reactioncommerce · brent-hoover · Jan 24, 2023 · Nov 28, 2022
diff --git a/packages/api-plugin-carts/package.json b/packages/api-plugin-carts/package.json
@@ -31,6 +31,7 @@
     "@reactioncommerce/random": "^1.0.2",
     "@reactioncommerce/reaction-error": "^1.0.1",
     "accounting-js": "^1.1.1",
+    "graphql-subscriptions": "^2.0.0",
     "lodash": "^4.17.15",
     "simpl-schema": "^1.12.0"
   },

diff --git a/packages/api-plugin-carts/src/resolvers/Subscription/cartUpdated.js b/packages/api-plugin-carts/src/resolvers/Subscription/cartUpdated.js
@@ -0,0 +1,49 @@
+import { withFilter } from "graphql-subscriptions";
+import ReactionError from "@reactioncommerce/reaction-error";
+import hashToken from "@reactioncommerce/api-utils/hashToken.js";
+
+/**
+ * @summary Filters the subscription result
+ * @param {Object} payload - The subscription payload
+ * @param {Object} variables - The subscription variables
+ * @returns {Boolean} - Whether the subscription result should be sent to the client
+ */
+export function filter(payload, variables) {
+  const { cartUpdated: cart } = payload;
+  const { input: { cartId, accountId, cartToken } } = variables;
+
+  if (!cart) return false;
+  if (cart._id !== cartId) return false;
+  if (accountId) return cart.accountId === accountId;
+  return cart.anonymousAccessToken === hashToken(cartToken);
+}
+
+/**
+ * @summary Publishes the updated cart to the client
+ * @param {Object} _ unused
+ * @param {Object} args - The arguments passed to the subscription
+ * @param {Object} context - The application context
+ * @returns {Promise<Object>} the filtered subscription result
+ */
+async function cartUpdated(_, args, context) {
+  const { input: { cartId, accountId, cartToken } } = args;
+  const { collections: { Cart, Accounts }, userId } = context;
+
+  const selector = { _id: cartId };
+  if (accountId) {
+    const account = await Accounts.findOne({ _id: accountId, userId });
+    if (!account) throw new ReactionError("invalid-params", "Account id does not match user id");
+    selector.accountId = accountId;
+  } else {
+    selector.anonymousAccessToken = hashToken(cartToken);
+  }
+
+  const cart = await Cart.findOne(selector);
+  if (!cart) throw new ReactionError("not-found", "Cart not found");
+
+  return withFilter(() => context.pubSub.asyncIterator(["CART_UPDATED"]), filter)(_, args, context);
+}
+
+export default {
+  subscribe: cartUpdated
+};
diff --git a/packages/api-plugin-carts/src/resolvers/Subscription/cartUpdated.test.js b/packages/api-plugin-carts/src/resolvers/Subscription/cartUpdated.test.js
@@ -0,0 +1,121 @@
+import mockContext from "@reactioncommerce/api-utils/tests/mockContext.js";
+import { withFilter } from "graphql-subscriptions";
+import hashToken from "@reactioncommerce/api-utils/hashToken.js";
+import cartUpdated, { filter } from "./cartUpdated.js";
+
+jest.mock("@reactioncommerce/api-utils/hashToken.js", () => jest.fn().mockName("hashToken"));
+jest.mock("graphql-subscriptions", () => ({ withFilter: jest.fn() }));
+
+mockContext.pubSub = {
+  asyncIterator: jest.fn().mockName("pubSub.asyncIterator")
+};
+
+beforeEach(() => jest.resetAllMocks());
+
+test("filter returns false when payload does't contain cart", () => {
+  const payload = {};
+  const variables = { input: {} };
+  expect(filter(payload, variables)).toBe(false);
+});
+
+test("filter returns false when the input does't contain cardId", () => {
+  const payload = { cartUpdated: { _id: "cartId" } };
+  const variables = { input: { accountId: "accountId" } };
+  expect(filter(payload, variables)).toBe(false);
+});
+
+test("filter return true when provided correct cartId and accountId input", () => {
+  const payload = { cartUpdated: { _id: "cartId", accountId: "accountId" } };
+  const variables = { input: { cartId: "cartId", accountId: "accountId" } };
+  expect(filter(payload, variables)).toBe(true);
+});
+
+test("filter return false when provided incorrect cartId and accountId input", () => {
+  const payload = { cartUpdated: { _id: "cartId", accountId: "accountId" } };
+  const variables = { input: { cartId: "cartId", accountId: "incorrectAccountId" } };
+  expect(filter(payload, variables)).toBe(false);
+});
+
+test("filter return true when provided correct cartId and cartToken input", () => {
+  hashToken.mockReturnValueOnce("hashToken");
+  const payload = { cartUpdated: { _id: "cartId", anonymousAccessToken: "hashToken" } };
+  const variables = { input: { cartId: "cartId", cartToken: "token" } };
+  expect(filter(payload, variables)).toBe(true);
+});
+
+test("filter return false when provided incorrect cartId and cartToken input", () => {
+  hashToken.mockReturnValueOnce("incorrectHashToken");
+  const payload = { cartUpdated: { _id: "cartId", anonymousAccessToken: "hashToken" } };
+  const variables = { input: { cartId: "cartId", cartToken: "token" } };
+  expect(filter(payload, variables)).toBe(false);
+});
+
+test("cartUpdated throws invalid-params error when input is provided accountId but context is'nt contain userId", async () => {
+  const context = { ...mockContext };
+  const args = { input: { cartId: "cartId", accountId: "accountId" } };
+  context.userId = undefined;
+  context.collections.Accounts.findOne.mockReturnValueOnce(Promise.resolve(null));
+
+  try {
+    await cartUpdated.subscribe(null, args, context);
+  } catch (error) {
+    expect(error.error).toEqual("invalid-params");
+  }
+});
+
+test("cartUpdated find cart with accountId when input is provided accountId", async () => {
+  const mockFn = jest.fn();
+  // eslint-disable-next-line no-unused-vars
+  withFilter.mockImplementation((subscribe, _filterFn) => {
+    subscribe();
+    return mockFn;
+  });
+
+  const context = { ...mockContext };
+  const args = { input: { cartId: "cartId", accountId: "accountId" } };
+  context.userId = "userId";
+  context.collections.Accounts.findOne.mockReturnValueOnce(Promise.resolve({ _id: "accountId", userId: "userId" }));
+  context.collections.Cart.findOne.mockReturnValueOnce(Promise.resolve({ _id: "cartId", accountId: "accountId" }));
+
+  await cartUpdated.subscribe(null, args, context);
+  expect(context.collections.Cart.findOne).toHaveBeenCalledWith({ _id: "cartId", accountId: "accountId" });
+});
+
+test("cartUpdated find cart with anonymousAccessToken when input is provided cartToken", async () => {
+  const mockFn = jest.fn();
+  // eslint-disable-next-line no-unused-vars
+  withFilter.mockImplementation((subscribe, _filterFn) => {
+    subscribe();
+    return mockFn;
+  });
+  hashToken.mockReturnValueOnce("hashToken");
+
+  const context = { ...mockContext };
+  const args = { input: { cartId: "cartId", cartToken: "token" } };
+  context.userId = "userId";
+  context.collections.Cart.findOne.mockReturnValueOnce(Promise.resolve({ _id: "cartId", anonymousAccessToken: "hashToken" }));
+
+  await cartUpdated.subscribe(null, args, context);
+  expect(context.collections.Cart.findOne).toHaveBeenCalledWith({ _id: "cartId", anonymousAccessToken: "hashToken" });
+});
+
+test("cartUpdated should throws not-found error when cart is not found", async () => {
+  const mockFn = jest.fn();
+  // eslint-disable-next-line no-unused-vars
+  withFilter.mockImplementation((subscribe, _filterFn) => {
+    subscribe();
+    return mockFn;
+  });
+
+  const context = { ...mockContext };
+  const args = { input: { cartId: "cartId", accountId: "accountId" } };
+  context.userId = "userId";
+  context.collections.Accounts.findOne.mockReturnValueOnce(Promise.resolve({ _id: "accountId", userId: "userId" }));
+  context.collections.Cart.findOne.mockReturnValueOnce(Promise.resolve(null));
+
+  try {
+    await cartUpdated.subscribe(null, args, context);
+  } catch (error) {
+    expect(error.error).toEqual("not-found");
+  }
+});
diff --git a/packages/api-plugin-carts/src/resolvers/Subscription/index.js b/packages/api-plugin-carts/src/resolvers/Subscription/index.js
@@ -0,0 +1,3 @@
+import cartUpdated from "./cartUpdated.js";
+
+export default { cartUpdated };
diff --git a/packages/api-plugin-carts/src/resolvers/index.js b/packages/api-plugin-carts/src/resolvers/index.js
@@ -3,6 +3,7 @@ import CartItem from "./CartItem/index.js";
 import FulfillmentGroup from "./FulfillmentGroup/index.js";
 import Mutation from "./Mutation/index.js";
 import Query from "./Query/index.js";
+import Subscription from "./Subscription/index.js";
 
 /**
  * Cart related GraphQL resolvers
@@ -14,6 +15,7 @@ export default {
   CartItem,
   FulfillmentGroup,
   Mutation,
+  Subscription,
   PaymentMethodData: {
     __resolveType(obj) {
       return obj.gqlType;

diff --git a/packages/api-plugin-carts/src/schemas/cart.graphql b/packages/api-plugin-carts/src/schemas/cart.graphql
@@ -419,6 +419,17 @@ input SetEmailOnAnonymousCartInput {
   email: String!
 }
 
+input CartUpdatedInput {
+  "The cart ID"
+  cartId: ID!,
+
+  "The cart account ID"
+  accountId: ID
+
+  "The cart anonymous token"
+  cartToken: String
+}
+
 ####################
 # Payloads
 # These types are used as return values for mutation calls
@@ -595,3 +606,13 @@ extend type Mutation {
     input: UpdateCartItemsQuantityInput!
   ): UpdateCartItemsQuantityPayload!
 }
+
+####################
+ # Subscriptions
+ ####################
+extend type Subscription {
+  "Subscribe to changes to cart"
+  cartUpdated(
+    input: CartUpdatedInput!
+  ): Cart!
+}
diff --git a/packages/api-plugin-carts/src/startup.js b/packages/api-plugin-carts/src/startup.js
@@ -1,5 +1,6 @@
 import Logger from "@reactioncommerce/logger";
 import updateCartItemsForVariantChanges from "./util/updateCartItemsForVariantChanges.js";
+import publishCartUpdatedEvent from "./util/publishCartUpdatedEvent.js";
 import { MAX_CART_COUNT as SAVE_MANY_CARTS_LIMIT } from "./mutations/saveManyCarts.js";
 
 const logCtx = { name: "cart", file: "startup" };
@@ -98,6 +99,10 @@ export default async function cartStartup(context) {
   const { appEvents, collections } = context;
   const { Cart } = collections;
 
+  appEvents.on("afterCartUpdate", async ({ cart: updatedCart, publishUpdatedEvent = true }) => {
+    publishCartUpdatedEvent(context, updatedCart, { publishUpdatedEvent });
+  });
+
   // When an order is created, delete the source cart
   appEvents.on("afterOrderCreate", async ({ order }) => {
     const { cartId } = order;

diff --git a/packages/api-plugin-carts/src/util/publishCartUpdatedEvent.js b/packages/api-plugin-carts/src/util/publishCartUpdatedEvent.js
@@ -0,0 +1,11 @@
+/**
+ * @summary Publishes a cart updated event
+ * @param {Object} context - The application context
+ * @param {Object} cart - The cart that was updated
+ * @param {Boolean} params.publishUpdatedEvent - Whether to prevent publishing the event
+ * @returns {void} - undefined
+ */
+export default function publishCartUpdatedEvent(context, cart, { publishUpdatedEvent = undefined }) {
+  if (!context.app.hasSubscriptionsEnabled || !publishUpdatedEvent) return;
+  context.pubSub.publish("CART_UPDATED", { cartUpdated: cart });
+}
diff --git a/packages/api-plugin-carts/src/util/publishCartUpdatedEvent.test.js b/packages/api-plugin-carts/src/util/publishCartUpdatedEvent.test.js
@@ -0,0 +1,29 @@
+import publishCartUpdatedEvent from "./publishCartUpdatedEvent.js";
+
+const context = {
+  app: {
+    hasSubscriptionsEnabled: true
+  },
+  pubSub: {
+    publish: jest.fn()
+  }
+};
+
+test("shouldn't publish event when subscription is disabled", async () => {
+  context.app.hasSubscriptionsEnabled = false;
+  publishCartUpdatedEvent(context, {}, { publishUpdatedEvent: true });
+  expect(context.pubSub.publish).not.toHaveBeenCalled();
+});
+
+test("shouldn't publish event when publishUpdatedEvent arg is undefined", async () => {
+  context.app.hasSubscriptionsEnabled = true;
+  publishCartUpdatedEvent(context, {}, { publishUpdatedEvent: undefined });
+  expect(context.pubSub.publish).not.toHaveBeenCalled();
+});
+
+test("should publish cart updated event", async () => {
+  context.app.hasSubscriptionsEnabled = true;
+  const cart = { _id: "cartId" };
+  publishCartUpdatedEvent(context, cart, { publishUpdatedEvent: true });
+  expect(context.pubSub.publish).toHaveBeenCalledWith("CART_UPDATED", { cartUpdated: cart });
+});
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,3 @@
		import cartUpdated from "./cartUpdated.js";

		export default { cartUpdated };