Part 2: Building a REST API with NestJS and Prisma: Input Validation & Transformation

package.json

@@ -25,6 +25,8 @@
     "@nestjs/platform-express": "^9.0.0",
     "@nestjs/swagger": "^6.3.0",
     "@prisma/client": "^4.12.0",
+    "class-transformer": "^0.5.1",
+    "class-validator": "^0.14.0",
     "reflect-metadata": "^0.1.13",
     "rxjs": "^7.2.0",
     "swagger-ui-express": "^4.6.2"

src/articles/articles.controller.ts

@@ -1,4 +1,4 @@
-import { Controller, Get, Post, Body, Patch, Param, Delete } from '@nestjs/common';
+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';
@@ -30,19 +30,19 @@ export class ArticlesController {
 
   @Get(':id')
   @ApiOkResponse({ type: ArticleEntity })
-  findOne(@Param('id') id: string) {
-    return this.articlesService.findOne(+id);
+  findOne(@Param('id', ParseIntPipe) id: number) {
+    return this.articlesService.findOne(id);
   }
 
   @Patch(':id')
   @ApiOkResponse({ type: ArticleEntity })
-  update(@Param('id') id: string, @Body() updateArticleDto: UpdateArticleDto) {
-    return this.articlesService.update(+id, updateArticleDto);
+  update(@Param('id', ParseIntPipe) id: number, @Body() updateArticleDto: UpdateArticleDto) {
+    return this.articlesService.update(id, updateArticleDto);
   }
 
   @Delete(':id')
   @ApiOkResponse({ type: ArticleEntity })
-  remove(@Param('id') id: string) {
-    return this.articlesService.remove(+id);
+  remove(@Param('id', ParseIntPipe) id: number) {
+    return this.articlesService.remove(id);
   }
 }

src/articles/dto/create-article.dto.ts

@@ -1,15 +1,27 @@
 import { ApiProperty } from '@nestjs/swagger'
+import { IsBoolean, IsNotEmpty, IsOptional, IsString, MaxLength, MinLength } from 'class-validator'
 
 export class CreateArticleDto {
+    @IsString()
+    @IsNotEmpty()
+    @MinLength(5)
     @ApiProperty()
     title: string
 
+    @IsString()
+    @IsOptional()
+    @IsNotEmpty()
+    @MaxLength(300)
     @ApiProperty({ required: false })
     description?: string
 
+    @IsString()
+    @IsNotEmpty()
     @ApiProperty()
     body: string
 
+    @IsBoolean()
+    @IsOptional()
     @ApiProperty({ required: false, default: false })
     published?: boolean = false
 }

src/main.ts

@@ -1,10 +1,13 @@
 import { NestFactory } from '@nestjs/core';
 import { AppModule } from './app.module';
 import { SwaggerModule, DocumentBuilder } from '@nestjs/swagger';
+import { ValidationPipe } from '@nestjs/common'
 
 async function bootstrap() {
   const app = await NestFactory.create(AppModule);
 
+  app.useGlobalPipes(new ValidationPipe({ whitelist: true }))
+
   const config = new DocumentBuilder()
     .setTitle('Median')
     .setDescription('The Median API description')

yarn.lock

@@ -1046,6 +1046,11 @@
   dependencies:
     "@types/superagent" "*"
 
+"@types/validator@^13.7.10":
+  version "13.7.15"
+  resolved "https://registry.yarnpkg.com/@types/validator/-/validator-13.7.15.tgz#408c99d1b5f0eecc78109c11f896f72d1f026a10"
+  integrity sha512-yeinDVQunb03AEP8luErFcyf/7Lf7AzKCD0NXfgVoGCCQDNpZET8Jgq74oBgqKld3hafLbfzt/3inUdQvaFeXQ==
+
 "@types/yargs-parser@*":
   version "21.0.0"
   resolved "https://registry.yarnpkg.com/@types/yargs-parser/-/yargs-parser-21.0.0.tgz#0c60e537fa790f5f9472ed2776c2b71ec117351b"
@@ -1695,6 +1700,20 @@ cjs-module-lexer@^1.0.0:
   resolved "https://registry.yarnpkg.com/cjs-module-lexer/-/cjs-module-lexer-1.2.2.tgz#9f84ba3244a512f3a54e5277e8eef4c489864e40"
   integrity sha512-cOU9usZw8/dXIXKtwa8pM0OTJQuJkxMN6w30csNRUerHfeQ5R6U3kkU/FtJeIf3M202OHfY2U8ccInBG7/xogA==
 
+class-transformer@^0.5.1:
+  version "0.5.1"
+  resolved "https://registry.yarnpkg.com/class-transformer/-/class-transformer-0.5.1.tgz#24147d5dffd2a6cea930a3250a677addf96ab336"
+  integrity sha512-SQa1Ws6hUbfC98vKGxZH3KFY0Y1lm5Zm0SY8XX9zbK7FJCyVEac3ATW0RIpwzW+oOfmHE5PMPufDG9hCfoEOMw==
+
+class-validator@^0.14.0:
+  version "0.14.0"
+  resolved "https://registry.yarnpkg.com/class-validator/-/class-validator-0.14.0.tgz#40ed0ecf3c83b2a8a6a320f4edb607be0f0df159"
+  integrity sha512-ct3ltplN8I9fOwUd8GrP8UQixwff129BkEtuWDKL5W45cQuLd19xqmTLu5ge78YDm/fdje6FMt0hGOhl0lii3A==
+  dependencies:
+    "@types/validator" "^13.7.10"
+    libphonenumber-js "^1.10.14"
+    validator "^13.7.0"
+
 cli-cursor@^3.1.0:
   version "3.1.0"
   resolved "https://registry.yarnpkg.com/cli-cursor/-/cli-cursor-3.1.0.tgz#264305a7ae490d1d03bf0c9ba7c925d1753af307"
@@ -3311,6 +3330,11 @@ levn@^0.4.1:
     prelude-ls "^1.2.1"
     type-check "~0.4.0"
 
+libphonenumber-js@^1.10.14:
+  version "1.10.26"
+  resolved "https://registry.yarnpkg.com/libphonenumber-js/-/libphonenumber-js-1.10.26.tgz#3e6604357b3434b0005f85778b44153f4fadeecd"
+  integrity sha512-oB3l4J5gEhMV+ymmlIjWedsbCpsNRqbEZ/E/MpN2QVyinKNra6DcuXywxSk/72M3DZDoH/6kzurOq1erznBMwQ==
+
 lines-and-columns@^1.1.6:
   version "1.2.4"
   resolved "https://registry.yarnpkg.com/lines-and-columns/-/lines-and-columns-1.2.4.tgz#eca284f75d2965079309dc0ad9255abb2ebc1632"
@@ -4626,6 +4650,11 @@ v8-to-istanbul@^9.0.1:
     "@types/istanbul-lib-coverage" "^2.0.1"
     convert-source-map "^1.6.0"
 
+validator@^13.7.0:
+  version "13.9.0"
+  resolved "https://registry.yarnpkg.com/validator/-/validator-13.9.0.tgz#33e7b85b604f3bbce9bb1a05d5c3e22e1c2ff855"
+  integrity sha512-B+dGG8U3fdtM0/aNK4/X8CXq/EcxU2WPrPEkJGslb47qyHsxmbggTWK0yEA4qnYVNF+nxNlN88o14hIcPmSIEA==
+
 vary@^1, vary@~1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/vary/-/vary-1.1.2.tgz#2299f02c6ded30d4a5961b0b9f74524a18f634fc"