Hi I don't know why "app" is not defined. I have a very simple app and try to run it:
run.py:
from flask import Flask
app = Flask(__name__)
import views
if __name__ == "__main__":
app.run(debug=True)
views.py:
#app.route('/')
def hello():
return 'Hello, World!'
If I try to run the server via "python run.py" I get the following error:
File "XXX\a\views.py", line 1, in <module>
#app.route('/')
NameError: name 'app' is not defined
You need to put all your routes in run.py.
This is because, you have declared app in run.py and in views.py you are trying to access it.
Following works for me:
run.py
from flask import Flask
app = Flask(__name__)
import view
view.py
from run import app
#app.route('/')
def hello():
return 'Hello, World!'
On terminal execute
export FLASK_ENV=development
export FLASK_APP=run.py
then finally flask run or python -m flask run.
Also, its a good idea to switch to flask run from app.run. See this
Related
I am new to flask and I have set up a simple flask example and two tests using pytest(see here). When I let run only one test it works, but if I run both tests it does not work.
Anyone knows why? I think I am missing here some basics of how flask works.
code structure:
app/__init__.py
from flask import Flask
def create_app():
app = Flask(__name__)
with app.app_context():
from app import views
return app
app/views.py
from flask import current_app as app
#app.route('/')
def index():
return 'Index Page'
#app.route('/hello')
def hello():
return 'Hello World!'
tests/conftest.py
import pytest
from app import create_app
#pytest.fixture
def client():
app = create_app()
yield app.test_client()
tests/test_app.py
from app import create_app
def test_index(client):
response = client.get("/")
assert response.data == b"Index Page"
def test_hello(client):
response = client.get("/hello")
assert response.data == b"Hello World!"
The problem is with your registration of the routes in app/views.py when you register them with current_app as app. I'm not sure how you would apply the application factory pattern without using blueprints as the pattern description in the documentation implies they are mandatory for the pattern:
If you are already using packages and blueprints for your application [...]
So I adjusted your code to use a blueprint instead:
app/main/__init__.py:
from flask import Blueprint
bp = Blueprint('main', __name__)
from app.main import views
app/views.py -> app/main/views.py:
from app.main import bp
#bp.route('/')
def index():
return 'Index Page'
#bp.route('/hello')
def hello():
return 'Hello World!'
app/__init__.py:
from flask import Flask
def create_app():
app = Flask(__name__)
# register routes with app instead of current_app:
from app.main import bp as main_bp
app.register_blueprint(main_bp)
return app
Then your tests work as intended:
$ python -m pytest tests
============================== test session starts ==============================
platform darwin -- Python 3.6.5, pytest-6.1.0, py-1.9.0, pluggy-0.13.1
rootdir: /Users/oschlueter/github/simple-flask-example-with-pytest
collected 2 items
tests/test_app.py .. [100%]
=============================== 2 passed in 0.02s ===============================
My Sample Flask Code (wsgitest.py):
from flask import Flask
from waitress import serve
app = Flask(__name__)
#app.route('/wait')
def index():
return ("<h3>Hello World</h3>")
if __name__ == '__main__':
serve(app, host='0.0.0.0', port=5000)
waitress
Version: 1.4.3
Error
ImportError: cannot import name 'serve' from 'waitress' (C:\.....\wsgitest.py)
if your your project has one file named waitress. Import resolves to your project file rather than waitress package
your code is ok. I copy your code to my idea, it's run successfully
I have a very small Flask app that is laid out as follows:
tinker/
main.py
/my_package
init.py
views.py
When I do tinker>python main.py everything runs fine. Here are the contents of each file:
main.py:
from my_package import app
app.run()
my_package/init.py:
from flask import Flask
app = Flask(__name__)
from my_package import views
my_package/views.py:
from my_package import app
#app.route('/')
def home():
return 'Ola!!!!!'
While all the above code runs fine when I try to modify it slightly by using a a create_app() code pattern, as in the below, views.py throws the following exception: "ImportError: cannot import name 'app' from 'my_package' " Is there a way to fix the problem without using Blueprints?
main.py:
from my_package import create_app
app = create_app()
app.run()
my_package/init.py:
from flask import Flask
def create_app():
app = Flask(__name__)
from my_package import views
return app
my_package/views.py:
from my_package import app
#app.route('/')
def home():
return 'Ola!!!!!'
You import the views within application context, then in the views you can use current_app.
in mypackage/__init__.py:
def create_app():
app = Flask(__name__)
with app.app_context():
from . import views
in mypackage/views.py:
from flask import current_app
#current_app.route('/')
def index():
return 'hello, world!'
init.py needs to be renamed to __init__.py
Move app = Flask(__name__) outside of the create_app method
Change to from . import app in views.py
But when I run the file it shows that flask could not import my python file.
I am having trouble to understand why flask shows this error.
THis is the image of my command prompt
https://imgur.com/TQaI6m3
This is the link of image of my command prompt. I am using Anaconda3
//This is the code in my flask_test.py file.
from flask import Flask
app = Flask(__name__)
#app.route("/")
def hello():
return "Hello World"
Try this code
from flask import Flask
app = Flask(__name__)
#app.route("/")
def hello():
return "Hello World!"
if __name__ == "__main__":
app.run()
So I'm following a beginners tutorial on Flask and for whatever reason am getting an error on what is essentially the very first step.
I first created an "app" directory where I created a python file for "init.py" which contains the following code:
from flask import Flask
app = Flask(__name__)
from app import routes
I then created a "routes.py" python file in the same directory:
from app import app
#app.route('/')
#app.route('/index')
def index():
return "Hello, World!"
Finally (and this is where the problem stems from), I created a python file named "microblog.py" which is located in the same folder as the "app" directory:
from app import app
I then go to my virtual environment and run (using cmd windows):
set FLASK_APP=microblog.py
So far so good, however when I try to run the following code in cmd:
flask run
I get the following error:
ImportError: cannot import name 'app' from 'app' (C:\Users\Grae_\microblog\app\__init__.py)
If any further clarification is needed, here are my file locations:
C:\Users\Grae_\microblog
C:\Users\Grae_\microblog\app
C:\Users\Grae_\microblog\__init__.py
C:\Users\Grae_\microblog\routes.py
C:\Users\Grae_\microblog\venv
C:\Users\Grae_\microblog\microblog.py
Apologies if this is really obvious, I'm just obviously very new to Flask and have been stuck on this for a while.
Thanks
The issue here is on python package "app". The directory should have a file named __init__.py instead of init.py.
For example, you rename the file init.py to __init__.py and replace content with below code it should work
from flask import Flask
app = Flask(__name__)
def start():
from app import routes
start()
You can do something like this:-
test.py
from flask import Flask
app = Flask(__name__)
#app.route("/")
def index():
return "Index!"
#app.route("/hello")
def hello():
return "Hello World!"
#app.route("/members")
def members():
return "Members"
#app.route("/members/<string:name>/")
def getMember(name):
return name</string:name>
if __name__ == "__main__":
app.run()
In command prompt, run the command-
python test.py
Try the URLs in your browser:
http://127.0.0.1:5000/
http://127.0.0.1:5000/hello
http://127.0.0.1:5000/members
http://127.0.0.1:5000/members/Karan/