Flask App Code

app.py

from flask import Flask, request, render_template, redirect, url_for
from form import CoefficientsForm
from utils import calculate_roots, save_to_db

app = Flask(__name__)
app.config['SECRET_KEY'] = '123'

@app.route('/', methods=['GET', 'POST'])
def calculate():
    form = CoefficientsForm()
    if form.validate_on_submit():
        return redirect(url_for('result', a=form.data['a'], b=form.data['b'], c=form.data['c']))
    return render_template('form.html', form=form)

@app.route('/result')
def result():
    save_to_db(request=request)
    return calculate_roots(a=request.args['a'], b=request.args['b'], c=request.args['c'])

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

form.html

  
<a>Solve <img src="http://latex.codecogs.com/svg.latex?ax^2+bx+c=0" border="0"/></a>
<br><br>
<form action="{{ url_for('calculate') }}" method="post">
    <a>a=</a>
    <input type="text" name="a">
    <a>b=</a>
    <input type="text" name="b">
    <a>c=</a>
    <input type="text" name="c">
    {{ form.csrf_token }}
    <input type="submit">
</form>

utils.py

import pymysql.cursors
import rds_config

def calculate_roots(a, b, c):
    """
    Calculates roots of quadratic equation of form `ax^2 + bx + c = 0`
    :param a: coefficient of x^2
    :param b: coefficient of x
    :param c: constant
    :return: roots if they exist
    """
    a, b, c = map(float, (a, b, c))

    if a == 0:
        return str(-c / b)

    discriminant = b**2 - 4 * a * c
    if discriminant < 0:
        return 'No real roots'

    x1 = (-b + discriminant ** 0.5) / (2 * a)
    x2 = (-b - discriminant ** 0.5) / (2 * a)

    if x1 == x2:
        return str(x1)

    return '{},{}'.format(x1, x2)

def save_to_db(request):
    db = pymysql.connect(host=rds_config.db_endpoint,
                         user=rds_config.db_username,
                         passwd=rds_config.db_password,
                         port=rds_config.db_port)
    cursor = db.cursor()
    cursor.execute('INSERT INTO mydb.inputs (a,b,c) VALUES (%s, %s, %s);' ,(request.args['a'], request.args['b'], request.args['c']))
    db.commit()
    db.close()