find-user-by-email.http.controller.ts

import { Controller, Get, Param } from '@nestjs/common';
import { routes } from '@config/app.routes';
import { UserResponse } from '@modules/user/dtos/user.response.dto';
import { UserRepository } from '@modules/user/database/user.repository';

@Controller()
export class FindUserByEmailHttpController {
  constructor(private readonly userRepo: UserRepository) {}

  /* since this is a simple query with no additional business
     logic involved, it bypasses application's core completely 
     and retrieves user directly from repository. Validation of this
     query is also not required since no data is persisted; if 
     email is incorrect "Not found" exception will be returned anyway.
   */
  @Get(routes.user.findByEmail)
  async findByEmail(@Param('email') email: string): Promise<UserResponse> {
    const user = await this.userRepo.findOneByEmailOrThrow(email);

    return new UserResponse(user);
  }
}