pip install flask-login

import flask import Flask
from flask_login import LoginManager
app = Flask(__name__)
login_manager = LoginManager()
login_manager.init_app(app)

from flask_login import UserMixin,login_user
from sqlalchemy import create_engine,Column,String,Integer
from sqlalchemy.ext.declaractive import declaractive_base
engine = create_engine("mysql+pymysql://root:123456@localhost/pythondb")
Base = declaractive_base()
class User(Base,UserMixin):
  __tablename__ = "user"
  id = Column(Integer,primary_key=True)
  name = Column(String(16))
  password = Column(String(16))
  def login(self):
    login_user(self)

from flask_login import user_logged_in
@user_logged_in.connect_via(app)
def _logged_in(sender,user,**extra):
  ...

# login_manager为上面初始化的login_manager
@login_manager.user_loader
def user_loader(id):
  return session.query(User).filter_by(id=id).first()

from flask_login import login_required
@app.route("/user_info")
@login_required
def user_info():
  ...