add decorators, filters, interceptors, guards, pipes

src/app.controller.ts

@@ -0,0 +1,26 @@
+import {
+  Body,
+  Controller,
+  Get,
+  Post,
+  UseGuards,
+  UsePipes,
+} from '@nestjs/common';
+import { UserAgentDecorator } from './common/decorators/user-agent.decorator';
+import { AuthGuard } from './common/guards/auth.guard';
+import { StringToLowercasePipe } from './common/pipes/string-to-lowercase.pipe';
+
+@Controller()
+export class AppController {
+  @UsePipes(StringToLowercasePipe)
+  @Post()
+  create(@Body('title') title: string) {
+    return `Movie ${title}`;
+  }
+
+  @UseGuards(AuthGuard)
+  @Get()
+  getProfile(@UserAgentDecorator() userAgent: string) {
+    return { name: 'FirstName', age: 22, userAgent };
+  }
+}

src/app.module.ts

@@ -1,5 +1,6 @@
 import { Module } from '@nestjs/common';
 import { ConfigModule } from '@nestjs/config';
+import { AppController } from './app.controller';
 import { TaskModule } from './task/task.module';
 import { MovieModule } from './movie/movie.module';
 import { ReviewModule } from './review/review.module';
@@ -17,7 +18,7 @@ import { PrismaModule } from './prisma/prisma.module';
     ReviewModule,
     ActorModule,
   ],
-  controllers: [],
+  controllers: [AppController],
   providers: [],
 })
 export class AppModule {}

src/common/decorators/user-agent.decorator.ts

@@ -0,0 +1,9 @@
+import { createParamDecorator, ExecutionContext } from '@nestjs/common';
+import { Request } from 'express';
+
+export const UserAgentDecorator = createParamDecorator(
+  (_data: unknown, context: ExecutionContext) => {
+    const request: Request = context.switchToHttp().getRequest();
+    return request.headers['user-agent'];
+  },
+);

src/common/filters/all-exceptions.filter.ts

@@ -0,0 +1,34 @@
+import {
+  ArgumentsHost,
+  Catch,
+  ExceptionFilter,
+  HttpException,
+  Logger,
+} from '@nestjs/common';
+import { Request, Response } from 'express';
+
+@Catch()
+export class AllExceptionsFilter implements ExceptionFilter {
+  private readonly logger = new Logger(AllExceptionsFilter.name);
+  catch(exception: any, host: ArgumentsHost): any {
+    const context = host.switchToHttp();
+    const response: Response = context.getResponse();
+    const request: Request = context.getRequest();
+
+    const status =
+      exception instanceof HttpException ? exception.getStatus() : 500;
+    const message =
+      exception instanceof HttpException
+        ? exception.message
+        : 'Internal server error';
+
+    this.logger.error(message, exception);
+
+    response.status(status).json({
+      status,
+      message,
+      timestamp: new Date().toISOString(),
+      path: request.baseUrl,
+    });
+  }
+}

src/common/guards/auth.guard.ts

@@ -0,0 +1,24 @@
+import {
+  CanActivate,
+  ExecutionContext,
+  Injectable,
+  UnauthorizedException,
+} from '@nestjs/common';
+import { Request } from 'express';
+import { Observable } from 'rxjs';
+
+@Injectable()
+export class AuthGuard implements CanActivate {
+  canActivate(
+    context: ExecutionContext,
+  ): boolean | Promise<boolean> | Observable<boolean> {
+    const request: Request = context.switchToHttp().getRequest();
+    const token = request.headers.authorization;
+
+    if (!token || !token.startsWith('Bearer')) {
+      throw new UnauthorizedException('You are not authorized');
+    }
+
+    return true;
+  }
+}

src/common/interceptors/response.interceptor.ts

@@ -0,0 +1,22 @@
+import {
+  CallHandler,
+  ExecutionContext,
+  Injectable,
+  NestInterceptor,
+} from '@nestjs/common';
+import { map, Observable } from 'rxjs';
+
+@Injectable()
+export class ResponseInterceptor implements NestInterceptor {
+  intercept(
+    context: ExecutionContext,
+    next: CallHandler<any>,
+  ): Observable<any> {
+    return next.handle().pipe(
+      map((data) => ({
+        status: 'OK',
+        data,
+      })),
+    );
+  }
+}

src/common/pipes/string-to-lowercase.pipe.ts

@@ -0,0 +1,12 @@
+import { ArgumentMetadata, Injectable, PipeTransform } from '@nestjs/common';
+
+@Injectable()
+export class StringToLowercasePipe implements PipeTransform {
+  transform(value: any, metadata: ArgumentMetadata): any {
+    if (typeof value === 'string') {
+      return value.toLocaleLowerCase();
+    }
+
+    return value;
+  }
+}

src/main.ts

@@ -1,12 +1,16 @@
 import { NestFactory } from '@nestjs/core';
 import { AppModule } from './app.module';
 import { ValidationPipe } from '@nestjs/common';
+import { AllExceptionsFilter } from './common/filters/all-exceptions.filter';
+import { ResponseInterceptor } from './common/interceptors/response.interceptor';
 import { loggerMiddlewareFunc } from './common/middlewares/logger/logger.middleware';
 
 async function bootstrap() {
   const app = await NestFactory.create(AppModule);
   app.useGlobalPipes(new ValidationPipe());
   app.use(loggerMiddlewareFunc);
+  app.useGlobalInterceptors(new ResponseInterceptor());
+  app.useGlobalFilters(new AllExceptionsFilter());
   await app.listen(process.env.PORT ?? 3000);
 }
 bootstrap();