capsul-flask/capsulflask/payment.py

import stripe
import json
import time
import decimal
import re
import sys

from time import sleep
from datetime import datetime, timedelta
from flask import Blueprint
from flask import make_response
from flask import request
from flask import current_app
from flask import session
from flask import redirect
from flask import url_for
from flask import jsonify
from flask import flash
from flask import render_template
from werkzeug.exceptions import abort

from capsulflask.auth import account_required

from capsulflask.db import get_model
from capsulflask.btcpay import client as btcpay
from capsulflask.shared import my_exec_info_message, get_account_balance, average_number_of_days_in_a_month

bp = Blueprint("payment", __name__, url_prefix="/payment")

def validate_dollars(min: float, max: float):
  errors = list()
  dollars = None
  if "dollars" not in request.form:
    errors.append("dollars is required")
  else:
    dollars = None
    try:
      dollars = float(request.form["dollars"])
    except:
      errors.append("dollars must be a number")

    #current_app.logger.info(f"{str(dollars)}  {str(min)}  {str(dollars < min)}")

    if dollars is not None and dollars < min:
      errors.append(f"dollars must be {format(min, '.2f')} or more")
    elif dollars is not None and dollars >= max:
      errors.append(f"dollars must be less than {format(max, '.2f')}")

  current_app.logger.info(f"{len(errors)}  {errors}")
  return (dollars, errors)

@bp.route("/btcpay", methods=("GET", "POST"))
@account_required
def btcpay_payment():
  errors = list()

  if current_app.config['BTCPAY_URL'] == "":
    flash("BTCPay is not enabled on this server")
    return redirect(url_for("console.account_balance"))
  elif 'BTCPAY_CLIENT' not in current_app.config:
    if not try_reconnnect_btcpay():
      flash("can't contact the BTCPay server right now")
      return redirect(url_for("console.account_balance"))

  if request.method == "POST":
    dollars, errors = validate_dollars(0.01, 1000.0)
    #current_app.logger.info(f"{len(errors)}  {errors}")

    if len(errors) == 0:
      try:
        invoice = current_app.config['BTCPAY_CLIENT'].create_invoice(dict(
          price=float(dollars), 
          currency="USD",
          itemDesc="Capsul Cloud Compute",
          transactionSpeed="high",
          redirectURL=f"{current_app.config['BASE_URL']}/console/account-balance",
          notificationURL=f"{current_app.config['BASE_URL']}/payment/btcpay/webhook"
        ))
      except:
        current_app.logger.error(f"An error occurred while attempting to reach BTCPay Server: {my_exec_info_message(sys.exc_info())}")
        flash("An error occurred while attempting to reach BTCPay Server.")
        return redirect(url_for("console.account_balance"))

      current_app.logger.info(f"created btcpay invoice: {invoice}")

      # print(invoice)

      current_app.logger.info(f"created btcpay invoice_id={invoice['id']} ( {session['account']}, ${dollars} )")

      get_model().create_payment_session("btcpay", invoice["id"], session["account"], dollars)

      return redirect(invoice["url"])

  for error in errors:
    flash(error)

  return render_template("btcpay.html")


def poll_btcpay_session(invoice_id):

  if 'BTCPAY_CLIENT' not in current_app.config:
    if not try_reconnnect_btcpay():
      return [503, "can't contact btcpay server"]

  invoice = None
  try:
    invoice = current_app.config['BTCPAY_CLIENT'].get_invoice(invoice_id)
  except:
    current_app.logger.error(f"""
      error was thrown when contacting btcpay server:
      {my_exec_info_message(sys.exc_info())}"""
    )
    return [503, "error was thrown when contacting btcpay server"]
    

  if invoice['currency'] != "USD":
    return [400, "invalid currency"]
  
  dollars = invoice['price']

  current_app.logger.info(f"poll_btcpay_session invoice_id={invoice_id}, status={invoice['status']} dollars={dollars}")

  if invoice['status'] == "paid" or invoice['status'] == "confirmed" or invoice['status'] == "complete":
    success_account = get_model().consume_payment_session("btcpay", invoice_id, dollars)
        
    if success_account:
      current_app.logger.info(f"{success_account} paid ${dollars} successfully (btcpay_invoice_id={invoice_id})")

  if invoice['status'] == "complete":
    resolved_invoice_email = get_model().btcpay_invoice_resolved(invoice_id, True)
    
    if resolved_invoice_email is not None:
      check_if_shortterm_flag_can_be_unset(resolved_invoice_email)

  elif invoice['status'] == "expired" or invoice['status'] == "invalid":
    get_model().btcpay_invoice_resolved(invoice_id, False)
    get_model().delete_payment_session("btcpay", invoice_id)
  
  return [200, "ok"]

def try_reconnnect_btcpay():
  try:
    response = requests.get(current_app.config['BTCPAY_URL'])
    if response.status_code == 200:
      current_app.config['BTCPAY_CLIENT'] = btcpay.Client(api_uri=current_app.config['BTCPAY_URL'], pem=current_app.config['BTCPAY_PRIVATE_KEY'])
      return True
    else:
      current_app.logger.warn(f"Can't reach BTCPAY_URL {current_app.config['BTCPAY_URL']}: Response status code: {response.status_code}. Capsul will work fine except cryptocurrency payments will not work.")
      return False
  except:
    current_app.logger.warn("unable to create btcpay client. Capsul will work fine except cryptocurrency payments will not work. The error was: " + my_exec_info_message(sys.exc_info()))
    return False


@bp.route("/btcpay/webhook", methods=("POST",))
def btcpay_webhook():
  
  current_app.logger.info(f"got btcpay webhook")

  # IMPORTANT! there is no signature or credential to authenticate the data sent into this webhook :facepalm:
  # its just a notification, thats all.
  request_data = json.loads(request.data)
  invoice_id = request_data['id']

  # so you better make sure to get the invoice data directly from the horses mouth! 
  result = poll_btcpay_session(invoice_id)

  return result[1], result[0]


# if the user has any shortterm vms (vms which were created at a time when they could not pay for that vm for 1 month)
# then it would be nice if those vms could be "promoted" to long-term if they pay up enough to cover costs for 1 month
def check_if_shortterm_flag_can_be_unset(email: str):
  vms = get_model().list_vms_for_account(email)
  payments = get_model().list_payments_for_account(email)
  balance = get_account_balance(vms, payments, datetime.utcnow() + timedelta(days=average_number_of_days_in_a_month))
  if balance > 0:
    get_model().clear_shortterm_flag(email)


@bp.route("/stripe", methods=("GET", "POST"))
@account_required
def stripe_payment():

  stripe_checkout_session_id=None
  errors = list()

  if request.method == "POST":
    dollars, errors = validate_dollars(0.5, 1000000)

    if len(errors) == 0:

      current_app.logger.info(f"creating stripe checkout session for {session['account']}, ${dollars}")

      checkout_session = stripe.checkout.Session.create(
        success_url=current_app.config['BASE_URL'] + "/payment/stripe/success?session_id={CHECKOUT_SESSION_ID}",
        cancel_url=current_app.config['BASE_URL'] + "/payment/stripe",
        payment_method_types=["card"],
        #customer_email=session["account"],
        line_items=[
          {
            "name": "Capsul Cloud Compute",
            "images": [current_app.config['BASE_URL']+"/static/capsul-product-image.png"],
            "quantity": 1,
            "currency": "usd",
            "amount": int(dollars*100)
          }
        ]
      )
      stripe_checkout_session_id = checkout_session['id']

      current_app.logger.info(f"stripe_checkout_session_id={stripe_checkout_session_id} ( {session['account']}, ${dollars} )")

      get_model().create_payment_session("stripe", stripe_checkout_session_id, session["account"], dollars)

      # We can't do this because stripe requires a bunch of server-authenticated data to be sent in the hash
      # of the URL. I briefly looked into reverse-engineering their proprietary javascript in order to try to figure out
      # how it works and gave up after I discovered that it would require multiple complex interactions with stripe's
      # servers, and it looked like they were trying to make what I was trying to do impossible. 

      # I never tried running the stripe proprietary javascript in a headless brower and passing the hash from the 
      # headless browser to the client, but I suspect it might not work anyway because they probably have thier tracking
      # cookie info in there somewhere, and if the cookie doesn't match they may refuse to display the page.

      #return redirect(f"https://checkout.stripe.com/pay/{stripe_checkout_session_id}")

      return redirect(f"/payment/stripe/{stripe_checkout_session_id}")

  for error in errors:
    flash(error)

  return render_template("stripe.html")

@bp.route("/stripe/<string:stripe_checkout_session_id>")
@account_required
def redirect_to_stripe(stripe_checkout_session_id):

  if stripe_checkout_session_id and not re.match(r"^[a-zA-Z0-9_=-]+$", stripe_checkout_session_id):
    stripe_checkout_session_id = '___________'

  response = make_response(render_template(
    "stripe.html",
    stripe_checkout_session_id=stripe_checkout_session_id,
    stripe_public_key=current_app.config["STRIPE_PUBLISHABLE_KEY"]
  ))

  response.headers['Content-Security-Policy'] = "default-src 'self' https://js.stripe.com"
  
  return response

@bp.route("/stripe/<string:stripe_checkout_session_id>/json")
@account_required
def stripe_checkout_session_json(stripe_checkout_session_id):

  if stripe_checkout_session_id and not re.match(r"^[a-zA-Z0-9_=-]+$", stripe_checkout_session_id):
    stripe_checkout_session_id = '___________'

  has_redirected_already = get_model().payment_session_redirect(session['account'], stripe_checkout_session_id)

  if has_redirected_already is None:
    abort(404, "Not Found")

  return jsonify(dict(hasRedirectedAlready=has_redirected_already))



def validate_stripe_checkout_session(stripe_checkout_session_id):
  checkout_session_completed_events = stripe.Event.list(
    type='checkout.session.completed',
    created={
      # Check for events created in the last half hour
      'gte': int(time.time() - (30 * 60)),
    },
  )

  for event in checkout_session_completed_events.auto_paging_iter():
    checkout_session = event['data']['object']

    if checkout_session and 'id' in checkout_session and checkout_session['id'] == stripe_checkout_session_id:
      cents = checkout_session['amount_total']
      dollars = decimal.Decimal(cents)/100

      #consume_payment_session deletes the checkout session row and inserts a payment row
      # its ok to call consume_payment_session more than once because it only takes an action if the session exists
      success_email = get_model().consume_payment_session("stripe", stripe_checkout_session_id, dollars)

      if success_email is not None:
        check_if_shortterm_flag_can_be_unset(success_email)

      if success_email:
        return dict(email=success_email, dollars=dollars)

  return None

@bp.route("/stripe/success", methods=("GET",))
def success():
  stripe_checkout_session_id = request.args.get('session_id')
  if not stripe_checkout_session_id:
    current_app.logger.info("/payment/stripe/success returned 400: missing required URL parameter session_id")
    abort(400, "missing required URL parameter session_id")
  else:
    for _ in range(0, 5):
      paid = validate_stripe_checkout_session(stripe_checkout_session_id)
      if paid:
        current_app.logger.info(f"{paid['email']} paid ${paid['dollars']} successfully (stripe_checkout_session_id={stripe_checkout_session_id})")
        
        return redirect(url_for("console.account_balance"))
      else:
        sleep(1)

  
  abort(400, "this checkout session is not paid yet")

# webhook is not needed 
# @bp.route("/webhook", methods=("POST",))
# def webhook():
#   request_data = json.loads(request.data)
#   signature = request.headers.get('stripe-signature')
#   try:
#     event = stripe.Webhook.construct_event(
#       payload=request_data, 
#       sig_header=signature, 
#       secret=current_app.config['STRIPE_WEBHOOK_SECRET']
#     )
#     if event['type'] == 'checkout.session.completed':
#       dollars = event['data']['object']['amount_total']
#       stripe_checkout_session_id = event['data']['object']['id']

#       #consume_payment_session deletes the checkout session row and inserts a payment row
#       # its ok to call consume_payment_session more than once because it only takes an action if the session exists
#       success_account = get_model().consume_payment_session("stripe", stripe_checkout_session_id, dollars)
#       if success_account:
#         print(f"{success_account} paid ${dollars} successfully (stripe_checkout_session_id={stripe_checkout_session_id})")
    
#     return jsonify({'status': 'success'})
#   except ValueError as e:
#     print("/payment/stripe/webhook returned 400: bad request", e)
#     abort(400, "bad request")
#   except stripe.error.SignatureVerificationError:
#     print("/payment/stripe/webhook returned 400: invalid signature")
#     abort(400, "invalid signature")