operations/abstract.py:10: in <module>
    from ..decorators.response import ResponseValidator
../../../venv/py37/lib/python3.7/site-packages/connexion/decorators/response.py:12: in <module>
    from .validation import ResponseBodyValidator
../../../venv/py37/lib/python3.7/site-packages/connexion/decorators/validation.py:9: in <module>
    from werkzeug import FileStorage
E   ImportError: cannot import name 'FileStorage' from 'werkzeug'

Problem fixed doing:

pip uninstall Werkzeug connexion
pip install connexion==2.6.0

[ulidtko]

If you also want working tox tests, apply this patch:

diff --git i/requirements.txt w/requirements.txt
index b5bc506..c44cfa7 100644
--- i/requirements.txt
+++ w/requirements.txt
@@ -1,3 +1,3 @@
-connexion == 2.2.0
+connexion == 2.7.0
 python_dateutil == 2.6.0
 setuptools >= 21.0.0
diff --git i/test-requirements.txt w/test-requirements.txt
index 7f8d96e..3bff640 100644
--- i/test-requirements.txt
+++ w/test-requirements.txt
@@ -1,4 +1,4 @@
-flask_testing==0.6.1
+flask_testing
 coverage>=4.0.3
 nose>=1.3.7
 pluggy>=0.3.1

[jstockdi-marstone]

https://oss.sonatype.org/content/repositories/snapshots/io/swagger/codegen/v3/swagger-codegen-cli/3.0.23-SNAPSHOT/

Still has the requirements.txt set to connexion == 2.2.0

I believe you must be using the 2.X branch.