Extract to business logic layer

Author: goldbergyoni

.DS_Store

@@ -0,0 +1,70 @@
+const util = require('util');
+const axios = require('axios');
+const mailer = require('../libraries/mailer');
+const axiosRetry = require('axios-retry');
+const OrderRepository = require('../data-access/order-repository');
+const { AppError } = require('../error-handling');
+const MessageQueueClient = require('../libraries/message-queue-client');
+
+const axiosHTTPClient = axios.create();
+axiosRetry(axiosHTTPClient, { retries: 3 });
+
+module.exports.addOrder = async function (newOrder) {
+  // validation
+  if (!newOrder.productId) {
+    throw new AppError('invalid-order', `No product-id specified`, 400);
+  }
+
+  // verify user existence by calling external Microservice
+  const userWhoOrdered = await getUserFromUsersService(newOrder.userId);
+  
+  if (!userWhoOrdered) {
+    throw new AppError(
+      'user-doesnt-exist',
+      `The user ${newOrder.userId} doesnt exist`,
+      404
+    );
+  }
+
+  // save to DB (Caution: simplistic code without layers and validation)
+  const DBResponse = await new OrderRepository().addOrder(newOrder);
+
+  if (process.env.SEND_MAILS === 'true') {
+    await mailer.send(
+      'New order was placed',
+      `user ${DBResponse.userId} ordered ${DBResponse.productId}`,
+      'admin@app.com'
+    );
+  }
+
+  // We should notify others that a new order was added - Let's put a message in a queue
+  await new MessageQueueClient().sendMessage('new-order', newOrder);
+
+  return DBResponse;
+};
+
+async function getUserFromUsersService(userId) {
+  try {
+    const getUserResponse = await axiosHTTPClient.get(
+      `http://localhost/user/${userId}`,
+      {
+        timeout: 2000,
+        validateStatus: (status) => {
+          return status < 500;
+        },
+      }
+    );
+    console.log(getUserResponse.data);
+    return getUserResponse.data;
+  } catch (error) {
+    if (error?.code === 'ECONNABORTED') {
+      throw new AppError(
+        'user-verification-failed',
+        `Request to user service failed so user cant be verified`,
+        503
+      );
+    }
+
+    throw error;
+  }
+}

example-application/.DS_Store

@@ -39,6 +39,7 @@ module.exports = class OrderRepository {
 
   async getOrderById(id) {
     return await orderModel.findOne({ where: { id } });
+
   }
 
   async addOrder(orderDetails) {

example-application/business-logic/order-service.js

@@ -1,19 +1,12 @@
 const express = require('express');
 const util = require('util');
 const bodyParser = require('body-parser');
-const axios = require('axios');
-const axiosRetry = require('axios-retry');
-const mailer = require('../libraries/mailer');
 const OrderRepository = require('../data-access/order-repository');
 const errorHandler = require('../error-handling').errorHandler;
-const { AppError } = require('../error-handling');
-const MessageQueueClient = require('../libraries/message-queue-client');
+const orderService = require('../business-logic/order-service');
 
 let connection;
 
-const client = axios.create();
-axiosRetry(client, { retries: 3 });
-
 const initializeWebServer = (customMiddleware) => {
   return new Promise((resolve, reject) => {
     // A typical Express setup
@@ -53,51 +46,8 @@ const defineRoutes = (expressApp) => {
       console.log(
         `Order API was called to add new Order ${util.inspect(req.body)}`
       );
-
-      // validation
-      if (!req.body.productId) {
-        res.status(400).end();
-
-        return;
-      }
-
-      // verify user existence by calling external Microservice
-      try {
-        await getUserFromUsersService(req.body.userId);
-      } catch (error) {
-        const { response } = error;
-
-        if (response && response.status === 404) {
-          res.status(404).end();
-          return;
-        }
-
-        if (error?.code === 'ECONNABORTED') {
-          throw new AppError(
-            'user-doesnt-exist',
-            `The user ${req.body.userId} doesnt exist`,
-            503
-          );
-        }
-
-        throw error;
-      }
-
-      // save to DB (Caution: simplistic code without layers and validation)
-      const DBResponse = await new OrderRepository().addOrder(req.body);
-
-      if (process.env.SEND_MAILS === 'true') {
-        await mailer.send(
-          'New order was placed',
-          `user ${DBResponse.userId} ordered ${DBResponse.productId}`,
-          'admin@app.com'
-        );
-      }
-
-      // We should notify others that a new order was added - Let's put a message in a queue
-      new MessageQueueClient().sendMessage('new-order', req.body);
-
-      res.json(DBResponse);
+      const addOrderResponse = await orderService.addOrder(req.body);
+      return res.json(addOrderResponse);
     } catch (error) {
       next(error);
     }
@@ -116,6 +66,8 @@ const defineRoutes = (expressApp) => {
     res.json(response);
   });
 
+  // delete order by id
+
   router.delete('/:id', async (req, res, next) => {
     console.log(`Order API was called to delete order ${req.params.id}`);
     await new OrderRepository().deleteOrder(req.params.id);
@@ -144,12 +96,6 @@ process.on('unhandledRejection', (reason) => {
   errorHandler.handleError(reason);
 });
 
-async function getUserFromUsersService(userId) {
-  return await client.get(`http://localhost/user/${userId}`, {
-    timeout: 2000,
-  });
-}
-
 module.exports = {
   initializeWebServer,
   stopWebServer,

example-application/data-access/.DS_Store

@@ -86,6 +86,10 @@
           "404": {
             "description": "User Not Found",
             "content": {}
+          },
+          "500": {
+            "description": "Unkonwn error occured",
+            "content": {}
           }
         }
       }

example-application/data-access/order-repository.js

@@ -1,5 +1,5 @@
 const { initializeWebServer } = require('./entry-points/api');
-const {MessageQueueStarter} = require('./entry-points/message-queue-starter');
+const { MessageQueueStarter } = require('./entry-points/message-queue-starter');
 
 async function start() {
   await initializeWebServer();

example-application/entry-points/api.js

@@ -208,10 +208,7 @@ describe('/api', () => {
 
     test('When the user does not exist, return 404 response', async () => {
       //Arrange
-      nock('http://localhost/user/').get(`/7`).reply(404, {
-        message: 'User does not exist',
-        code: 'nonExisting',
-      });
+      nock('http://localhost/user/').get(`/7`).reply(404, null);
       const orderToAdd = {
         userId: 7,
         productId: 2,

example-application/index.js

@@ -0,0 +1 @@
+Subproject commit 6e7a8d277f34184e7dc24aa24698769c3ccdbb82