第三章
给数据库添加 User 模型
用户与文章是一对多的关系，我们可以自己填写完整的依赖关系，也可以利用 prisma 插件帮助我们生成，更新 prisma/schema.prisma 文件, 新增以下内容
model User {
id Int @id @default(autoincrement())
name String?
email String @unique
password String
createAt DateTime @default(now())
updateAt DateTime @updatedAt
articles Article[]
@@map("user")
}
保存文件之后，prisma 插件会自动帮我生成 Article model 内对应的字段，内容如下
model Article {
id Int @id @default(autoincrement())
title String @unique
description String?
body String
published Boolean @default(false)
createdAt DateTime @default(now())
updatedAt DateTime @updatedAt
User User? @relation(fields: [userId], references: [id])
userId Int?
@@map("article")
}
可以看到 Article model 新增了 User和userId 字段， 它们是可选的，也就是说我们可以创建没有作者的文章。我们可以修改一下字段的名称，最终结果如下：
// prisma/schema.prisma
// ...
model Article {
id Int @id @default(autoincrement())
title String @unique
description String?
body String
published Boolean @default(false)
createdAt DateTime @default(now())
updatedAt DateTime @updatedAt
author User? @relation(fields: [authorId], references: [id])
authorId Int?
}
model User {
id Int @id @default(autoincrement())
name String?
email String @unique
password String
createdAt DateTime @default(now())
updatedAt DateTime @updatedAt
articles Article[]
}
要将更改应用到数据库，可以运行 prisma migrate dev
npx prisma migrate dev --name "add-user-model"
访问本地 http://localhost:8080/ 通过 Adminer 查看 user 表已经添加成功
更新 seed 脚本文件
seed 脚本负责用虚拟数据填充数据库，更新脚本以在数据库中创建几个用户。
// 初始化 Prisma Client
import { PrismaClient } from '@prisma/client';
const prisma = new PrismaClient();
async function main() {
const user1 = await prisma.user.upsert({
where: { email: 'sabin@adams.com' },
update: {},
create: {
email: 'sabin@adams.com',
name: 'Sabin Adams',
password: 'password-sabin',
},
});
console.log(user1);
const user2 = await prisma.user.upsert({
where: { email: 'alex@ruheni.com' },
update: {},
create: {
email: 'alex@ruheni.com',
name: 'Alex Ruheni',
password: 'password-alex',
},
});
console.log(user2);
// 创建2个虚拟文章
const post1 = await prisma.article.upsert({
where: { title: 'Prisma Adds Support for MongoDB' },
update: {
authorId: user1.id,
},
create: {
title: 'Prisma Adds Support for MongoDB',
body: 'Support for MongoDB has been one of the most requested features since the initial release of...',
description:
"We are excited to share that today's Prisma ORM release adds stable support for MongoDB!",
published: false,
authorId: user1.id,
},
});
console.log(post1);
// upsert：用于创建或更新，确保在满足 where 条件时更新，否则创建新记录。
const post2 = await prisma.article.upsert({
where: { title: "What's new in Prisma? (Q1/22)" },
update: {
authorId: user2.id,
},
create: {
title: "What's new in Prisma? (Q1/22)",
body: 'Our engineers have been working hard, issuing new releases with many improvements...',
description:
'Learn about everything in the Prisma ecosystem and community from January to March 2022.',
published: true,
authorId: user2.id,
},
});
console.log(post2);
const post3 = await prisma.article.upsert({
where: { title: 'Prisma Client Just Became a Lot More Flexible' },
update: {},
create: {
title: 'Prisma Client Just Became a Lot More Flexible',
body: 'Prisma Client extensions provide a powerful new way to add functionality to Prisma in a type-safe manner...',
description:
'This article will explore various ways you can use Prisma Client extensions to add custom functionality to Prisma Client..',
published: true,
},
});
console.log(post3);
}
// 执行 main 函数
main()
.catch((e) => {
console.log(e);
// 非正常退出进程，不会执行后续任何代码
process.exit(1);
})
.finally(async () => {
// 关闭 Prisma Client
await prisma.$disconnect();
});
执行 seed 脚本，生成数据
npx prisma db seed
向ArticleEntity添加一个authorId字段
运行迁移后，运行项目，你可能会注意到一个新的TypeScript错误。ArticleEntity类实现了Prisma生成的Article类型。Article类型有一个新的authorId字段，但是ArticleEntity类没有定义这个字段。TypeScript识别出了这种类型的不匹配，并抛出了一个错误。您可以通过将authorId字段添加到ArticleEntity类来修复此错误
// src/articles/entities/article.entity.ts
import { Article } from '@prisma/client';
import { ApiProperty } from '@nestjs/swagger';
export class ArticleEntity implements Article {
@ApiProperty()
id: number;
@ApiProperty()
title: string;
@ApiProperty({ required: false, nullable: true })
description: string | null;
@ApiProperty()
body: string;
@ApiProperty()
published: boolean;
@ApiProperty()
createdAt: Date;
@ApiProperty()
updatedAt: Date;
@ApiProperty({ required: false, nullable: true })
authorId: number | null;
}
实现 User 模块的 CRUD
在本节中，我们将实现 User 模块的 rest api，可以对数据库进行 crud。
生成 user 模块的 rest 资源文件
使用下面的命令自动生成文件：
npx nest generate resource
跟随 cli 提示，选择对应的功能，
- What name would you like to use for this resource (plural, e.g., "users")? users
- What transport layer do you use? REST API
- Would you like to generate CRUD entry points? Yes
现在你应该看到 src/users 文件夹了，生成了对应的资源文件。
将 PrismaClient 添加到 User 模块
// src/users/users.module.ts
import { Module } from '@nestjs/common';
import { UsersService } from './users.service';
import { UsersController } from './users.controller';
import { PrismaModule } from 'src/prisma/prisma.module';
@Module({
controllers: [UsersController],
providers: [UsersService],
imports: [PrismaModule],
})
export class UsersModule {}
现在你可以在UsersService中注入PrismaService，并使用它来访问数据库。
// src/users/users.service.ts
import { Injectable } from '@nestjs/common';
import { CreateUserDto } from './dto/create-user.dto';
import { UpdateUserDto } from './dto/update-user.dto';
import { PrismaService } from 'src/prisma/prisma.service';
@Injectable()
export class UsersService {
constructor(private prisma: PrismaService) {}
// CRUD operations
}
定义 User 模块的 entity 和 DTO class
// src/users/entities/user.entity.ts
import { ApiProperty } from '@nestjs/swagger';
import { User } from '@prisma/client';
export class UserEntity implements User {
@ApiProperty()
id: number;
@ApiProperty()
createdAt: Date;
@ApiProperty()
updatedAt: Date;
@ApiProperty()
name: string;
@ApiProperty()
email: string;
password: string;
}
@ApiProperty装饰器用于使属性对Swagger可见。注意，您没有将@ApiProperty装饰器添加到密码字段。这是因为该字段很敏感，您不希望在API中公开它。
DTO（数据传输对象）是一个定义如何通过网络发送数据的对象。您将需要实现CreateUserDto和UpdateUserDto类，分别定义在创建和更新用户时将发送给API的数据。在create-user.dto中定义CreateUserDto类。
// src/users/dto/create-user.dto.ts
import { ApiProperty } from '@nestjs/swagger';
import { IsNotEmpty, IsString, MinLength } from 'class-validator';
export class CreateUserDto {
@IsString()
@IsNotEmpty()
@ApiProperty()
name: string;
@IsString()
@IsNotEmpty()
@ApiProperty()
email: string;
@IsString()
@IsNotEmpty()
@MinLength(6)
@ApiProperty()
password: string;
}
定义 UserService class
完善 UserService class 内部 create(), findAll(), findOne(), update() and remove() 的方法。
// src/users/users.service.ts
import { Injectable } from '@nestjs/common';
import { CreateUserDto } from './dto/create-user.dto';
import { UpdateUserDto } from './dto/update-user.dto';
import { PrismaService } from 'src/prisma/prisma.service';
@Injectable()
export class UsersService {
constructor(private prisma: PrismaService) {}
create(createUserDto: CreateUserDto) {
return this.prisma.user.create({ data: createUserDto });
}
findAll() {
return this.prisma.user.findMany();
}
findOne(id: number) {
return this.prisma.user.findUnique({ where: { id } });
}
update(id: number, updateUserDto: UpdateUserDto) {
return this.prisma.user.update({ where: { id }, data: updateUserDto });
}
remove(id: number) {
return this.prisma.user.delete({ where: { id } });
}
}
定义 UserController class
UsersController负责处理客户端的请求和响应。它将利用UsersService来访问数据库，利用UserEntity来定义响应体，利用CreateUserDto和UpdateUserDto来定义请求体。
下面我们来完善下面5个接口：
- create() - POST /users
- findAll() - GET /users
- findOne() - GET /users/:id
- update() - PATCH /users/:id
- remove() - DELETE /users/:id
// src/users/users.controller.ts
import {
Controller,
Get,
Post,
Body,
Patch,
Param,
Delete,
ParseIntPipe,
} from '@nestjs/common';
import { UsersService } from './users.service';
import { CreateUserDto } from './dto/create-user.dto';
import { UpdateUserDto } from './dto/update-user.dto';
import { ApiCreatedResponse, ApiOkResponse, ApiTags } from '@nestjs/swagger';
import { UserEntity } from './entities/user.entity';
@Controller('users')
@ApiTags('users')
export class UsersController {
constructor(private readonly usersService: UsersService) {}
@Post()
@ApiCreatedResponse({ type: UserEntity })
create(@Body() createUserDto: CreateUserDto) {
return this.usersService.create(createUserDto);
}
@Get()
@ApiOkResponse({ type: UserEntity, isArray: true })
findAll() {
return this.usersService.findAll();
}
@Get(':id')
@ApiOkResponse({ type: UserEntity })
findOne(@Param('id', ParseIntPipe) id: number) {
return this.usersService.findOne(id);
}
@Patch(':id')
@ApiCreatedResponse({ type: UserEntity })
update(
@Param('id', ParseIntPipe) id: number,
@Body() updateUserDto: UpdateUserDto,
) {
return this.usersService.update(id, updateUserDto);
}
@Delete(':id')
@ApiOkResponse({ type: UserEntity })
remove(@Param('id', ParseIntPipe) id: number) {
return this.usersService.remove(id);
}
}
从响应体中排除密码字段
当我们查询某个用户的时候，响应体将用户的 password 也返回了，这是不符合实际需求的。
有2种方法可以修复这个问题：
- 在控制器路由处理程序中手动从响应体中删除密码
- 使用拦截器自动从响应体中删除密码
第一种方法很容易出错，所以我们将学习如何使用拦截器
使用 ClassSerializerInterceptor 从响应体中删除字段
NestJS有一个内置的ClassSerializerInterceptor，可以用来转换对象。您将使用这个拦截器从响应对象中删除密码字段。
首先更新 main.ts 全局启用ClassSerializerInterceptor
// src/main.ts
import { NestFactory, Reflector } from '@nestjs/core';
import { AppModule } from './app.module';
import { SwaggerModule, DocumentBuilder } from '@nestjs/swagger';
import { ClassSerializerInterceptor, ValidationPipe } from '@nestjs/common';
async function bootstrap() {
const app = await NestFactory.create(AppModule);
app.useGlobalPipes(new ValidationPipe({ whitelist: true }));
app.useGlobalInterceptors(new ClassSerializerInterceptor(app.get(Reflector)));
const config = new DocumentBuilder()
.setTitle('Median')
.setDescription('The Median API description')
.setVersion('0.1')
.build();
const document = SwaggerModule.createDocument(app, config);
SwaggerModule.setup('api', app, document);
await app.listen(3000);
}
bootstrap();
ClassSerializerInterceptor 使用类转换器包来定义如何转换对象。使用 @Exclude() 装饰器来排除UserEntity类中的password字段：
// src/users/entities/user.entity.ts
import { ApiProperty } from '@nestjs/swagger';
import { User } from '@prisma/client';
import { Exclude } from 'class-transformer';
export class UserEntity implements User {
@ApiProperty()
id: number;
@ApiProperty()
createdAt: Date;
@ApiProperty()
updatedAt: Date;
@ApiProperty()
name: string;
@ApiProperty()
email: string;
@Exclude()
password: string;
}
再次查询用户详情，你会发现 password 字段依旧被返回了。这是因为，当前控制器中的路由处理程序返回由Prisma Client生成的User类型。ClassSerializerInterceptor只适用于用@Exclude（）装饰器装饰的类。在本例中，它是UserEntity类。所以，你需要更新路由处理程序来返回UserEntity类型。
// src/users/entities/user.entity.ts
import { ApiProperty } from '@nestjs/swagger';
import { User } from '@prisma/client';
import { Exclude } from 'class-transformer';
export class UserEntity implements User {
constructor(partial: Partial<UserEntity>) {
Object.assign(this, partial);
}
@ApiProperty()
id: number;
@ApiProperty()
createdAt: Date;
@ApiProperty()
updatedAt: Date;
@ApiProperty()
name: string;
@ApiProperty()
email: string;
@Exclude()
password: string;
}
构造函数接受一个对象，并使用 object.assign() 方法将部分对象的属性复制到UserEntity实例。partial 的类型是 partial。这意味着部分对象可以包含 UserEntity 类中定义的属性的任何子集。
下一步，更新 UserController 路由处理程序，返回 UserEntity 而不是 Prisma.User。
// src/users/users.controller.ts
@Controller('users')
@ApiTags('users')
export class UsersController {
constructor(private readonly usersService: UsersService) {}
@Post()
@ApiCreatedResponse({ type: UserEntity })
async create(@Body() createUserDto: CreateUserDto) {
return new UserEntity(await this.usersService.create(createUserDto));
}
@Get()
@ApiOkResponse({ type: UserEntity, isArray: true })
async findAll() {
const users = await this.usersService.findAll();
return users.map((user) => new UserEntity(user));
}
@Get(':id')
@ApiOkResponse({ type: UserEntity })
async findOne(@Param('id', ParseIntPipe) id: number) {
return new UserEntity(await this.usersService.findOne(id));
}
@Patch(':id')
@ApiCreatedResponse({ type: UserEntity })
async update(
@Param('id', ParseIntPipe) id: number,
@Body() updateUserDto: UpdateUserDto,
) {
return new UserEntity(await this.usersService.update(id, updateUserDto));
}
@Delete(':id')
@ApiOkResponse({ type: UserEntity })
async remove(@Param('id', ParseIntPipe) id: number) {
return new UserEntity(await this.usersService.remove(id));
}
}
再次查询用户详情，发现 password 字段已经不再返回了。
将作者连同文章一起返回
前面我们已经实现查询文章的接口，只需要简单修改一下就能将关联的作者信息返回了。
// src/articles/articles.service.ts
findOne(id: number) {
return this.prisma.article.findUnique({
where: { id },
include: {
author: true,
},
});
}
现在文章关联的作者信息也返回出来了，但是用户信息里携带了 password, 这个问题跟前面的问题类似。首先修改 ArticleEntity，将 author 返回改为 UserEntity。(这个 UserEntity 前面我们已经使用拦截器去除了 password 字段)。然后修改 ArticlesController 将返回从 prisma.article 改成 ArticleEntity。
// src/articles/entities/article.entity.ts
import { Article } from '@prisma/client';
import { ApiProperty } from '@nestjs/swagger';
import { UserEntity } from 'src/users/entities/user.entity';
export class ArticleEntity implements Article {
@ApiProperty()
id: number;
@ApiProperty()
title: string;
@ApiProperty({ required: false, nullable: true })
description: string | null;
@ApiProperty()
body: string;
@ApiProperty()
published: boolean;
@ApiProperty()
createdAt: Date;
@ApiProperty()
updatedAt: Date;
@ApiProperty({ required: false, nullable: true })
authorId: number | null;
@ApiProperty({ required: false, type: UserEntity })
author?: UserEntity;
constructor({ author, ...data }: Partial<ArticleEntity>) {
Object.assign(this, data);
if (author) {
this.author = new UserEntity(author);
}
}
}
// src/articles/articles.controller.ts
import {
Controller,
Get,
Post,
Body,
Patch,
Param,
Delete,
ParseIntPipe,
} from '@nestjs/common';
import { ArticlesService } from './articles.service';
import { CreateArticleDto } from './dto/create-article.dto';
import { UpdateArticleDto } from './dto/update-article.dto';
import { ApiCreatedResponse, ApiOkResponse, ApiTags } from '@nestjs/swagger';
import { ArticleEntity } from './entities/article.entity';
@Controller('articles')
@ApiTags('articles')
export class ArticlesController {
constructor(private readonly articlesService: ArticlesService) {}
@Post()
@ApiCreatedResponse({ type: ArticleEntity })
async create(@Body() createArticleDto: CreateArticleDto) {
return new ArticleEntity(
await this.articlesService.create(createArticleDto),
);
}
@Get()
@ApiOkResponse({ type: ArticleEntity, isArray: true })
async findAll() {
const articles = await this.articlesService.findAll();
return articles.map((article) => new ArticleEntity(article));
}
@Get('drafts')
@ApiOkResponse({ type: ArticleEntity, isArray: true })
async findDrafts() {
const drafts = await this.articlesService.findDrafts();
return drafts.map((draft) => new ArticleEntity(draft));
}
@Get(':id')
@ApiOkResponse({ type: ArticleEntity })
async findOne(@Param('id', ParseIntPipe) id: number) {
return new ArticleEntity(await this.articlesService.findOne(id));
}
@Patch(':id')
@ApiCreatedResponse({ type: ArticleEntity })
async update(
@Param('id', ParseIntPipe) id: number,
@Body() updateArticleDto: UpdateArticleDto,
) {
return new ArticleEntity(
await this.articlesService.update(id, updateArticleDto),
);
}
@Delete(':id')
@ApiOkResponse({ type: ArticleEntity })
async remove(@Param('id', ParseIntPipe) id: number) {
return new ArticleEntity(await this.articlesService.remove(id));
}
}
参考资料 Building a REST API with NestJS and Prisma: Handling Relational Data
