app/routes.py

from flask import render_template, request, redirect, url_for, session, g
from app import app
from app.models import Questions

@app.route('/')
def home():
    return render_template('index.html', title='Home')

@app.route('/question/<int:id>', methods=['GET', 'POST'])
def question(id):
    form = QuestionForm()
    q = Questions.query.filter_by(q_id=id).first()
    if not q:
        return redirect(url_for('score'))
    if request.method == 'POST':
        option = request.form['options']
        if option == q.ans:
            session['marks'] += 10
        return redirect(url_for('question', id=(id+1)))
    form.options.choices = [(q.a, q.a), (q.b, q.b), (q.c, q.c), (q.d, q.d)]
    return render_template('question.html', form=form, q=q, title='Question {}'.format(id))

@app.route('/score')
def score():
    g.user.marks = session['marks']
    # db.session.commit()
    return render_template('score.html', title='Final Score')

@app.route('/logout')
def logout():
    session.pop('user_id', None)
    session.pop('marks', None)
    return redirect(url_for('home'))