feat: add complete order endpoint

Author: drajk

src/pages/api/checkout.js

@@ -1,15 +1,17 @@
 import { PAYMENT_TYPE } from "../../core/constants";
-import { getById } from "../../services/quote";
-import initiateLatitudePurchase from "../../services/latitude/initiatePurchase";
+import * as quoteService from "../../services/quote";
+import * as latitudeService from "../../services/latitude";
 
 const handlePost = async (req, res) => {
   const { quoteId, paymentType } = req?.body || {};
-  const quote = getById(quoteId);
+  const quote = quoteService.getById(quoteId);
 
   switch (paymentType) {
     case PAYMENT_TYPE.LATITUDE_INTEREST_FREE:
-      const { result, redirectUrl } = await initiateLatitudePurchase(quote);
-      res.status(200).json({ result, redirectUrl })
+      const { result, redirectUrl } = await latitudeService.initiatePurchase(
+        quote
+      );
+      res.status(200).json({ result, redirectUrl });
       break;
 
     // Other payment methods here

src/pages/api/latitude/complete.js

@@ -0,0 +1,55 @@
+import * as quoteService from "../../../services/quote";
+import * as latitudeService from "../../../services/latitude";
+
+const handlePost = async (req, res) => {
+  const { merchantReference, transactionReference, gatewayReference } =
+    req?.body || {};
+
+  if (!merchantReference || !transactionReference || !gatewayReference) {
+    res.status(400).end("Missing required params");
+    break;
+  }
+
+  // verify whether quote exists in your DB
+  const quote = quoteService.getById(merchantReference);
+
+  if (!quote.id) {
+    res.status(400).end(`Quote ${merchantReference} not found`);
+    break;
+  }
+
+  const { result } = await latitudeService.verifyPurchase({
+    merchantReference,
+    transactionReference,
+    gatewayReference,
+  });
+
+  // mark order as paid when result = "completed"
+  if (result === "completed") {
+    const { orderId } = quoteService.markAsPaid({
+      quoteId: merchantReference,
+      transactionReference,
+      gatewayReference,
+    });
+
+    res.status(200).json({ orderId });
+    return;
+  }
+
+  // handle result = "failed" and other exceptions
+  res.status(400).end(`Could not complete quote ${merchantReference}`);
+};
+
+const handleDefault = (req, res) => {
+  const { method } = req;
+  res.setHeader("Allow", Object.keys(handlers));
+  res.status(405).end(`Method ${method} not allowed`);
+};
+
+const handlers = {
+  POST: handlePost,
+  default: handleDefault,
+};
+
+export default (req, res) =>
+  (handlers[req.method] || handlers.default)(req, res);

src/services/latitude/common.js

@@ -0,0 +1,18 @@
+export const MERCHANT_ID = process.env.LATITUDE_MERCHANT_ID;
+export const IS_PRODUCTION = process.env.IS_PRODUCTION;
+
+export const AXIOS_CONFIG = {
+  // axios auto-generates authorisation header with auth.username and auth.password
+  auth: {
+    username: MERCHANT_ID,
+    password: process.env.LATITUDE_MERCHANT_SECRET,
+  },
+  headers: {
+    "Content-Type": "application/json",
+  },
+};
+
+export const ENDPOINTS = {
+  PURCHASE: `${API_BASE_URL}/purchase`,
+  VERIFY_PURCHASE: `${API_BASE_URL}/purchase/verify`,
+};

src/services/latitude/index.js

@@ -0,0 +1,2 @@
+export * from "./initiatePurchase";
+export * from "./verifyPurchase";

src/services/latitude/initiatePurchase.js

@@ -2,36 +2,24 @@ import axios from "axios";
 
 import prepareRequest from "./prepareRequest";
 
-const API_BASE_URL = process.env.LATITUDE_API_BASE_URL;
-const MERCHANT_ID = process.env.LATITUDE_MERCHANT_ID;
-const MERCHANT_SECRET = process.env.LATITUDE_MERCHANT_SECRET;
+import { AXIOS_CONFIG, ENDPOINTS } from "./common";
+
+const ERROR_RESPONSE = {
+  result: "failed",
+  redirectUrl: "/error",
+};
 
 /**
  * Initiates request with Latitude Interest free
  * @param {object} quote
  */
-const initiatePurchase = async (quote) => {
+export const initiatePurchase = async (quote) => {
   try {
     const data = prepareRequest(quote);
-
-    const response = await axios.post(`${API_BASE_URL}/purchase`, data, {
-      // axios auto-generates authorisation header with auth.username and auth.password
-      auth: {
-        username: MERCHANT_ID,
-        password: MERCHANT_SECRET,
-      },
-      headers: {
-        "Content-Type": "application/json",
-      },
-    });
+    const response = await axios.post(ENDPOINTS.PURCHASE, data, AXIOS_CONFIG);
 
     return response?.data;
   } catch (err) {
-    return {
-      result: "failed",
-      redirectUrl: "/error",
-    };
+    return ERROR_RESPONSE;
   }
 };
-
-export default initiatePurchase;

src/services/latitude/prepareRequest.js

@@ -1,7 +1,6 @@
-const MERCHANT_ID = process.env.LATITUDE_MERCHANT_ID;
-const IS_PRODUCTION = process.env.IS_PRODUCTION;
+import { MERCHANT_ID, IS_PRODUCTION } from "./common";
 
-const prepareRequest = (quote) => ({
+export default (quote) => ({
   merchantId: MERCHANT_ID,
   merchantName: "example-store-javascript",
   isTest: !Boolean(IS_PRODUCTION),
@@ -52,8 +51,6 @@ const prepareRequest = (quote) => ({
   totalShippingAmount: quote.shipping.amount,
   totalTaxAmount: quote.tax.amount,
   totalDiscountAmount: quote.discount.amount,
-  platformType: "custom",
+  platformType: "direct",
   platformVersion: "0.0.1",
 });
-
-export default prepareRequest;

src/services/latitude/verifyPurchase.js

@@ -0,0 +1,36 @@
+import axios from "axios";
+import { AXIOS_CONFIG, ENDPOINTS } from "./common";
+
+const ERROR_RESPONSE = {
+  result: "failed",
+};
+
+/**
+ * Verifies purchase request with Latitude Interest free
+ * @param {string} merchantReference
+ * @param {string} transactionRefeference
+ * @param {string} gatewayReference
+ */
+export const verifyPurchase = async ({
+  merchantReference = "",
+  transactionRefeference = "",
+  gatewayReference = "",
+}) => {
+  try {
+    const data = {
+      merchantReference,
+      transactionRefeference,
+      gatewayReference,
+    };
+
+    const response = await axios.get(
+      ENDPOINTS.VERIFY_PURCHASE,
+      data,
+      AXIOS_CONFIG
+    );
+
+    return response?.data;
+  } catch (err) {
+    return ERROR_RESPONSE;
+  }
+};

src/services/quote/index.js

@@ -6,3 +6,23 @@ import mockQuote from "../../__mocks__/quote.json";
  * @param {string} quoteId
  */
 export const getById = (quoteId) => mockQuote;
+
+/**
+ * Currently returns a mock order id.
+ * Ideally this function is expected to
+ * - change status to "Paid" (or similar)
+ * - store transactionReference gatewayReference in DB for future reference
+ * @param {string} quoteId
+ * @param {string} transactionReference
+ * @param {string} gatewayReference
+ */
+export const markAsPaid = ({
+  quoteId,
+  transactionReference,
+  gatewayReference,
+}) => ({
+  orderId: 30440,
+  quoteId,
+  transactionReference,
+  gatewayReference,
+});