Updated offer_id matching logic to use stripe_coupon_id instead of metadata (#390)

refs https://github.com/TryGhost/Team/issues/1519

- Removed offer metadata again from offer (added in one of the previous commits)
- Added `getByStripeCouponId` method in offer repository (required to find an offer based on the stripe_coupon_id)
- Match discounts from Stripe based on the stripe_coupon_id instead of metadata

ghost/members-api/lib/repositories/member.js

@@ -702,14 +702,16 @@ module.exports = class MemberRepository {
             logging.error(e);
         }
 
-        let offerId = subscription.discount && (subscription.discount.coupon.metadata.offer || subscription.metadata.offer) ? (subscription.discount.coupon.metadata.offer ? subscription.discount.coupon.metadata.offer : subscription.metadata.offer) : null;
+        let stripeCouponId = subscription.discount && subscription.discount.coupon ? subscription.discount.coupon.id : null;
+        let offerId = null;
 
-        if (offerId) {
-            // Validate the offer id from the metadata
-            const offer = await this._offerRepository.getById(offerId, {transacting: options.transacting});
-            if (!offer) {
-                logging.error(`Received an invalid offer id (${offerId}) in the metadata of a subscription - ${subscription.id}.`);
-                offerId = null;
+        if (stripeCouponId) {
+            // Get the offer from our database
+            const offer = await this._offerRepository.getByStripeCouponId(stripeCouponId, {transacting: options.transacting});
+            if (offer) {
+                offerId = offer.id;
+            } else {
+                logging.error(`Received an unknown stripe coupon id (${stripeCouponId}) for subscription - ${subscription.id}.`);
             }
         }
 
@@ -739,8 +741,6 @@ module.exports = class MemberRepository {
                 canceled: subscription.cancel_at_period_end,
                 discount: subscription.discount
             }),
-            // We try to use the offer_id that was stored in Stripe coupon and fallback to the one stored in the subscription
-            // This allows us to catch the offer_id from discounts (created by Ghost) that were applied via the Stripe dashboard
             offer_id: offerId
         };
 

ghost/offers/lib/application/OfferRepository.js

@@ -141,6 +141,24 @@ class OfferRepository {
         return this.mapToOffer(model, options);
     }
 
+    /**
+     * @param {string} id stripe_coupon_id
+     * @param {BaseOptions} [options]
+     * @returns {Promise<Offer>}
+     */
+    async getByStripeCouponId(id, options) {
+        const model = await this.OfferModel.findOne({stripe_coupon_id: id}, {
+            ...options,
+            withRelated: ['product']
+        });
+
+        if (!model) {
+            return null;
+        }
+
+        return this.mapToOffer(model, options);
+    }
+
     /**
      * @param {ListOptions} options
      * @returns {Promise<Offer[]>}

ghost/payments/lib/payments.js

@@ -48,11 +48,7 @@ class PaymentsService {
         /** @type {import('stripe').Stripe.CouponCreateParams} */
         const couponData = {
             name: offer.name,
-            duration: offer.duration,
-            // Note that the metadata is not present for older coupons
-            metadata: {
-                offer: offer.id
-            }
+            duration: offer.duration
         };
 
         if (offer.duration === 'repeating') {