server.py

from flask import Flask, render_template, url_for, request, redirect
import csv

app = Flask(__name__)
print(__name__)

@app.route('/')
def my_home():
    return render_template('index.html')

@app.route('/<string:page_name>')
def html_page(page_name):
    return render_template(page_name)

def write_to_file(data):
    with open('database.txt', mode='a') as database:
        email = data["email"]
        subject = data["subject"]
        message = data["message"]
        file = database.write(f'\n{email}, {subject}, {message}')

def write_to_csv(data):
    with open('database.csv', newline='', mode='a') as database2:
        email = data["email"]
        subject = data["subject"]
        message = data["message"]
        csv_writer = csv.writer(database2,delimiter=',',
                                quotechar='"',
                                quoting=csv.QUOTE_MINIMAL)
        csv_writer.writerow([email,subject,message])


@app.route('/submit_form', methods=['POST', 'GET'])
def submit():
    if request.method == 'POST':
        try:
            data = request.form.to_dict()
            write_to_csv(data)
            return redirect('/thankyou.html')
        except:
            return 'did not save to db'
    else:
        return "oops, something went wrong"