Vatsalya-singhi

// Custom Pipe used in a Controller
import { Controller, Post, Body } from '@nestjs/common';
import { UppercasePipe } from './uppercase.pipe';

@Controller('users')
export class UsersController {
  @Post()
  create(@Body('name', new UppercasePipe()) name: string) {
    return { message: 'User created', name };
  }

Vatsalya-singhi

import { IsString, IsInt, MinLength, Min } from 'class-validator';

export class CreateUserDto {
  @IsString()
  @MinLength(3)
  name: string;

  @IsInt()
  @Min(18)
  age: number;

Vatsalya-singhi

import { Controller, Post, Body, UsePipes, ValidationPipe } from '@nestjs/common';
import { CreateUserDto } from './create-user.dto';

@Controller('users')
export class UsersController {
  @Post()
  @UsePipes(new ValidationPipe()) // Apply validation
  create(@Body() createUserDto: CreateUserDto) {
    return { message: 'User created', data: createUserDto };
  }

Vatsalya-singhi

// main.ts
import { NestFactory } from '@nestjs/core';
import { AppModule } from './app.module';
import { ValidationPipe } from '@nestjs/common';

async function bootstrap() {
  const app = await NestFactory.create(AppModule);
  app.useGlobalPipes(new ValidationPipe()); // Apply to all routes
  await app.listen(3000);
}

Vatsalya-singhi

import { Injectable, CanActivate, ExecutionContext } from '@nestjs/common';

@Injectable()
export class AuthGuard implements CanActivate {
  canActivate(context: ExecutionContext): boolean {
    const request = context.switchToHttp().getRequest();
    // Check if request has a valid user (authentication logic)
    return Boolean(request.user);  // Assume `request.user` is set after successful login
  }
}

Vatsalya-singhi

import { Controller, Get, UseGuards } from '@nestjs/common';
import { AuthGuard } from './auth.guard';

@Controller('users')
export class UsersController {
  @Get()
  @UseGuards(AuthGuard) // Apply guard to this method
  findAll() {
    return { message: 'List of users' };
  }

Vatsalya-singhi

import { Controller, Get, UseGuards } from '@nestjs/common';
import { AuthGuard } from './auth.guard';

@Controller('users')
@UseGuards(AuthGuard) // Apply guard to all routes in this controller
export class UsersController {
  @Get()
  findAll() {
    return { message: 'List of users' };
  }

Vatsalya-singhi

// main.ts
import { NestFactory } from '@nestjs/core';
import { AppModule } from './app.module';
import { AuthGuard } from './auth.guard';

async function bootstrap() {
  const app = await NestFactory.create(AppModule);
  app.useGlobalGuards(new AuthGuard()); // Apply globally
  await app.listen(3000);
}

Vatsalya-singhi

import { Injectable, CanActivate, ExecutionContext } from '@nestjs/common';

@Injectable()
export class RoleGuard implements CanActivate {
  constructor(private requiredRole: string) {}

  canActivate(context: ExecutionContext): boolean {
    const request = context.switchToHttp().getRequest();
    const user = request.user;  // User is assumed to be attached to the request
    return user?.role === this.requiredRole;  // Check if user's role matches

Vatsalya-singhi

// guard implementation in Controller
import { Controller, Get, UseGuards } from '@nestjs/common';
import { RoleGuard } from './role.guard';

@Controller('admin')
export class AdminController {
  @Get()
  @UseGuards(new RoleGuard('admin')) // Apply the guard for 'admin' role
  findAll() {
    return { message: 'Admin dashboard' };