chore: working on chapter 13

Author: lmammino

09-behavioral-design-patterns/17-command-s3-put-object/index.js

@@ -5,7 +5,6 @@ import { PutObjectCommand, S3Client } from '@aws-sdk/client-s3' // v3.750.0
 const [bucketName, filePath] = process.argv.slice(2)
 
 if (!(bucketName && filePath)) {
-  // biome-ignore lint/nursery/noSecrets: not a secret
   console.error('Usage: node index.js <bucketName> <filePath>')
   process.exit(1)
 }

10-testing/16-integration-test-http/booking.js

@@ -7,7 +7,6 @@ export async function reserveSeat(db, eventId, userId) {
   }
 
   const existing = await db.query(
-    // biome-ignore lint/nursery/noSecrets: <explanation>
     'SELECT COUNT(*) AS count FROM reservations WHERE eventId = ?',
     [eventId]
   )

13-messaging-and-integration-patterns/04-pubsub-amqp/.gitignore

@@ -0,0 +1 @@
+msgHistory/

13-messaging-and-integration-patterns/04-pubsub-amqp/README.md

@@ -0,0 +1,63 @@
+# 04-pubsub-amqp
+
+This sample demonstrates how to integrate a chat application and a microservice
+using AMQP
+
+## Dependencies
+
+As pre-requisite to this sample, you first need to
+[install RabbitMQ](http://www.rabbitmq.com/download.html)
+
+If you have docker installed, you can run an ephemeral instance of RabbitMQ with
+the following command:
+
+```bash
+docker run -it -p 5672:5672 --hostname my-rabbit rabbitmq:3
+```
+
+This example requires you to install some third-party dependencies from npm.
+
+If you have `pnpm` installed, you can do that with:
+
+```bash
+pnpm install
+```
+
+Alternatively, if you prefer to use another package manager, make sure to delete
+the `pnpm-lock.yaml` file before using it.
+
+If you want to use `npm`, you can run:
+
+```bash
+npm install
+```
+
+If you want to use `yarn`, you can run:
+
+```bash
+yarn install
+```
+
+## Run
+
+To run the various components, run in different terminals the following
+commands:
+
+```bash
+node index.js 8080 # runs a version of the chat application on port 8080
+node index.js 8081 # runs a version of the chat application on port 8081
+node historySvc.js # runs the history service
+```
+
+Then you can access the chat application by opening your browser and navigating
+to:
+
+```
+http://localhost:8080
+```
+
+or
+
+```
+http://localhost:8081
+```

13-messaging-and-integration-patterns/04-pubsub-amqp/historySvc.js

@@ -0,0 +1,35 @@
+import { createServer } from 'node:http'
+import amqp from 'amqplib' // v0.10.8
+import { Level } from 'level' // v10.0.0
+import { monotonicFactory } from 'ulid' // v3.0.1
+
+const ulid = monotonicFactory()
+const db = new Level('msgHistory', { valueEncoding: 'json' })
+
+const connection = await amqp.connect('amqp://localhost')
+const channel = await connection.createChannel()
+await channel.assertExchange('chat', 'fanout')
+const { queue } = channel.assertQueue('chat_history')
+await channel.bindQueue(queue, 'chat')
+
+channel.consume(queue, async msg => {
+  const data = JSON.parse(msg.content.toString())
+  console.log(`Saving message: ${msg.content.toString()}`)
+  await db.put(ulid(), data)
+  channel.ack(msg)
+})
+
+createServer(async (req, res) => {
+  const url = new URL(req.url, 'http://localhost')
+  const lt = url.searchParams.get('lt')
+  res.writeHead(200, { 'Content-Type': 'application/json' })
+  const messages = []
+  for await (const [key, value] of db.iterator({
+    reverse: true,
+    limit: 10,
+    lt,
+  })) {
+    messages.unshift({ id: key, ...value })
+  }
+  res.end(JSON.stringify(messages, null, 2))
+}).listen(8090)

13-messaging-and-integration-patterns/04-pubsub-amqp/index.js

@@ -0,0 +1,64 @@
+import { createServer } from 'node:http'
+import amqp from 'amqplib' // v0.10.8
+import staticHandler from 'serve-handler' // v6.1.6
+import { WebSocketServer } from 'ws' // v8.18.2
+
+const httpPort = process.argv[2] || 8080
+
+// register the server with RabbitMQ and create a queue
+const connection = await amqp.connect('amqp://localhost')
+const channel = await connection.createChannel()
+await channel.assertExchange('chat', 'fanout')
+const { queue } = await channel.assertQueue(`chat_srv_${httpPort}`, {
+  exclusive: true,
+})
+await channel.bindQueue(queue, 'chat')
+channel.consume(
+  queue,
+  msg => {
+    msg = msg.content.toString()
+    console.log(`From queue: ${msg}`)
+    broadcast(Buffer.from(msg))
+  },
+  { noAck: true }
+)
+
+// serve static files
+const server = createServer((req, res) => {
+  return staticHandler(req, res, { public: 'web' })
+})
+
+const wss = new WebSocketServer({ server })
+wss.on('connection', async client => {
+  console.log('Client connected')
+  client.on('message', msg => {
+    console.log(`Sending message: ${msg}`)
+    channel.publish(
+      'chat',
+      '',
+      Buffer.from(
+        JSON.stringify({
+          text: msg.toString(),
+          timestamp: Date.now(),
+        })
+      )
+    )
+  })
+
+  // load previous messages from the history service
+  const res = await fetch('http://localhost:8090')
+  const messages = await res.json()
+  for (const message of messages) {
+    client.send(Buffer.from(JSON.stringify(message)))
+  }
+})
+
+function broadcast(msg) {
+  for (const client of wss.clients) {
+    if (client.readyState === WebSocket.OPEN) {
+      client.send(msg)
+    }
+  }
+}
+
+server.listen(httpPort)

13-messaging-and-integration-patterns/04-pubsub-amqp/package.json

@@ -0,0 +1,21 @@
+{
+  "name": "04-pubsub-amqp",
+  "version": "1.0.0",
+  "description": "This sample demonstrates how to integrate a chat application and a microservice using AMQP",
+  "type": "module",
+  "scripts": {},
+  "engines": {
+    "node": ">=24"
+  },
+  "engineStrict": true,
+  "keywords": [],
+  "author": "Luciano Mammino and Mario Casciaro",
+  "license": "MIT",
+  "dependencies": {
+    "amqplib": "^0.10.8",
+    "level": "^10.0.0",
+    "serve-handler": "^6.1.6",
+    "ulid": "^3.0.1",
+    "ws": "^8.18.2"
+  }
+}