Javascript - Use Response object in service Nestjs

LXT
July 16, 2024
202 views
0 votes
2 Answers

I have this controller

@Post('/login')
  async login(@Res() res: Response, @Body() body: LoginDto) {
    try {
      const user = await this.authService.login(body);
      return ResponseUtil.success(res, user, 'nice');
    } catch (error) {
      return ResponseUtil.serverError(res, error.stack);
    }
  }

I want to use res in authService without passing down res like this:

const user = await this.authService.login(res, body);

Or how can I use res in global?

Answers

You can use dependency injection and global interceptor/middlewar to use response object from NestJS in your service without passing it down through method parameters

Create a file response.decorator.ts


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

export const Res = createParamDecorator(
  (data: unknown, ctx: ExecutionContext) => {
    const response = ctx.switchToHttp().getResponse();
    return response;
  },
);

Create a auth.controller.ts

import { Controller, Post, Body, UseInterceptors } from '@nestjs/common';
import { AuthService } from './auth.service';
import { Res } from './response.decorator';
import { Response } from 'express';
import { ResponseUtil } from './response.util'; 
@Controller('auth')
export class AuthController {
  constructor(private readonly authService: AuthService) {}

  @Post('/login')
  async login(@Res() res: Response, @Body() body: LoginDto) {
    try {
      const user = await this.authService.login(body, res);
      return ResponseUtil.success(res, user, 'nice');
    } catch (error) {
      return ResponseUtil.serverError(res, error.stack);
    }
  }
}

Create a auth.service.ts

import { Injectable, Inject } from '@nestjs/common';
import { Response } from 'express';
import { REQUEST } from '@nestjs/core';
import { RequestContext } from './request.context'; // Assuming this context holds the current request

@Injectable()
export class AuthService {
  constructor(@Inject(REQUEST) private readonly requestContext: RequestContext) {}

  async login(body: LoginDto) {
    const res: Response = this.requestContext.getResponse();
    // Now you can use res here as you want
    if (!res) {
      throw new Error('Response object not found');
    }
    
    // here is how you can use it
    // res.status(200).json({ message: 'Success' });

    // Add Your login logic here
  }
}

To access res in authService without passing it explicitly, we can make a combination of a custom provider and middleware in NestJS.

Create a Response Provider

import { Injectable, Scope } from '@nestjs/common';
import { Response } from 'express';

@Injectable({ scope: Scope.REQUEST })
export class ResponseProvider {
  private response: Response;

  setResponse(response: Response) {
    this.response = response;
  }

  getResponse(): Response {
    return this.response;
  }
}

Create Middleware to Inject Response

import { Injectable, NestMiddleware } from '@nestjs/common';
import { Request, Response, NextFunction } from 'express';
import { ResponseProvider } from './response.provider'; // Adjust the import

@Injectable()
export class ResponseMiddleware implements NestMiddleware {
  constructor(private readonly responseProvider: ResponseProvider) {}

  use(req: Request, res: Response, next: NextFunction) {
    this.responseProvider.setResponse(res);
    next();
  }
}

Apply Middleware in Module

import { Module, MiddlewareConsumer, NestModule, RequestMethod } from '@nestjs/common';
import { AuthService } from './auth.service'; // Adjust the import
import { AuthController } from './auth.controller'; // Adjust the import
import { ResponseProvider } from './response.provider'; // Adjust the import
import { ResponseMiddleware } from './response.middleware'; // Adjust the import

@Module({
  providers: [AuthService, ResponseProvider],
  controllers: [AuthController],
})
export class AuthModule implements NestModule {
  configure(consumer: MiddlewareConsumer) {
    consumer
      .apply(ResponseMiddleware)
      .forRoutes({ path: '*', method: RequestMethod.ALL });
  }
}

Access Response in AuthService

import { Injectable } from '@nestjs/common';
import { ResponseProvider } from './response.provider'; // Adjust the import
import { LoginDto } from './login.dto'; // Adjust the import

@Injectable()
export class AuthService {
  constructor(private readonly responseProvider: ResponseProvider) {}

  async login(body: LoginDto) {
    const res = this.responseProvider.getResponse();
    // Use the res object as needed
  }
}

Controller

import { Controller, Post, Body } from '@nestjs/common';
import { AuthService } from './auth.service'; // Adjust the import
import { LoginDto } from './login.dto'; // Adjust the import
import { ResponseUtil } from './response.util'; // Adjust the import

@Controller('auth')
export class AuthController {
  constructor(private readonly authService: AuthService) {}

  @Post('/login')
  async login(@Res() res: Response, @Body() body: LoginDto) {
    try {
      const user = await this.authService.login(body);
      return ResponseUtil.success(res, user, 'nice');
    } catch (error) {
      return ResponseUtil.serverError(res, error.stack);
    }
  }
}

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Javascript – Use Response object in service Nestjs