Flask-login - AttributeError：'AnonymousUserMixin'对象没有属性'_sa_instance_state'

Question

我正在设置一个烧瓶应用程序来运行匿名在线实验。如何通过Login-manager的current_user对象跟踪匿名参与者？

当用户匿名时，current_user设置为AnonymousUserMixin。我试图给AnonymousUserMixin分配一个id变量（例如通过uuid.uuid4（））没有current_user=None但是它不再是一个ORM对象了。我试图按照这篇文章的第二个答案（How to track anonymous users with Flask）的建议，但我缺乏如何将描述的方法转换为实际代码的知识。

所以我最终得到错误消息'AnonymousUserMixin'对象没有属性'_sa_instance_state'，我似乎无法解决。

有关如何使用current_user对象与匿名用户的任何建议？

这里有一些相关的代码部分[编辑：代码根据@ Roch的建议调整]：

models.朋友

from website import db


# models for database structure
class DemographicData(db.Model):
    __tablename__ = 'demographic_data'
    id = db.Column(db.Integer, primary_key=True)
    gender = db.Column(db.String(1), nullable=False)
    age = db.Column(db.Integer, nullable=False)
    nationality = db.Column(db.String(50), nullable=False)
    # create relationships to the other models to link them to the demographicData
    consentRequest = db.relationship('ModalData', backref='participant_bref', lazy=True)


    def __repr__(self):
        return f"demographicData('{self.id}', '{self.gender}', '{self.age}', '{self.nationality}')"


class ModalData(db.Model):
    __tablename__ = 'modal_data'
    id = db.Column(db.Integer, primary_key=True)
    participantId = db.Column(db.Integer, db.ForeignKey('demographic_data.id'), nullable=False)
    consent = db.Column(db.String(3), nullable=False)

    def __repr__(self):
        return f"modalData('{self.participantId}', '{self.consent}')"

routes.朋友

from flask import render_template, url_for, redirect, request, session
from website import app, db
from website.models import DemographicData, ModalData
from website.questionnaires import DemographicsForm



@app.before_request
def make_session_permanent():
    session.permanent = True



# route to demographic information form
@app.route("/demographics", methods=['GET', 'POST'])
def demographics():
    form = DemographicsForm()
    if form.validate_on_submit():
        participant = DemographicData(gender=form.gender.data,
                                      age=form.age.data,
                                      nationality=form.nationality.data)
        session['anonymous_user_id'] = participant.id
        # save to database
        db.session.add(participant)
        db.session.commit()
        return redirect(url_for('megazine')) 
    return render_template('demographics.html', title='Demographic Information', form=form)



# route to a website I want to redirect to after demographics
@app.route("/megazine", methods=['GET', 'POST'])
def megazine():
    if request.method == 'POST':
        consentDecision = ModalData(participant_bref=session['anonymous_user_id'],
                                    consent=request.form['consentForm'])
        db.session.add(consentDecision)
        db.session.commit()
        return redirect(url_for('motivemag'))
    return render_template('/newswebsite_templates/megazine/index.html', title='Megazine')

Answer 1

您想在会话期间或会话结束后跟踪用户吗？

如果您需要在使用应用程序期间保留匿名用户的一些数据，您可以轻松使用Flask会话：http://flask.pocoo.org/docs/1.0/api/#flask.session

from flask import session

@app.route('/my_url1')
def my_view1():
    data = None
    if session.new:
         # ... do something like save data in the session
         session['foo'] = 'bar'
    # ... do something like read data in the session
    data = session['foo']
    return render_template('/my_template.html', data=data)

如果您希望在会话结束后保留​​用户的数据，我认为合乎逻辑的做法是动态创建用户并记录他。

from flask import session    
from models import User

@app.route('/my_url1')
def my_view1():
    data = None
    if session.new:
         user = User()
         session['anonymous_user_id'] = user.id
    else:
         user = User.query.get(session['anonymous_user_id'])
    # ... do whatever you like