[Flask] Stuck with @login_required which breaks our app

[Stefan Knecht]

Thank you David, you led me down the right path! On that discord you
recommended was a super helpful user who identified the problem:

from app import login_manager

login_manager = LoginManager()
login_manager.init_app(app)
login_manager.login_view = "home_blueprint.login"

Commented out that second line that overwrites login_manager, and voila, it
started working. Stared at that code way too long and still can't believe I
didn't see that all this time.

Oh well.

Thanks, really appreciate it!


On Fri, Feb 25, 2022 at 4:51 PM David Nieder <davidnieder at gmx.de> wrote:

> Hello Stefan,
>
> I took your code and put together a minimal example but I could not
> reproduce your error: the redirect always happens for me.
> Looking at the code of Flask-Login, it seems to me that the only time
> 401 is returned is if login_view is not set. Maybe look at that
> again? But with your other dependencies there could be more going on.
>
> So the only tip I can give is: check if Flask-Login works with a
> stripped-down version of your code and add components back in.
> Here is what I used:
>
> from flask import Flask, request
> from flask_login import LoginManager, login_required, current_user,
> UserMixin
>
> app = Flask(__name__)
> app.secret_key = '123456'
>
> login_manager = LoginManager()
> login_manager.init_app(app)
> login_manager.login_view = 'login'
>
>
> @login_manager.user_loader
> def load_user(user_id):
>    return UserMixin
>
> @app.route('/index')
> def index():
>    return 'the index page'
>
> @app.route('/contents')
> @login_required
> def contents():
>    return 'the content page'
>
> @app.route('/login', methods=['GET', 'POST'])
> def login():
>    if not current_user.is_authenticated:
>      return 'current_user not authenticated'
>    return 'current_user authenticated'
>
>
>
> Good luck
> David
>
> P.S. there is flask community on discord which is a lot more active than
> this list. Maybe you can find more help there.
> https://discord.gg/pallets
>
>
>
> On 24.02.22 09:49, Stefan Knecht wrote:
>  > Hello all
>  >
>  > I'm hoping to end a week-long struggle by reaching out here.
>  >
>  > We've been evaluating and testing building flask apps to give our vast
>  > python command line tool arsenal a face lift.
>  >
>  > I've got the basics working with coreUI for templates and flask doing
> the
>  > core functionality. Or well, so it should.
>  >
>  > I've been following tutorials and the documentation, and as far as I can
>  > tell, we're doing everything correctly - yet it doesn't work anymore, as
>  > soon as I make use of @login_required.
>  >
>  > This is our routes.py:
>  >
>  > from app.home import blueprint
>  > from app.base.forms import LoginForm, CreateAccountForm
>  >
>  > from flask import Flask, current_app, render_template, redirect,
> url_for,
>  > request, jsonify, session
>  > from flask_login import LoginManager, login_required, current_user,
>  > login_user, logout_user
>  >
>  > from app import login_manager
>  > from app.base.models import User
>  >
>  > app = Flask(__name__)
>  >
>  > login_manager = LoginManager()
>  > login_manager.init_app(app)
>  > login_manager.login_view = 'home_blueprint.login'
>  >
>  >
>  > @login_manager.user_loader
>  > def load_user(user_id):
>  >    print(f"User loader {user_id}")
>  >    return User.get(user_id)
>  >
>  > @blueprint.route('/index')
>  > def index():
>  >    print("Index")
>  >    return render_template('index.html')
>  >
>  > @blueprint.route('/contents')
>  > @login_required
>  > def contents():
>  >    print("Contents")
>  >    return ('hello', 200)
>  >
>  >
>  > @blueprint.route('/login', methods=['GET', 'POST'])
>  > def login():
>  >
>  >    print(f"HEADER {request.headers}")
>  >
>  >    login_form = LoginForm(request.form)
>  >    if 'login' in request.form:
>  >
>  >      # read form data
>  >      username = request.form['username']
>  >      password = request.form['password']
>  >
>  >
>  >    if not current_user.is_authenticated:
>  >      return render_template( 'accounts/login.html', form=login_form)
>  >    return redirect(url_for('home_blueprint.index'))
>  >
>  > If I remove @login_required from the /contents route, everything works
>  > fine. As soon as I add it there (or anywhere else for that matter) we
> get
>  > nothing but 401 Unauthorized.
>  >
>  > This is what we use:
>  >
>  > $ pip3 list | grep -i flask
>  > Flask                  1.1.1
>  > Flask-Bootstrap        3.3.7.1
>  > Flask-Ext              0.1
>  > flask-ldap-login       0.3.0
>  > flask-ldap3-login      0.9.16
>  > Flask-Login            0.5.0
>  > Flask-Migrate          2.5.3
>  > flask-nav              0.6
>  > Flask-Session          0.3.2
>  > Flask-SimpleLDAP       1.4.0
>  > Flask-SQLAlchemy       2.4.4
>  > Flask-WTF              0.14.3
>  >
>  > Any hint would be greatly appreciated. The head hurts, the wall's
> already
>  > got a big hole in it.
>  >
>  >
>  > Stefan
>  >
>  >
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