My flask app is based on Miguel Grinberg's mega tutorial XIV with some extra stuff and it was all working fine and could be accessed from browser on localhost:5000. I decided to switch to an application factory approach as per Grinberg's XV tutorial BUT with no blueprints. Now when I enter localhost:5000 I get a URL not found. I am guessing my routes.py is not being picked up for some reason.
I have thoroughly worked through Grinberg's XV tutorial and the associated code and aligned everything less blueprints. These are the links I have explored that I have based my current app on: -
https://blog.miguelgrinberg.com/post/the-flask-mega-tutorial-part-xv-a-better-application-structure
http://flask.pocoo.org/docs/1.0/tutorial/factory/
Dave W Smith's answer in Configure Python Flask App to use "create_app" factory and use database in model class
and others.
From what I have read implementing an application factory should be really simple. The examples work.
The flask server starts from the command prompt in a venv as always.
Here is my directory structure.
myapp
app.py
config.py
...
/app
__init__.py
routes.py
models.py
forms.py
...
Here is the code slightly simplified for clarity.
# app.py
#=============================================
from app import create_app, db
from app.models import User, Post
app = create_app()
@app.shell_context_processor
def make_shell_context():
return {'db': db, 'User': User, 'Post' :Post}
# __init__.py
#=============================================
...
import os
from flask import Flask, request, current_app
from flask_sqlalchemy import SQLAlchemy
from flask_migrate import Migrate
...
from config import Config
db = SQLAlchemy()
migrate = Migrate()
...
def create_app(config_class=Config):
app = Flask(__name__)
app.config.from_object(config_class)
db.init_app(app)
migrate.init_app(app, db)
...
# logging, email servers, etc configured
return app
from app import models
# routes.py
#=============================================
from datetime import datetime
from flask import render_template, flash, redirect, url_for, request, g, \
jsonify, current_app
...
from app import app, db
from app.forms import LoginForm, RegistrationForm, EditProfileForm,
PostForm,ResetPassword,RequestForm, ResetPasswordForm
from app.models import User, Post
...
@app.route('/', methods=['GET', 'POST'])
@app.route('/index', methods=['GET', 'POST'])
@login_required
def index():
form = PostForm()
if form.validate_on_submit():
...
page = request.args.get('page', 1, type=int)
...
return render_template('index.html', title=_('Home'), form=form,
posts=posts.items, next_url=next_url,
prev_url=prev_url)
@app.route ....
# models.py
#=============================================
from datetime import datetime
from hashlib import md5
from time import time
from flask import current_app
from flask_login import UserMixin
from werkzeug.security import generate_password_hash, check_password_hash
import jwt
from app import db, login
class User(UserMixin, db.Model):
id = db.Column(db.Integer, primary_key=True)
username = db.Column(db.String(64), index=True, unique=True)
...
This may be irrelevant but it is one thing I tried. Note in routes.py that I have from app import app, db, if I remove app and add from flask import current_app then the @app decorators show as undefined.
Another point, because its a problem with routes. If I change the last line of __init__.py to from app import routes, models I get a different error.
flask.cli.NoAppException
flask.cli.NoAppException: While importing "metapplica", an ImportError was raised:
Traceback (most recent call last):
File "c:\users\markko~1\dropbox\python\projects\metapp~1\venv\lib\site-packages\flask\cli.py", line 236, in locate_app
__import__(module_name)
File "C:\Users\Mark Kortink\Dropbox\Python\projects\metapplica\metapplica.py", line 1, in <module>
from app import create_app, db, cli
File "C:\Users\Mark Kortink\Dropbox\Python\projects\metapplica\app\__init__.py", line 75, in <module>
from app import routes, models
File "C:\Users\Mark Kortink\Dropbox\Python\projects\metapplica\app\routes.py", line 8, in <module>
from app import app, db
ImportError: cannot import name 'app' from 'app' (C:\Users\Mark Kortink\Dropbox\Python\projects\metapplica\app\__init__.py)
It was this error that led me to try the current_app change mentioned above.
I start the app like this.
cd C:\Users\...\myapp
venv\Scripts\activate
set FLASK_APP=app.py
set FLASK_DEBUG=1
flask run
I know the problem is probably really basic but can anyone see why the above code would give a URL not found or not be able to find the routes?
=== NEXT PHASE ================ Following the recommendations from @silver below my new names are: -
myapp
runapp.py
...
/mapp
__init__.py
...
I went through all my code and changed from app[.xxx] import yyy to from myapp[.xxx] import yyy. This flushed out a few new errors where I was referencing app which I fixed by substituting current_app.
My new error is
RuntimeError
RuntimeError: Working outside of application context.
This typically means that you attempted to use functionality that needed
to interface with the current application object in some way. To solve
this, set up an application context with app.app_context(). See the
documentation for more information.
Traceback (most recent call last)
File "C:\Users\Mark Kortink\Dropbox\Python\projects\myapp\runapp.py", line 1, in <module>
from mapp import create_app, db, cli
File "C:\Users\Mark Kortink\Dropbox\Python\projects\myapp\mapp\__init__.py", line 75, in <module>
from mapp import routes, models
File "C:\Users\Mark Kortink\Dropbox\Python\projects\myapp\mapp\routes.py", line 16, in <module>
@current_app.before_request
app.pyand a package namedappin one folder won't work. - Klaus D.__init__.py->routes.py->__init__.py. Cirluar import don't work as expected. Unluckily flask is designed in a way that requires taking this into account. - Klaus D.app_packageat the top level,app_name.pyas the FLASK_APP entry point, andapp_internalsas the inner directory. - silver