BE/src/filters/auth-exception.filter.ts

import {
  ExceptionFilter,
  Catch,
  ArgumentsHost,
  UnauthorizedException,
} from '@nestjs/common';
import { Response } from 'express';

@Catch(UnauthorizedException)
export class AuthExceptionFilter implements ExceptionFilter {
  catch(exception: UnauthorizedException, host: ArgumentsHost) {
    const ctx = host.switchToHttp();
    const response = ctx.getResponse<Response>();

    const status = exception.getStatus();
    const message = exception.message || 'Unauthorized';

    // Check if message matches specific condition
    if (message.toLocaleLowerCase() === 'authentication failed') {
      // Clear cookies
      response.clearCookie('access_token', {
        httpOnly: true,
        secure: true,
        sameSite: 'none',
      });

      response.clearCookie('refresh_token', {
        httpOnly: true,
        secure: true,
        sameSite: 'none',
      });

      // Send custom response
      return response.status(status).json({
        statusCode: status,
        message: 'Authentication failed',
      });
    }

    // If not a match, fallback to default response
    return response.status(status).json({
      statusCode: status,
      message,
    });
  }
}