没有为类验证器找到元数据

Question

我正在尝试使用ValidationPipe，但无论我如何编写代码，我在发送请求时都会收到以下警告：No metadata found. There is more than once class-validator version installed probably. You need to flatten your dependencies。

我的路线看起来像这样：

@Get()
@UsePipes(new ValidationPipe({ transform: true }))
async findAll(@Query() queryDto: QueryDto) {
    return await this.myService.findAll(queryDto);
}

我的DTO看起来像这样：

export class queryDto
{
    @ApiModelProperty({
        description: 'Maximum number of results',
        type: Number,
        example: 50,
        default: 50,
        required: false
    })
    readonly limit: number = 50;
}

我尝试使用ValidationPipe几种方式，跟随the doc，但没有什么对我有用。我知道它不起作用，因为虽然请求获得了响应，但是当我的查询为空时，我在DTO中为属性limit写的默认值50不会被使用。因此，当查询中没有提供limit时，limit的值是未定义的，而它应该是50（这意味着不使用ValidationPipe）。

我的package.json似乎是正确的：

npm ls class-validator
[email protected] /home/pierre_t/Bureau/dev/ApiSport
└── [email protected]

完整的package.json：

{
  "name": "api-sport",
  "version": "0.0.1",
  "description": "",
  "author": "",
  "license": "MIT",
  "scripts": {
    "build": "tsc -p tsconfig.build.json",
    "format": "prettier --write \"src/**/*.ts\"",
    "start": "ts-node -r tsconfig-paths/register src/main.ts",
    "start:dev": "nodemon",
    "start:debug": "nodemon --config nodemon-debug.json",
    "start:prod": "pm2 start ./src/main.js --no-daemon",
    "lint": "tslint -p tsconfig.json -c tslint.json",
    "test": "jest",
    "test:watch": "jest --watch",
    "test:cov": "jest --coverage",
    "test:debug": "node --inspect-brk -r tsconfig-paths/register -r ts-node/register node_modules/.bin/jest --runInBand",
    "test:e2e": "jest --config ./test/jest-e2e.json"
  },
  "dependencies": {
    "@nestjs/common": "^6.0.5",
    "@nestjs/core": "^6.0.5",
    "@nestjs/platform-express": "^6.0.5",
    "@nestjs/swagger": "^3.0.1",
    "@nestjs/typeorm": "^6.0.0",
    "@types/lodash": "^4.14.123",
    "class-transformer": "^0.2.0",
    "class-validator": "^0.9.1",
    "dotenv": "^7.0.0",
    "hbs": "^4.0.3",
    "mysql": "^2.16.0",
    "pm2": "^3.4.1",
    "reflect-metadata": "^0.1.12",
    "rimraf": "^2.6.2",
    "rxjs": "^6.3.3",
    "swagger-ui-express": "^4.0.2",
    "typeorm": "^0.2.16"
  },
  "devDependencies": {
    "@nestjs/testing": "^6.0.5",
    "@types/express": "^4.16.0",
    "@types/jest": "^23.3.13",
    "@types/node": "^10.14.4",
    "@types/supertest": "^2.0.7",
    "jest": "^23.6.0",
    "nodemon": "^1.18.9",
    "prettier": "^1.15.3",
    "supertest": "^3.4.1",
    "ts-jest": "^23.10.5",
    "ts-node": "^7.0.1",
    "tsconfig-paths": "^3.7.0",
    "tslint": "5.12.1",
    "typescript": "^3.4.1"
  },
  "jest": {
    "moduleFileExtensions": [
      "js",
      "json",
      "ts"
    ],
    "rootDir": "src",
    "testRegex": ".spec.ts$",
    "transform": {
      "^.+\\.(t|j)s$": "ts-jest"
    },
    "coverageDirectory": "../coverage",
    "testEnvironment": "node"
  }
}

为什么我会收到此消息，如何使用ValidationPipe？

Answer 1

这是因为你使用class-validator但没有任何验证，请参阅此issue：

基本上，它警告您在存储中没有任何元数据，这意味着您没有使用类验证器中的任何装饰器。这意味着您不执行任何验证，因此您应该将validate: false选项传递给buildSchema以禁用自动验证。

我不确定你是否可以对nest的ValidationPipe进行验证，但是你也可以在你的dto中添加一个断言（如果有意义的话），例如：

import { Min } from 'class-validator';
export class QueryDto {
    @Min(1)
    readonly limit: number = 50;
}

---

顺便说一下：由于你的@Query只有字符串属性，你可能想要将你的limit从string变换为number。看看这个answer。