feat(payment-stripe): add support for custom payment amounts (PWYW) (#209)

Author: ZynovII

microservices/authorization/migrations/permissions/list/models/payment-stripe.json

@@ -63,7 +63,15 @@
           "admin": "allow"
         }
       },
-      "product": "payment-stripe.Product"
+      "product": "payment-stripe.Product",
+      "metadata": {
+        "in": {
+          "admin": "allow"
+        },
+        "out": {
+          "admin": "allow"
+        }
+      }
     },
     "createdAt": "2023-05-26T13:01:39.186Z"
   },
@@ -306,7 +314,15 @@
         }
       },
       "customer": "payment-stripe.Customer",
-      "product": "payment-stripe.Product"
+      "product": "payment-stripe.Product",
+      "customAmount": {
+        "in": {
+          "admin": "allow"
+        },
+        "out": {
+          "user": "allow"
+        }
+      }
     },
     "createdAt": "2023-05-26T13:01:39.186Z"
   },

microservices/payment-stripe/migrations/1753535753000-add-custom-amount.ts

@@ -0,0 +1,19 @@
+import { MigrationInterface, QueryRunner } from 'typeorm';
+
+export default class AddCustomAmount1753535753000 implements MigrationInterface {
+  name = 'AddCustomAmount1753535753000';
+
+  public async up(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(`
+      ALTER TABLE "transaction"
+      ADD COLUMN "customAmount" integer DEFAULT null
+    `);
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(`
+      ALTER TABLE "transaction"
+      DROP COLUMN "customAmount"
+    `);
+  }
+}

microservices/payment-stripe/src/entities/transaction.ts

@@ -215,6 +215,15 @@ class Transaction {
   @IsNumber()
   amount: number;
 
+  @JSONSchema({
+    description: 'Custom amount paid by user for PWYW transactions (in cents)',
+  })
+  @Column({ type: 'int', default: null })
+  @IsUndefinable()
+  @IsNullable()
+  @IsNumber()
+  customAmount: number | null;
+
   @JSONSchema({
     description: `Sales tax or other, that should be paid to the government by tax collector. Tax included in the
       payment intent amount and storing as collected fees amount.`,

microservices/payment-stripe/src/methods/price/create.ts

@@ -1,6 +1,6 @@
 import { Endpoint } from '@lomray/microservice-helpers';
 import { Type } from 'class-transformer';
-import { IsNumber, IsObject, IsString } from 'class-validator';
+import { IsNumber, IsObject, IsString, IsOptional } from 'class-validator';
 import Price from '@entities/price';
 import Stripe from '@services/payment-gateway/stripe';
 
@@ -16,6 +16,10 @@ class PriceCreateInput {
 
   @IsNumber()
   unitAmount: number;
+
+  @IsObject()
+  @IsOptional()
+  metadata?: Record<string, string>;
 }
 
 class PriceCreateOutput {

microservices/payment-stripe/src/methods/stripe/create-checkout.ts

@@ -1,5 +1,5 @@
 import { Endpoint, IsNullable, IsUndefinable } from '@lomray/microservice-helpers';
-import { IsBoolean, IsString, Length } from 'class-validator';
+import { IsBoolean, IsNumber, IsString, Length } from 'class-validator';
 import Stripe from '@services/payment-gateway/stripe';
 
 class CreateCheckoutInput {
@@ -19,6 +19,10 @@ class CreateCheckoutInput {
   @IsBoolean()
   @IsUndefinable()
   isAllowPromoCode?: boolean;
+
+  @IsNumber()
+  @IsUndefinable()
+  customAmount?: number;
 }
 
 class CreateCheckoutOutput {
@@ -36,7 +40,7 @@ const createCheckout = Endpoint.custom(
     output: CreateCheckoutOutput,
     description: 'Setup intent and return client secret key',
   }),
-  async ({ priceId, successUrl, cancelUrl, userId, isAllowPromoCode }) => {
+  async ({ priceId, successUrl, cancelUrl, userId, isAllowPromoCode, customAmount }) => {
     const service = await Stripe.init();
 
     return {
@@ -46,6 +50,7 @@ const createCheckout = Endpoint.custom(
         successUrl,
         cancelUrl,
         isAllowPromoCode,
+        customAmount,
       }),
     };
   },

microservices/payment-stripe/src/services/payment-gateway/abstract.ts

@@ -41,6 +41,7 @@ export interface IPriceParams {
   userId: string;
   currency: string;
   unitAmount: number;
+  metadata?: Record<string, string>;
 }
 
 export interface ITransactionParams {
@@ -56,6 +57,7 @@ export interface ITransactionParams {
   tax?: number;
   fee?: number;
   params?: ITransactionEntityParams;
+  customAmount?: number;
 }
 
 export interface IProductParams {

microservices/payment-stripe/src/services/payment-gateway/stripe.ts

@@ -99,6 +99,7 @@ interface ICheckoutParams {
   successUrl: string;
   cancelUrl: string;
   isAllowPromoCode?: boolean;
+  customAmount?: number;
 }
 
 interface ICheckoutEvent {
@@ -369,16 +370,17 @@ class Stripe extends Abstract {
   }
 
   /**
-   * Create Price entity
+   * Create new price
    */
   public async createPrice(params: IPriceParams): Promise<Price> {
-    const { currency, unitAmount, productId, userId } = params;
+    const { currency, unitAmount, productId, userId, metadata } = params;
 
     const { id }: StripeSdk.Price = await this.sdk.prices.create({
       currency,
       product: productId,
       // eslint-disable-next-line camelcase
       unit_amount: unitAmount,
+      ...(metadata ? { metadata } : {}),
     });
 
     return super.createPrice(
@@ -396,7 +398,7 @@ class Stripe extends Abstract {
    * Create checkout session and return url to redirect user for payment
    */
   public async createCheckout(params: ICheckoutParams): Promise<string | null> {
-    const { priceId, userId, successUrl, cancelUrl, isAllowPromoCode } = params;
+    const { priceId, userId, successUrl, cancelUrl, isAllowPromoCode, customAmount } = params;
 
     const { customerId } = await super.getCustomer(userId);
     const price = await this.priceRepository.findOne({ priceId }, { relations: ['product'] });
@@ -408,29 +410,48 @@ class Stripe extends Abstract {
     }
 
     /* eslint-disable camelcase */
-    const { id, url } = await this.sdk.checkout.sessions.create({
-      line_items: [
-        {
-          price: priceId,
-          quantity: 1,
-        },
-      ],
+    const sessionParams: StripeSdk.Checkout.SessionCreateParams = {
       mode: 'payment',
       customer: customerId,
       success_url: successUrl,
       cancel_url: cancelUrl,
-      allow_promotion_codes: isAllowPromoCode,
-    });
+      allow_promotion_codes: isAllowPromoCode && !customAmount, // No promo codes for PWYW
+    };
+
+    if (customAmount) {
+      // PWYW mode - create custom line item with user-defined amount
+      sessionParams.line_items = [
+        {
+          price_data: {
+            currency: 'usd',
+            product: price.productId,
+            unit_amount: customAmount * 100, // Convert to cents
+          },
+          quantity: 1,
+        },
+      ];
+    } else {
+      // Fixed price mode
+      sessionParams.line_items = [
+        {
+          price: priceId,
+          quantity: 1,
+        },
+      ];
+    }
+
+    const { id, url } = await this.sdk.checkout.sessions.create(sessionParams);
     /* eslint-enable camelcase */
 
     await this.createTransaction(
       {
         type: TransactionType.CREDIT,
-        amount: price.unitAmount,
+        amount: customAmount ? customAmount * 100 : price.unitAmount, // Store in cents
         userId,
         productId: price.productId,
         entityId: price.product.entityId,
         status: TransactionStatus.INITIAL,
+        customAmount: customAmount ? customAmount * 100 : undefined, // Store custom amount in cents
       },
       id,
     );