NestJS Interceptors

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

@Injectable()
export class LoggingInterceptor implements NestInterceptor {
  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
    const request = context.switchToHttp().getRequest();
    const start = Date.now();

    console.log("➡️", request.method, request.url);

    return next.handle().pipe(
      tap(() =>
        console.log("⬅️", request.method, request.url, Date.now() - start + "ms"),
      ),
    );
  }
}

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

export interface Response<T> {
  success: boolean;
  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) => ({
        success: true,
        data,
      })),
    );
  }
}

// সব response:
// { success: true, data: ... }

import { Injectable, NestInterceptor, RequestTimeoutException } from "@nestjs/common";
import { Observable, TimeoutError, throwError } from "rxjs";
import { catchError, timeout } from "rxjs/operators";

@Injectable()
export class TimeoutInterceptor implements NestInterceptor {
  intercept(context, next): Observable<any> {
    return next.handle().pipe(
      timeout(10000), // 10s পর request timeout
      catchError((err) => {
        if (err instanceof TimeoutError) {
          return throwError(() => new RequestTimeoutException());
        }
        return throwError(() => err);
      }),
    );
  }
}

import { UseInterceptors, Post, Controller } from "@nestjs/common";
import { LoggingInterceptor } from "../common/logging.interceptor";

// controller-লেভেল
@UseInterceptors(LoggingInterceptor)
@Controller("users")
export class UsersController {}

// method-লেভেল
@Post()
@UseInterceptors(new LoggingInterceptor())
create() {}

// global
app.useGlobalInterceptors(new TransformInterceptor());