Flask: For Loop not working in HTML template

Question

I am trying to display certain information on a template. Everything in the python code works perfectly but anything and everything inside the for loop is not getting displayed inside the template. I believe that I have passed everything correctly. Could someone please help me to display the tutor info in my 'display.html'? I also want to mention that whatever I am trying to display should be available for all users to see and not just me. The file will keep getting updated as more and more users register as a tutor. This should update and show everyone who has signed up to all the users. Code will be below. Thanks in advance!

main.py

    #main.py

    from flask import Flask, request, session, render_template, redirect, url_for, flash, get_flashed_messages
    from flask.globals import current_app
    from flask_login import LoginManager, login_user, login_required, logout_user, current_user, UserMixin
    from datetime import timedelta, datetime
    from werkzeug.security import generate_password_hash, check_password_hash
    import sqlite3
    from os import error, path
    from flask_sqlalchemy import SQLAlchemy
    from flask_mail import Mail, Message

    app = Flask(__name__)
    DB_NAME = "spark.db"
    app.config["SECRET_KEY"] = "1986319249872139865432"
    app.config['SQLALCHEMY_DATABASE_URI'] = f"sqlite:///{DB_NAME}"
    app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = False

    db = SQLAlchemy(app)
    db.init_app(app)

    def create_database(app):
        if not path.exists(DB_NAME):
            db.create_all(app=app)
            print("Created Database!")

    class Tutor(db.Model, UserMixin):
        id = db.Column(db.Integer, primary_key=True)
        user_id = db.Column(db.Integer, db.ForeignKey('user.id'))
        tremail = db.Column(db.String(10000))
        trusername = db.Column(db.String(1200))
        subjects = db.Column(db.String(1200))
        session_length = db.Column(db.String(1200))


    class User(db.Model, UserMixin):
        id = db.Column(db.Integer, primary_key=True)
        email = db.Column(db.String(150), unique=True)
        username = db.Column(db.String(150))
        password = db.Column(db.String(150))
        tutors = db.relationship('Tutor')


    create_database(app)

    login_manager = LoginManager()
    login_manager.login_view = 'login'
    login_manager.init_app(app)
    @login_manager.user_loader
    def load_user(id):
        return User.query.get(int(id))


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

    @app.route("/login", methods=["GET", 'POST'])
    def login():
        if request.method == "POST":
            email = request.form.get('email')
            password = request.form.get('password')

            user = User.query.filter_by(email=email).first()
            if user:
                if check_password_hash(user.password, password):
                    flash('Login successful!', category="success")
                    login_user(user, remember=True)
                    return redirect(url_for("home"))
                else:
                    flash('Incorrect password! Please try again.', category="error")
            else:
                flash("Account does not exist. Please register to continue.", category="error")


        return render_template("login.html", user=current_user)

    @app.route("/register", methods=["GET", "POST"])
    def register():
        if request.method == 'POST':
            email = request.form.get('email')
            username = request.form.get('username')
            password1 = request.form.get('password1')
            password2 = request.form.get('password2')

            user = User.query.filter_by(email=email).first()
            if user:
                flash("Email already exists.", category="error")
            elif len(email) < 4:
                flash("Email must be greater than 3 characters.", category="error")
            elif len(username) < 2:
                flash("Username must be greater than 1 character.", category="error")
            elif password1 != password2:
                flash("Passwords do not match! Please try again.", category="error")
            elif len(password1) < 8:
                flash("Password must be greater than 7 characters.", category="error")
            else:
                new_user = User(email=email, username=username, password=generate_password_hash(password1, method='sha256'))
                db.session.add(new_user)
                db.session.commit()
                login_user(new_user, remember=True)
                flash("Account successfully created!", category="success")
                return redirect(url_for('home'))

        return render_template("register.html", user=current_user)

    @app.route("/logout")
    @login_required
    def logout():
        logout_user()
        flash("Logged out succcessfully!", category="success")
        return redirect(url_for('login'))

    @app.route("/selection")
    @login_required
    def selection():
        return render_template("selection.html")

    @app.route("/tutorform", methods=['GET', 'POST'])
    @login_required
    def tutorform():
        if request.method == 'POST':
            tremail = request.form.get('tremail')
            trusername = request.form.get('trusername')
            subjects = request.form.get('subjects')
            session_length = request.form.get('session_length')

            new_tutor = Tutor(user_id=current_user.id, tremail=tremail, trusername=trusername, subjects=subjects, session_length=session_length)
            db.session.add(new_tutor)
            db.session.commit()
            flash('Entry has been saved!', category='success')
            return redirect(url_for("display"))
        
        return render_template("tutorform.html", user=current_user)

    @app.route("/tutoreeform", methods=['GET', 'POST'])
    @login_required
    def tutoreeform():
        if request.method == 'POST':
            flash("Tutoree Entry Successful!", category='success')
            return redirect(url_for("display"))

        return render_template("tutoreeform.html")

    @app.route("/display")
    @login_required
    def display():
        users = Tutor.query.all()

        for user in users:
            print(user.tremail)
            print(user.trusername)
            print(user.subjects)
            print(user.session_length)

        return render_template("display.html", users=users)


    if __name__ == '__main__':
        db.create_all()
        app.run(debug=True)

display.html

{% extends "base.html" %}
{% block title %}SparkWIT | | Available Tutors{% endblock %}

{% block content %}

<center><h1 style="color: beige; background-color: rgba(54, 65, 165, 0.466);"><b><i>Available Tutors</i></b></h1></center>
<table class="table">
    <thead>
      <tr>
        <th scope="col" style="color: beige;"> Tutor Emails</th>
        <th scope="col" style="color: beige;">Username</th>
        <th scope="col" style="color: beige;">Subjects</th>
        <th scope="col" style="color: beige;">Session Length</th>
      </tr>
    </thead>
    {% for user in users.tutors %}
    <tbody>
    <tr>
        <td style="color: beige;">{{ user.tremail }}</td>
        <td style="color: beige;">{{ user.trusername }}</td>
        <td style="color: beige;">{{ user.subjects }}</td>
        <td style="color: beige;">{{ user.session_length }}</td>
    </tr>
    </tbody>
    {% endfor %}
</table>
{% endblock %}

tutorform.html

    {% extends "base.html" %}
    {% block title %}SparkWIT | | Tutor Registration{% endblock %}

    {% block content %}

    <form method="POST">
        <center><h3 style="color: beige; background-color: rgba(54, 65, 165, 0.466);"><i><u>Tutor Entry</u></i></h3></center>
        <div class="form-group">
            <label for="tremail" style="color: azure;"><b>Email</b></label>
            <input 
            type="email"
            class="form-control" 
            id="tremail"
            name="tremail"
            placeholder="example@example.com"
            required />        
        </div>
        <div class="form-group">
            <label for="trusername" style="color: azure;"><b>Username</b></label>
            <input 
            type="text"
            class="form-control" 
            id="trusername" 
            name="trusername"
            placeholder="Username"
            required />        
        </div>
        <div class="form-group">
            <label for="subjects" style="color: azure;"><b>Subject</b></label>
            <input 
            type="text"
            class="form-control" 
            id="subjects" 
            name="subjects"
            placeholder="Ex. AP Physics"
            required />        
        </div>
        <div class="form-group">
            <label for="session_length" style="color: azure;"><b>Session Length</b></label>
            <input 
            type="text"
            class="form-control" 
            id="session_length"
            name="session_length"
            placeholder="Ex. 1.5 hours"
            required />        
        </div>
        <div class="form-group form-check">
            <input type="checkbox" class="form-check-input" id="agree" name="agree" required>
            <label class="form-check-label" for="agree" required><mark>I agree to conduct all sessions virtually for the tutoree's and my safety</mark></label>
        </div>
        <br>
        <button type="submit" class="btn btn-dark">Submit</button>
    </form>

    {% endblock %}

Answer 1

In the HTML file, the for loop should be like {% for user in users %} because to display the user details, we need to loop on the data item we are passing in the render_template function as parameter.