server.py

from flask import Flask, render_template, url_for, request, redirect
import csv
app = Flask(__name__)

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

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

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_form():
    if request.method == 'POST':
        try:
            data = request.form.to_dict()
            write_to_csv(data)
            return redirect('/thankyou')
        except:
            return "Did not save to database"
    else:
        return 'Something went wrong. Please try again.'