- 1. API with NestJS #1. Controllers, routing and the module structure
- 2. API with NestJS #2. Setting up a PostgreSQL database with TypeORM
- 3. API with NestJS #3. Authenticating users with bcrypt, Passport, JWT, and cookies
- 4. API with NestJS #4. Error handling and data validation
- 5. API with NestJS #5. Serializing the response with interceptors
- 6. API with NestJS #6. Looking into dependency injection and modules
- 7. API with NestJS #7. Creating relationships with Postgres and TypeORM
- 8. API with NestJS #8. Writing unit tests
- 9. API with NestJS #9. Testing services and controllers with integration tests
- 10. API with NestJS #10. Uploading public files to Amazon S3
- 11. API with NestJS #11. Managing private files with Amazon S3
- 12. API with NestJS #12. Introduction to Elasticsearch
- 13. API with NestJS #13. Implementing refresh tokens using JWT
- 14. API with NestJS #14. Improving performance of our Postgres database with indexes
- 15. API with NestJS #15. Defining transactions with PostgreSQL and TypeORM
- 16. API with NestJS #16. Using the array data type with PostgreSQL and TypeORM
- 17. API with NestJS #17. Offset and keyset pagination with PostgreSQL and TypeORM
- 18. API with NestJS #18. Exploring the idea of microservices
- 19. API with NestJS #19. Using RabbitMQ to communicate with microservices
- 20. API with NestJS #20. Communicating with microservices using the gRPC framework
- 21. API with NestJS #21. An introduction to CQRS
- 22. API with NestJS #22. Storing JSON with PostgreSQL and TypeORM
- 23. API with NestJS #23. Implementing in-memory cache to increase the performance
- 24. API with NestJS #24. Cache with Redis. Running the app in a Node.js cluster
- 25. API with NestJS #25. Sending scheduled emails with cron and Nodemailer
- 26. API with NestJS #26. Real-time chat with WebSockets
- 27. API with NestJS #27. Introduction to GraphQL. Queries, mutations, and authentication
- 28. API with NestJS #28. Dealing in the N + 1 problem in GraphQL
- 29. API with NestJS #29. Real-time updates with GraphQL subscriptions
- 30. API with NestJS #30. Scalar types in GraphQL
- 31. API with NestJS #31. Two-factor authentication
- 32. API with NestJS #32. Introduction to Prisma with PostgreSQL
- 33. API with NestJS #33. Managing PostgreSQL relationships with Prisma
- 34. API with NestJS #34. Handling CPU-intensive tasks with queues
- 35. API with NestJS #35. Using server-side sessions instead of JSON Web Tokens
- 36. API with NestJS #36. Introduction to Stripe with React
- 37. API with NestJS #37. Using Stripe to save credit cards for future use
- 38. API with NestJS #38. Setting up recurring payments via subscriptions with Stripe
- 39. API with NestJS #39. Reacting to Stripe events with webhooks
- 40. API with NestJS #40. Confirming the email address
- 41. API with NestJS #41. Verifying phone numbers and sending SMS messages with Twilio
- 42. API with NestJS #42. Authenticating users with Google
- 43. API with NestJS #43. Introduction to MongoDB
- 44. API with NestJS #44. Implementing relationships with MongoDB
- 45. API with NestJS #45. Virtual properties with MongoDB and Mongoose
- 46. API with NestJS #46. Managing transactions with MongoDB and Mongoose
- 47. API with NestJS #47. Implementing pagination with MongoDB and Mongoose
- 48. API with NestJS #48. Definining indexes with MongoDB and Mongoose
- 49. API with NestJS #49. Updating with PUT and PATCH with MongoDB and Mongoose
- 50. API with NestJS #50. Introduction to logging with the built-in logger and TypeORM
- 51. API with NestJS #51. Health checks with Terminus and Datadog
- 52. API with NestJS #52. Generating documentation with Compodoc and JSDoc
- 53. API with NestJS #53. Implementing soft deletes with PostgreSQL and TypeORM
- 54. API with NestJS #54. Storing files inside a PostgreSQL database
- 55. API with NestJS #55. Uploading files to the server
- 56. API with NestJS #56. Authorization with roles and claims
- 57. API with NestJS #57. Composing classes with the mixin pattern
- 58. API with NestJS #58. Using ETag to implement cache and save bandwidth
- 59. API with NestJS #59. Introduction to a monorepo with Lerna and Yarn workspaces
- 60. API with NestJS #60. The OpenAPI specification and Swagger
- 61. API with NestJS #61. Dealing with circular dependencies
- 62. API with NestJS #62. Introduction to MikroORM with PostgreSQL
- 63. API with NestJS #63. Relationships with PostgreSQL and MikroORM
- 64. API with NestJS #64. Transactions with PostgreSQL and MikroORM
- 65. API with NestJS #65. Implementing soft deletes using MikroORM and filters
- 66. API with NestJS #66. Improving PostgreSQL performance with indexes using MikroORM
- 67. API with NestJS #67. Migrating to TypeORM 0.3
- 68. API with NestJS #68. Interacting with the application through REPL
- 69. API with NestJS #69. Database migrations with TypeORM
- 70. API with NestJS #70. Defining dynamic modules
- 71. API with NestJS #71. Introduction to feature flags
- 72. API with NestJS #72. Working with PostgreSQL using raw SQL queries
- 73. API with NestJS #73. One-to-one relationships with raw SQL queries
- 74. API with NestJS #74. Designing many-to-one relationships using raw SQL queries
- 75. API with NestJS #75. Many-to-many relationships using raw SQL queries
- 76. API with NestJS #76. Working with transactions using raw SQL queries
- 77. API with NestJS #77. Offset and keyset pagination with raw SQL queries
- 78. API with NestJS #78. Generating statistics using aggregate functions in raw SQL
- 79. API with NestJS #79. Implementing searching with pattern matching and raw SQL
- 80. API with NestJS #80. Updating entities with PUT and PATCH using raw SQL queries
- 81. API with NestJS #81. Soft deletes with raw SQL queries
- 82. API with NestJS #82. Introduction to indexes with raw SQL queries
- 83. API with NestJS #83. Text search with tsvector and raw SQL
- 84. API with NestJS #84. Implementing filtering using subqueries with raw SQL
- 85. API with NestJS #85. Defining constraints with raw SQL
- 86. API with NestJS #86. Logging with the built-in logger when using raw SQL
- 87. API with NestJS #87. Writing unit tests in a project with raw SQL
- 88. API with NestJS #88. Testing a project with raw SQL using integration tests
- 89. API with NestJS #89. Replacing Express with Fastify
- 90. API with NestJS #90. Using various types of SQL joins
- 91. API with NestJS #91. Dockerizing a NestJS API with Docker Compose
- 92. API with NestJS #92. Increasing the developer experience with Docker Compose
- 93. API with NestJS #93. Deploying a NestJS app with Amazon ECS and RDS
- 94. API with NestJS #94. Deploying multiple instances on AWS with a load balancer
- 95. API with NestJS #95. CI/CD with Amazon ECS and GitHub Actions
- 96. API with NestJS #96. Running unit tests with CI/CD and GitHub Actions
- 97. API with NestJS #97. Introduction to managing logs with Amazon CloudWatch
- 98. API with NestJS #98. Health checks with Terminus and Amazon ECS
- 99. API with NestJS #99. Scaling the number of application instances with Amazon ECS
- 100. API with NestJS #100. The HTTPS protocol with Route 53 and AWS Certificate Manager
- 101. API with NestJS #101. Managing sensitive data using the AWS Secrets Manager
- 102. API with NestJS #102. Writing unit tests with Prisma
- 103. API with NestJS #103. Integration tests with Prisma
- 104. API with NestJS #104. Writing transactions with Prisma
- 105. API with NestJS #105. Implementing soft deletes with Prisma and middleware
- 106. API with NestJS #106. Improving performance through indexes with Prisma
- 107. API with NestJS #107. Offset and keyset pagination with Prisma
- 108. API with NestJS #108. Date and time with Prisma and PostgreSQL
- 109. API with NestJS #109. Arrays with PostgreSQL and Prisma
- 110. API with NestJS #110. Managing JSON data with PostgreSQL and Prisma
- 111. API with NestJS #111. Constraints with PostgreSQL and Prisma
- 112. API with NestJS #112. Serializing the response with Prisma
- 113. API with NestJS #113. Logging with Prisma
- 114. API with NestJS #114. Modifying data using PUT and PATCH methods with Prisma
- 115. API with NestJS #115. Database migrations with Prisma
- 116. API with NestJS #116. REST API versioning
- 117. API with NestJS #117. CORS – Cross-Origin Resource Sharing
- 118. API with NestJS #118. Uploading and streaming videos
- 119. API with NestJS #119. Type-safe SQL queries with Kysely and PostgreSQL
- 120. API with NestJS #120. One-to-one relationships with the Kysely query builder
- 121. API with NestJS #121. Many-to-one relationships with PostgreSQL and Kysely
- 122. API with NestJS #122. Many-to-many relationships with Kysely and PostgreSQL
- 123. API with NestJS #123. SQL transactions with Kysely
- 124. API with NestJS #124. Handling SQL constraints with Kysely
- 125. API with NestJS #125. Offset and keyset pagination with Kysely
- 126. API with NestJS #126. Improving the database performance with indexes and Kysely
- 127. API with NestJS #127. Arrays with PostgreSQL and Kysely
- 128. API with NestJS #128. Managing JSON data with PostgreSQL and Kysely
- 129. API with NestJS #129. Implementing soft deletes with SQL and Kysely
- 130. API with NestJS #130. Avoiding storing sensitive information in API logs
- 131. API with NestJS #131. Unit tests with PostgreSQL and Kysely
- 132. API with NestJS #132. Handling date and time in PostgreSQL with Kysely
- 133. API with NestJS #133. Introducing database normalization with PostgreSQL and Prisma
- 134. API with NestJS #134. Aggregating statistics with PostgreSQL and Prisma
- 135. API with NestJS #135. Referential actions and foreign keys in PostgreSQL with Prisma
- 136. API with NestJS #136. Raw SQL queries with Prisma and PostgreSQL range types
- 137. API with NestJS #137. Recursive relationships with Prisma and PostgreSQL
- 138. API with NestJS #138. Filtering records with Prisma
- 139. API with NestJS #139. Using UUID as primary keys with Prisma and PostgreSQL
- 140. API with NestJS #140. Using multiple PostgreSQL schemas with Prisma
- 141. API with NestJS #141. Getting distinct records with Prisma and PostgreSQL
- 142. API with NestJS #142. A video chat with WebRTC and React
- 143. API with NestJS #143. Optimizing queries with views using PostgreSQL and Kysely
- 144. API with NestJS #144. Creating CLI applications with the Nest Commander
- 145. API with NestJS #145. Securing applications with Helmet
- 146. API with NestJS #146. Polymorphic associations with PostgreSQL and Prisma
- 147. API with NestJS #147. The data types to store money with PostgreSQL and Prisma
- 148. API with NestJS #148. Understanding the injection scopes
- 149. API with NestJS #149. Introduction to the Drizzle ORM with PostgreSQL
- 150. API with NestJS #150. One-to-one relationships with the Drizzle ORM
- 151. API with NestJS #151. Implementing many-to-one relationships with Drizzle ORM
- 152. API with NestJS #152. SQL constraints with the Drizzle ORM
- 153. API with NestJS #153. SQL transactions with the Drizzle ORM
- 154. API with NestJS #154. Many-to-many relationships with Drizzle ORM and PostgreSQL
- 155. API with NestJS #155. Offset and keyset pagination with the Drizzle ORM
- 156. API with NestJS #156. Arrays with PostgreSQL and the Drizzle ORM
- 157. API with NestJS #157. Handling JSON data with PostgreSQL and the Drizzle ORM
- 158. API with NestJS #158. Soft deletes with the Drizzle ORM
- 159. API with NestJS #159. Date and time with PostgreSQL and the Drizzle ORM
- 160. API with NestJS #160. Using views with the Drizzle ORM and PostgreSQL
- 161. API with NestJS #161. Generated columns with the Drizzle ORM and PostgreSQL
- 162. API with NestJS #162. Identity columns with the Drizzle ORM and PostgreSQL
- 163. API with NestJS #163. Full-text search with the Drizzle ORM and PostgreSQL
- 164. API with NestJS #164. Improving the performance with indexes using Drizzle ORM
- 165. API with NestJS #165. Time intervals with the Drizzle ORM and PostgreSQL
- 166. API with NestJS #166. Logging with the Drizzle ORM
- 167. API with NestJS #167. Unit tests with the Drizzle ORM
- 168. API with NestJS #168. Integration tests with the Drizzle ORM
- 169. API with NestJS #169. Unique IDs with UUIDs using Drizzle ORM and PostgreSQL
- 170. API with NestJS #170. Polymorphic associations with PostgreSQL and Drizzle ORM
- 171. API with NestJS #171. Recursive relationships with Drizzle ORM and PostgreSQL
- 172. API with NestJS #172. Database normalization with Drizzle ORM and PostgreSQL
- 173. API with NestJS #173. Storing money with Drizzle ORM and PostgreSQL
- 174. API with NestJS #174. Multiple PostgreSQL schemas with Drizzle ORM
- 175. API with NestJS #175. PUT and PATCH requests with PostgreSQL and Drizzle ORM
- 176. API with NestJS #176. Database migrations with the Drizzle ORM
- 177. API with NestJS #177. Response serialization with the Drizzle ORM
With WebSockets, we can perform a two-way communication in real-time between the user and the server. Thanks to that, the browser can send messages to the server and listen to information from the other side.
The principles of the WebSocket handshake
WebSocket is a protocol that operates in a different way than HTTP. Even though that’s the case, establishing the connection begins with the client sending an HTTP call that we call a handshake.
The server listens for incoming socket connections using a regular TCP socket. The client sends a GET request to the URL of our socket.
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Request URL: ws://localhost:8080/ Request Method: GET |
Request headers:
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Headers: Connection: Upgrade Upgrade: websocket Sec-WebSocket-Key: 2GruKa/C487njkWNw2HKxQ== |
Above, we can see the Connection: Upgrade and Upgrade: websocket headers. The server understands that the client requests to upgrade the protocol from HTTP to WebSocket. After receiving the above request, the server responds with an indication that the protocol will change from HTTP to WebSocket. The status code of the response is Status Code: 101 Switching Protocols.
Response headers:
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Headers: Connection: Upgrade Upgrade: websocket Sec-WebSocket-Accept: aue6dyRHSJ/yBtny+BQRe0lHOu0= |
In the request, we can also see the Sec-WebSocket-Key header that contains random bytes. The browser adds it to prevent the cache proxy from responding with a previous WebSocket connection. The server hashes the value of the Sec-WebSocket-Key and sends the value through the Sec-WebSocket-Accept. Thanks to that, the client can make sure that it got the correct response.
Implementing the chat functionality in NestJS
In the Node.js world, there are two major solutions to implementing WebSockets. The first of them is called was, and it uses bare WebSockets protocol. The other one is socket.io that provides more features through an additional abstraction.
Currently, the implementation of socket.io for NestJS seems to be more popular than the implementation of ws. Therefore, in this article, we use socket.io.
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npm install @nestjs/websockets @nestjs/platform-socket.io @types/socket.io |
Currently, NestJS does not use the version 3.x of socket.io. Therefore, you need to use the version 2.x of the socket.io-client library on your frontend
The first step in working with WebSockets in NestJS is creating a gateway. Its job is to receive and send messages.
chat.gateway.ts
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import { MessageBody, SubscribeMessage, WebSocketGateway, WebSocketServer, } from '@nestjs/websockets'; import { Server } from 'socket.io'; @WebSocketGateway() export class ChatGateway { @WebSocketServer() server: Server; @SubscribeMessage('send_message') listenForMessages(@MessageBody() data: string) { this.server.sockets.emit('receive_message', data); } } |
In this simple example above, we listen to any incoming send_message events. When that happens, we populate this message to all connected clients. Doing that already gives us a straightforward chat functionality.
In the 24th part of this series, we’ve learned how to use a cluster to run multiple instances of our application. If you implement that approach, you might have trouble when using Socket.IO. To deal with it, you would have to use socket.io-redis, as explained in the official documentation.
Authenticating users
The first thing that we would want to add above is authentication. The most straightforward way of approaching it in our current architecture would be to get the authentication token from the cookies.
If you want to know how we implemented the authentication with cookies, check out API with NestJS #3. Authenticating users with bcrypt, Passport, JWT, and cookies
From the first paragraph of this article, we know that the initial handshake is a regular HTTP request. We can access it along with its headers. To parse the cookie, we use the cookie library.
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npm install cookie @types/cookie |
chat.service.ts
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import { Injectable } from '@nestjs/common'; import { AuthenticationService } from '../authentication/authentication.service'; import { Socket } from 'socket.io'; import { parse } from 'cookie'; import { WsException } from '@nestjs/websockets'; @Injectable() export class ChatService { constructor( private readonly authenticationService: AuthenticationService, ) { } async getUserFromSocket(socket: Socket) { const cookie = socket.handshake.headers.cookie; const { Authentication: authenticationToken } = parse(cookie); const user = await this.authenticationService.getUserFromAuthenticationToken(authenticationToken); if (!user) { throw new WsException('Invalid credentials.'); } return user; } } |
Above, we use the authenticationService.getUserFromAuthenticationToken method. Let’s implement it also.
authentication.service.ts
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import { Injectable } from '@nestjs/common'; import { UsersService } from '../users/users.service'; import { JwtService } from '@nestjs/jwt'; import { ConfigService } from '@nestjs/config'; import TokenPayload from './tokenPayload.interface'; @Injectable() export class AuthenticationService { constructor( private readonly usersService: UsersService, private readonly jwtService: JwtService, private readonly configService: ConfigService ) {} public async getUserFromAuthenticationToken(token: string) { const payload: TokenPayload = this.jwtService.verify(token, { secret: this.configService.get('JWT_ACCESS_TOKEN_SECRET') }); if (payload.userId) { return this.usersService.getById(payload.userId); } } // ... } |
To use the getUserFromSocket method, we need to provide it with the current socket. We can do that in the handleConnection method of our ChatGateway if it implements the OnGatewayConnection interface.
chat.gateway.ts
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import { MessageBody, OnGatewayConnection, SubscribeMessage, WebSocketGateway, WebSocketServer, } from '@nestjs/websockets'; import { Server, Socket } from 'socket.io'; import { ChatService } from './chat.service'; @WebSocketGateway() export class ChatGateway implements OnGatewayConnection { @WebSocketServer() server: Server; constructor( private readonly chatService: ChatService ) { } async handleConnection(socket: Socket) { await this.chatService.getUserFromSocket(socket); } @SubscribeMessage('send_message') listenForMessages(@MessageBody() data: string) { this.server.sockets.emit('receive_message', data); } } |
We can also use the above to authenticate users when they post messages. To do that, let’s modify our listenForMessages method.
chat.gateway.ts
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 |
import { ConnectedSocket, MessageBody, OnGatewayConnection, SubscribeMessage, WebSocketGateway, WebSocketServer, } from '@nestjs/websockets'; import { Server, Socket } from 'socket.io'; import { ChatService } from './chat.service'; @WebSocketGateway() export class ChatGateway implements OnGatewayConnection { @WebSocketServer() server: Server; constructor( private readonly chatService: ChatService ) { } async handleConnection(socket: Socket) { await this.chatService.getUserFromSocket(socket); } @SubscribeMessage('send_message') async listenForMessages( @MessageBody() content: string, @ConnectedSocket() socket: Socket, ) { const author = await this.chatService.getUserFromSocket(socket); this.server.sockets.emit('receive_message', { content, author }); } } |
Now, our users receive both the content of the messages in the chat and the information about the author.
Persisting the messages in the database
So far, we’ve only forwarded incoming messages to all of the connected users. Any new users that join the conversation wouldn’t be able to view its history. To improve that, we need to save all of the messages in the database.
message.entity.ts
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import { Column, Entity, ManyToOne, PrimaryGeneratedColumn } from 'typeorm'; import User from '../users/user.entity'; @Entity() class Message { @PrimaryGeneratedColumn() public id: number; @Column() public content: string; @ManyToOne(() => User) public author: User; } export default Message; |
We also need to implement the logic of saving and retrieving messages. Let’s do that in our ChatService:
chat.service.ts
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import { Injectable } from '@nestjs/common'; import { AuthenticationService } from '../authentication/authentication.service'; import { InjectRepository } from '@nestjs/typeorm'; import Message from './message.entity'; import User from '../users/user.entity'; import { Repository } from 'typeorm'; @Injectable() export class ChatService { constructor( private readonly authenticationService: AuthenticationService, @InjectRepository(Message) private messagesRepository: Repository<Message>, ) { } async saveMessage(content: string, author: User) { const newMessage = await this.messagesRepository.create({ content, author }); await this.messagesRepository.save(newMessage); return newMessage; } async getAllMessages() { return this.messagesRepository.find({ relations: ['author'] }); } // ... } |
The last thing is to use the above functionalities in our ChatGateway:
chat.gateway.ts
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import { ConnectedSocket, MessageBody, OnGatewayConnection, SubscribeMessage, WebSocketGateway, WebSocketServer, } from '@nestjs/websockets'; import { Server, Socket } from 'socket.io'; import { ChatService } from './chat.service'; @WebSocketGateway() export class ChatGateway implements OnGatewayConnection { @WebSocketServer() server: Server; constructor( private readonly chatService: ChatService ) { } async handleConnection(socket: Socket) { await this.chatService.getUserFromSocket(socket); } @SubscribeMessage('send_message') async listenForMessages( @MessageBody() content: string, @ConnectedSocket() socket: Socket, ) { const author = await this.chatService.getUserFromSocket(socket); const message = await this.chatService.saveMessage(content, author); this.server.sockets.emit('receive_message', message); return message; } @SubscribeMessage('request_all_messages') async requestAllMessages( @ConnectedSocket() socket: Socket, ) { await this.chatService.getUserFromSocket(socket); const messages = await this.chatService.getAllMessages(); socket.emit('send_all_messages', messages); } } |
Our clients need to emit the request_all_messages event as soon as they connect for the above to work.
By returning the message object from the listenForMessages method we send and acknowledgment stating that we’ve receive a message correctly.
Summary
In this article, we’ve implemented a chat functionality. To do that, we’ve also learned how WebSockets work and what is a handshake. Although our chat is working, it is still quite basic. For example, it could be improved by adding information about the time of the message. Feel free to experiment and add your own features.
Thank you for article. Will you describe the use of Server-Sent Events with authorization in future?
An awesome list!
Would be nice to see Nest.js + GraphQL (code first / schema first) approaches
Thank you a lot for this article. Can we use Nest.js guards to avoid calling getUserFromSocket for each method? What do you think?
Can use custom decorators
Awesome, I’m reading the whole series, very interesting! One thing that I can’t figure out is how to have some kind of “group”. With the “chat” analogy, it would be to have different rooms for different people. Do you need one gateway per room? Or one gateway but your receive parameters indicating the room? but then how do send message back only to users in the room?
how do we use the Chat API ?
i have the same question
This is cool, but how to use the interceptor created in http://wanago.io/2021/08/23/api-nestjs-relationships-mongodb/?
Great article, it’ll be nice to show how to test what we’ve in the end of the article (how you usually did)
Thanks
I’ve been following your series for quite a while now and I can’t make this exercice work. Maybe I’m not using the right tool (I’m using Postman) but when I connect the socket’s headers do not have cookies.
It would be great if you can provide more explanation about how you tested it.