使用静态用户进行Flask-login始终会产生401-未经授权

Question

I am trying to build a super simple web app for my own use. I'll be the only user, so I don't feel the need to involve a database for user management. I'm trying to use flask-login, but even though my call to login_user succeeds, I'm still met with a 401-Unauthorized page after the redirect to a page with @login_required . Here is the entirety of my app:

from flask import Flask, render_template, request, flash, redirect, url_for
from flask.ext.login import LoginManager, login_user, logout_user, current_user, login_required, UserMixin

app = Flask(__name__, static_url_path="")
app.secret_key = "[redacted]"

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

class User(UserMixin):
    def __init__(self, id):
        self.id = id

nathan = User('nathan')

@login_manager.user_loader
def load_user(userid):
    if userid == 'nathan':
        return nathan
    else:
        return None

@app.route("/logout")
@login_required
def logout():
    logout_user()
    return redirect(url_for('login'))

@app.route('/')
@login_required
def index():
    return render_template('index.html')

@app.route("/login", methods=["GET", "POST"])
def login():
    if request.method == 'POST':
        if request.form['username'] == 'nathan'\
                and request.form['password'] == '[redacted]':
            login_user(nathan, remember=True)
            flash('logged in...', 'success')
            return redirect(request.args.get("next") or url_for("index"))
        else:
            flash('Incorrect username or password. Try again.', 'error')

    return render_template("login.html");

if __name__ == "__main__":
    app.run(host="0.0.0.0", debug=True)

I've verified that the login actually succeeds ( login_user returns true) and that load_user is returning the nathan object.

[EDIT] Also, I'm currently using the Flask development server, in case that's relevant.

Not sure where I'm going wrong. Thanks in advance!

Answer 1

Update:

Since a newer version(0.2.2) of Flask-Login this is no more an issue. Check out the changes in this commit.

If you are using an older version, read on.

---

The problem here is static_url_path="" . For Flask-Login to work you can not have an empty string static_url_path .

The following lines in the Flask-Login source(older version) reveal this:

if (current_app.static_url_path is not None and
    request.path.startswith(current_app.static_url_path)
):
    # load up an anonymous user for static pages
    _request_ctx_stack.top.user = self.anonymous_user()
    return

Since your static_url_path is "" the if condition evaluates to True , because of which every page you visit acts like a static page, and hence Flask-Login always loads an anonymous user, instead of continuing to load the actual user(using the load_user callback).

---

Also do not forget to uncomment #login_manager.login_view = "login"

---

If you still want to use the root folder of the app itself as the static folder, take a look at this solution, using SharedDataMiddleWare :

app.debug = True
if app.config['DEBUG']:
    from werkzeug import SharedDataMiddleware
    import os
    app.wsgi_app = SharedDataMiddleware(app.wsgi_app, {
      '/': os.path.dirname(__file__)
    })

if __name__ == "__main__":
    app.run(host="0.0.0.0")