使用Werkzeug Security与Flask login_user实现用户登录时遭遇404及对象属性错误的求助

Hey there, let's break down what's going wrong here and get your login flow working smoothly!

The Root Cause #

That error message tells us exactly the issue: you’re passing a database query result tuple (row) directly to login_user(), but Flask-Login’s login_user() expects an object that implements specific properties and methods (like is_active, is_authenticated, etc.). A tuple doesn’t have these attributes, so the method throws an exception.

You already built a valid User_obj class that meets Flask-Login’s requirements—great work! The problem is just that you aren’t converting your database row into an instance of this class before calling login_user().

Step-by-Step Fix #

Let’s adjust your code to properly use your User_obj class:

1. Convert the database row to a User_obj instance
   When your password check passes, pull the id and email values from your row tuple and create a User_obj with them. Make sure the order matches your User_obj.__init__ method (id first, then email).

2. Pass the User_obj instance to login_user()
   Replace login_user(row) with login_user(user) where user is your new User_obj instance.

Here’s the corrected code snippet:

if check_password_hash(stored_hash, request.form.get('password')):
    print('logging in')
    # Convert database row to User_obj instance
    # Adjust indices if your row's field order is different!
    user = User_obj(row[0], row[1])
    # Now pass the valid User_obj to login_user
    login_user(user)
    return redirect(url_for('home', email=user_email, name=user_email))
else:
    return render_template('error.html')
except Exception as e:
    print(e)
    return render_template('invalid_details.html')

Quick Checks to Ensure Success #

• Double-check that your database row returns id and email in the order you’re passing to User_obj.__init__. If your query returns fields in a different order (e.g., email first), adjust the indices (like row[1], row[0]).
• Confirm your home route accepts the email and name parameters you’re passing via url_for (you mentioned the redirect works when login_user is commented out, so this is probably okay, but it’s good to verify).

Bonus: Simplify with UserMixin (Optional) #

If you want to skip writing those four user methods (is_authenticated, is_active, etc.) manually, you can use Flask-Login’s UserMixin class. Update your User_obj like this:

from flask_login import UserMixin

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

UserMixin provides default implementations for all required methods, so you don’t have to write them yourself.

内容的提问来源于stack exchange，提问作者Rolaxy