Subscriptions using Stripe (#375)

* Interim checkin for subscriptions using Stripe

* test stripe subscriptions

metabrainz/model/payment.py

@@ -300,19 +300,30 @@ def _extract_paypal_ipn_options(form: dict) -> dict:
         return options
 
     @classmethod
-    def log_stripe_charge(cls, session):
+    def log_subscription_charge(cls, invoice):
+        """ Log successful Stripe charges for a recurring payment/donation """
+        charge = stripe.Charge.retrieve(invoice["charge"], expand=["balance_transaction"])
+        metadata = invoice["lines"]["data"][0]["metadata"]
+        return cls._log_stripe_charge(charge, metadata)
+
+    @classmethod
+    def log_one_time_charge(cls, session):
+        """ Log successful Stripe charge for one time payment/donation """
+        payment_intent = stripe.PaymentIntent.retrieve(session["payment_intent"],
+                                                       expand=["charges.data.balance_transaction"])
+        charge = payment_intent["charges"]["data"][0]
+        metadata = payment_intent["metadata"]
+        return cls._log_stripe_charge(charge, metadata)
+
+    @classmethod
+    def _log_stripe_charge(cls, charge, metadata):
         """Log successful Stripe charge.
 
         Args:
             session: The charge object from Stripe. More information about it is
                 available at https://stripe.com/docs/api/python#charge_object.
         """
         current_app.logger.debug("Processing Stripe charge...")
-        metadata = session["metadata"]
-
-        payment_intent = stripe.PaymentIntent.retrieve(session["payment_intent"],
-                                                       expand=["charges.data.balance_transaction"])
-        charge = payment_intent["charges"]["data"][0]
 
         # Transaction already exists in the database, do not insert again
         if db.session.query(exists().where(Payment.transaction_id == charge["id"])).scalar():
@@ -324,15 +335,15 @@ def log_stripe_charge(cls, session):
         transaction = charge["balance_transaction"]
         currency = transaction["currency"].lower()
         if currency not in SUPPORTED_CURRENCIES:
-            current_app.logger.warning("Unsupported currency: ", session["currency"])
+            current_app.logger.warning("Unsupported currency: ", transaction["currency"])
             return
 
         new_donation = cls(
             first_name=details["name"],
             last_name="",
             amount=transaction["net"] / 100,  # cents should be converted
             fee=transaction["fee"] / 100,  # cents should be converted
-            currency=currency,
+            currency="usd",
             transaction_id=charge["id"],
             payment_method=PAYMENT_METHOD_STRIPE,
             is_donation=metadata["is_donation"],

metabrainz/payments/stripe/views.py

@@ -22,45 +22,62 @@ def pay():
     if not form.validate():
         return redirect(url_for("payments.error", is_donation=is_donation))
 
+    is_recurring = form.recurring.data
+
     charge_metadata = {
         "is_donation": is_donation,
     }
-    if is_donation:
-        # Using DonationForm
+    if is_donation:  # Using DonationForm
         charge_metadata["editor"] = form.editor.data
         charge_metadata["anonymous"] = form.anonymous.data
         charge_metadata["can_contact"] = form.can_contact.data
         description = "Donation to the MetaBrainz Foundation"
-    else:
-        # Using PaymentForm
+    else:  # Using PaymentForm
         charge_metadata["invoice_number"] = form.invoice_number.data
-        description = f"Payment to the MetaBrainz Foundation for Invoice {form.invoice_number.data}"
+        # Add invoice number to description only for non-recurring payments
+        if is_recurring:
+            description = "Payment to the MetaBrainz Foundation"
+        else:
+            description = f"Payment to the MetaBrainz Foundation for Invoice {form.invoice_number.data}"
 
-    try:
-        session = stripe.checkout.Session.create(
-            billing_address_collection="required",
-            line_items=[{
+    session_config = {
+        "billing_address_collection": "required",
+        "line_items": [
+            {
                 "price_data": {
-                    "unit_amount": int(form.amount.data * 100), # amount in cents
+                    "unit_amount": int(form.amount.data * 100),  # amount in cents
                     "currency": form.currency.data,
                     "product_data": {
                         "name": "Support the MetaBrainz Foundation",
                         "description": description
                     }
                 },
                 "quantity": 1
-            }],
-            payment_intent_data={
-                "description": description
-            },
-            payment_method_types=["card"],
-            mode="payment",
-            submit_type="donate" if is_donation else "pay",
-            # stripe wants absolute urls so url_for doesn't suffice
-            success_url=f'{current_app.config["SERVER_BASE_URL"]}/payment/complete?is_donation={is_donation}',
-            cancel_url=f'{current_app.config["SERVER_BASE_URL"]}/payment/cancelled?is_donation={is_donation}',
-            metadata=charge_metadata
-        )
+            }
+        ],
+        "payment_method_types": ["card"],
+        "mode": "subscription",
+        # stripe wants absolute urls so url_for doesn't suffice
+        "success_url": f'{current_app.config["SERVER_BASE_URL"]}/payment/complete?is_donation={is_donation}',
+        "cancel_url": f'{current_app.config["SERVER_BASE_URL"]}/payment/cancelled?is_donation={is_donation}',
+    }
+
+    if is_recurring:
+        session_config["mode"] = "subscription"
+        # configure monthly subscription
+        session_config["line_items"][0]["price_data"]["recurring"] = {"interval": "month"}
+        session_config["subscription_data"] = {"metadata": charge_metadata}
+    else:
+        session_config["mode"] = "payment"
+        # submit_type and payment_intent_data are only allowed in payment mode
+        session_config["submit_type"] = "donate" if is_donation else "pay"
+        session_config["payment_intent_data"] = {
+            "description": description,
+            "metadata": charge_metadata
+        }
+
+    try:
+        session = stripe.checkout.Session.create(**session_config)
         return redirect(session.url, code=303)
     except Exception as e:
         current_app.logger.error(e, exc_info=True)
@@ -82,7 +99,14 @@ def webhook():
         current_app.logger.error("Stripe signature error, possibly fake event", exc_info=True)
         return jsonify({"error": "invalid signature"}), 400
 
+    # for one time payments, mode is payment, and we use the checkout.session.completed event to log charges
+    # other option is mode = subscription i.e. recurring payments, for which payment_intent data is unavailable
+    # in this webhook. hence, we use invoice.paid event instead which contains it.
     if event["type"] == "checkout.session.completed":
-        Payment.log_stripe_charge(event["data"]["object"])
+        session = event["data"]["object"]
+        if session["mode"] == "payment":
+            Payment.log_one_time_charge(session)
+    elif event["type"] == "invoice.paid":
+        Payment.log_subscription_charge(event["data"]["object"])
 
     return jsonify({"status": "ok"})

metabrainz/templates/payments/donate.html

@@ -192,9 +192,8 @@ <h3>GitHub</h3>
         // This function disables or enables payment buttons depending on what
         // features they support.
 
-        // We don't support recurring payments via Stripe. Payments in EUR are
-        // also not supported currently.
-        if ($('#recurring-flag').is(":checked") || selectedCurrency === CURRENCY.Euro) {
+        // We don't support payments in EUR via Stripe currently.
+        if (selectedCurrency === CURRENCY.Euro) {
           buttons.stripe.attr('disabled', 'disabled');
         } else {
           buttons.stripe.removeAttr('disabled');
@@ -234,13 +233,6 @@ <h3>GitHub</h3>
         updateButtonState();
       });
 
-      /////////////
-      // RECURRENCE
-      /////////////
-      $('#recurring-flag').change(function() {
-        updateButtonState();
-      });
-
       ///////////////
       // EDITOR INPUT
       ///////////////