在Nest.js中发送之前如何格式化响应? [英] How to format response before sending in Nest.js?

问题描述

我遵循了文档，并能够添加一个拦截器来进行响应映射.

I followed the documentation and was able to add an interceptor for response mapping.

我想要一致的json格式输出以用于响应.

I want a consistent json format output for responses.

如何使用拦截器或比该方法更好的方法来实现这一目标.

How can I achieve this with interceptor or with something else better than this approach.

{
  "statusCode": 201,
  "message": "Custom Dynamic Message"
  "data": {
     // properties
     meta: {}
  }
}

transform.interceptor.ts

import {
  Injectable,
  NestInterceptor,
  ExecutionContext,
  CallHandler,
} from '@nestjs/common';
import { Observable } from 'rxjs';
import { map } from 'rxjs/operators';

export interface Response<T> {
  statusCode: number;
  data: T;
}

@Injectable()
export class TransformInterceptor<T>
  implements NestInterceptor<T, Response<T>> {
  intercept(
    context: ExecutionContext,
    next: CallHandler,
  ): Observable<Response<T>> {
    return next
      .handle()
      .pipe(
        map((data) => ({
          statusCode: context.switchToHttp().getResponse().statusCode,
          data,
        })),
      );
  }
}

app.controller.ts

export class AppController {
      @Post('login')
      @UseGuards(AuthGuard('local'))
      @ApiOperation({ summary: 'Login user' })
      @ApiBody({ type: LoginDto })
      @ApiOkResponse({ content: { 'application/json': {} } })
      @UseInterceptors(TransformInterceptor)
      async login(@Request() req) {
        const result = await this.authService.login(req.user);
        return { message: 'Thank you!', result };
      }
}

推荐答案

如果我了解您对控制器响应和总体拦截器响应所做的事情，则可以执行以下操作:

If I am understanding what you are doing with your controller response and your overall interceptor response, what you can do is something similar:

import {
  Injectable,
  NestInterceptor,
  ExecutionContext,
  CallHandler,
} from '@nestjs/common';
import { Observable } from 'rxjs';
import { map } from 'rxjs/operators';

export interface Response<T> {
  statusCode: number;
  message: string;
  data: T;
}

@Injectable()
export class TransformInterceptor<T>
  implements NestInterceptor<T, Response<T>> {
  intercept(
    context: ExecutionContext,
    next: CallHandler,
  ): Observable<Response<T>> {
    return next
      .handle()
      .pipe(
        map((data) => ({
          statusCode: context.switchToHttp().getResponse().statusCode,
          message: data.message
          data: {
            result: data.result,
            meta: {} // if this is supposed to be the actual return then replace {} with data.result
          }
        })),
      );
  }
}

并使您的控制器返回为 {message:'Custom message'，result} .

And keep your controller return as {message: 'Custom message', result}.

另一个需要更多前期准备但可能允许使用更简洁代码的选项是创建一个自定义装饰器，该装饰器从类和方法中反映一个值(消息)，然后在注入反射器后在拦截器中检索该值，但是再次，这将需要更多的前期工作来建立.

Another option, which would require more upfront but possible allow for cleaner code would be to create a custom decorator that reflected a value (message) from the class and method and then retrieved that value in the interceptor after injecting the reflector, but again, that would take more upfront effort to set up.

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