5. Repository patterns

---

1. ID를 이용해서 특정 게시물을 가져오는 서비스/컨트롤러 만들기

이제 데이터베이스에 접근하여 특정 게시물을 가져올 수 있도록 다음과 같이 작성한다. 이전 코드와 다른 점은 boardRepository를 이용하는 것과 async/await를 사용한다는 것이다. 그리고 async/await를 사용하기 때문에 Promise 객체를 반환하게 된다.

src/boards/boards.service.ts

import { Injectable, NotFoundException } from "@nestjs/common";
import { InjectRepository } from "@nestjs/typeorm";
import { Repository } from "typeorm";
import { BoardStatus } from "./board-status.enum";
import { Board } from "./board.entity";
import { CreateBoardDto } from "./dto/create-board.dto";

@Injectable()
export class BoardsService {
  constructor(
    @InjectRepository(Board) private boardRepository: Repository<Board>
  ) {}

  async getBoardById(id: number): Promise<Board> {
    const found = await this.boardRepository.findOneBy({ id });

    if (!found) {
      throw new NotFoundException(`Can't find Board with id ${id}`);
    }

    return found;
  }
}

컨트롤러도 이에 맞게 작성한다. id는 숫자여야 하므로 ParseIntPipe를 추가한다.

src/boards/boards.controller.ts

import {
  Body,
  Controller,
  Delete,
  Get,
  Param,
  ParseIntPipe,
  Patch,
  Post,
  UsePipes,
  ValidationPipe,
} from "@nestjs/common";
import { BoardStatus } from "./board-status.enum";
import { Board } from "./board.entity";
import { BoardsService } from "./boards.service";
import { CreateBoardDto } from "./dto/create-board.dto";
import { BoardStatusValidationPipe } from "./pipes/board-status-validation.pipe";

@Controller("boards")
export class BoardsController {
  constructor(private boardsService: BoardsService) {}

  @Get("/:id")
  getBoardById(@Param("id", ParseIntPipe) id: number): Promise<Board> {
    return this.boardsService.getBoardById(id);
  }
}

2. 게시물을 생성하는 서비스/컨트롤러 만들기

이번에는 게시물을 생성하는 부분을 처리해 보자.

src/boards/boards.service.tssrc/boards/boards.controller.ts

import { Injectable, NotFoundException } from "@nestjs/common";
import { InjectRepository } from "@nestjs/typeorm";
import { Repository } from "typeorm";
import { BoardStatus } from "./board-status.enum";
import { Board } from "./board.entity";
import { CreateBoardDto } from "./dto/create-board.dto";

@Injectable()
export class BoardsService {
  constructor(
    @InjectRepository(Board) private boardRepository: Repository<Board>
  ) {}

  async createBoard(createBoardDto: CreateBoardDto): Promise<Board> {
    const { title, description } = createBoardDto;
    const board = this.boardRepository.create({
      title,
      description,
      status: BoardStatus.PUBLIC,
    });

    await this.boardRepository.save(board);
    return board;
  }

  async getBoardById(id: number): Promise<Board> {
    const found = await this.boardRepository.findOneBy({ id });

    if (!found) {
      throw new NotFoundException(`Can't find Board with id ${id}`);
    }

    return found;
  }
}

import {
  Body,
  Controller,
  Delete,
  Get,
  Param,
  ParseIntPipe,
  Patch,
  Post,
  UsePipes,
  ValidationPipe,
} from "@nestjs/common";
import { BoardStatus } from "./board-status.enum";
import { Board } from "./board.entity";
import { BoardsService } from "./boards.service";
import { CreateBoardDto } from "./dto/create-board.dto";
import { BoardStatusValidationPipe } from "./pipes/board-status-validation.pipe";

@Controller("boards")
export class BoardsController {
  constructor(private boardsService: BoardsService) {}

  @Post("/")
  @UsePipes(ValidationPipe)
  createBoard(@Body() createBoardDto: CreateBoardDto): Promise<Board> {
    return this.boardsService.createBoard(createBoardDto);
  }

  @Get("/:id")
  getBoardById(@Param("id", ParseIntPipe) id: number): Promise<Board> {
    return this.boardsService.getBoardById(id);
  }
}

3. 게시물을 삭제하는 서비스/컨트롤러 만들기

게시물을 삭제하는 메서드는 remove()와 delete()가 있다. remove()는 존재하는 아이템을 삭제하며, 존재하지 않는 경우 에러를 발생시킨다. 반대로 delete()는 아이템이 존재하는 경우 삭제하며, 존재하지 않는 경우 어떤 메시지도 발생시키지 않는다.

src/boards/boards.service.tssrc/boards/boards.controller.ts

import { Injectable, NotFoundException } from "@nestjs/common";
import { InjectRepository } from "@nestjs/typeorm";
import { Repository } from "typeorm";
import { BoardStatus } from "./board-status.enum";
import { Board } from "./board.entity";
import { CreateBoardDto } from "./dto/create-board.dto";

@Injectable()
export class BoardsService {
  constructor(
    @InjectRepository(Board) private boardRepository: Repository<Board>
  ) {}

  async createBoard(createBoardDto: CreateBoardDto): Promise<Board> {
    const { title, description } = createBoardDto;
    const board = this.boardRepository.create({
      title,
      description,
      status: BoardStatus.PUBLIC,
    });

    await this.boardRepository.save(board);
    return board;
  }

  async getBoardById(id: number): Promise<Board> {
    const found = await this.boardRepository.findOneBy({ id });

    if (!found) {
      throw new NotFoundException(`Can't find Board with id ${id}`);
    }

    return found;
  }

  async deleteBoard(id: number): Promise<void> {
    const result = await this.boardRepository.delete(id);

    if (result.affected === 0) {
      throw new NotFoundException(`Can't find Board with id ${id}`);
    }
  }
}

import {
  Body,
  Controller,
  Delete,
  Get,
  Param,
  ParseIntPipe,
  Patch,
  Post,
  UsePipes,
  ValidationPipe,
} from "@nestjs/common";
import { BoardStatus } from "./board-status.enum";
import { Board } from "./board.entity";
import { BoardsService } from "./boards.service";
import { CreateBoardDto } from "./dto/create-board.dto";
import { BoardStatusValidationPipe } from "./pipes/board-status-validation.pipe";

@Controller("boards")
export class BoardsController {
  constructor(private boardsService: BoardsService) {}

  @Post("/")
  @UsePipes(ValidationPipe)
  createBoard(@Body() createBoardDto: CreateBoardDto): Promise<Board> {
    return this.boardsService.createBoard(createBoardDto);
  }

  @Get("/:id")
  getBoardById(@Param("id", ParseIntPipe) id: number): Promise<Board> {
    return this.boardsService.getBoardById(id);
  }

  @Delete("/:id")
  deleteBoard(@Param("id", ParseIntPipe) id: number): Promise<void> {
    return this.boardsService.deleteBoard(id);
  }
}

4. 게시물의 상태를 업데이트하는 서비스/컨트롤러 만들기

이번에는 게시물의 상태를 업데이트하는 부분을 처리해 보자.

src/boards/boards.service.tssrc/boards/boards.controller.ts

import { Injectable, NotFoundException } from "@nestjs/common";
import { InjectRepository } from "@nestjs/typeorm";
import { Repository } from "typeorm";
import { BoardStatus } from "./board-status.enum";
import { Board } from "./board.entity";
import { CreateBoardDto } from "./dto/create-board.dto";

@Injectable()
export class BoardsService {
  constructor(
    @InjectRepository(Board) private boardRepository: Repository<Board>
  ) {}

  async createBoard(createBoardDto: CreateBoardDto): Promise<Board> {
    const { title, description } = createBoardDto;
    const board = this.boardRepository.create({
      title,
      description,
      status: BoardStatus.PUBLIC,
    });

    await this.boardRepository.save(board);
    return board;
  }

  async getBoardById(id: number): Promise<Board> {
    const found = await this.boardRepository.findOneBy({ id });

    if (!found) {
      throw new NotFoundException(`Can't find Board with id ${id}`);
    }

    return found;
  }

  async deleteBoard(id: number): Promise<void> {
    const result = await this.boardRepository.delete(id);

    if (result.affected === 0) {
      throw new NotFoundException(`Can't find Board with id ${id}`);
    }
  }

  async updateBoardStatus(id: number, status: BoardStatus): Promise<Board> {
    const board = await this.getBoardById(id);

    board.status = status;
    await this.boardRepository.save(board);

    return board;
  }
}

import {
  Body,
  Controller,
  Delete,
  Get,
  Param,
  ParseIntPipe,
  Patch,
  Post,
  UsePipes,
  ValidationPipe,
} from "@nestjs/common";
import { BoardStatus } from "./board-status.enum";
import { Board } from "./board.entity";
import { BoardsService } from "./boards.service";
import { CreateBoardDto } from "./dto/create-board.dto";
import { BoardStatusValidationPipe } from "./pipes/board-status-validation.pipe";

@Controller("boards")
export class BoardsController {
  constructor(private boardsService: BoardsService) {}

  @Post("/")
  @UsePipes(ValidationPipe)
  createBoard(@Body() createBoardDto: CreateBoardDto): Promise<Board> {
    return this.boardsService.createBoard(createBoardDto);
  }

  @Get("/:id")
  getBoardById(@Param("id", ParseIntPipe) id: number): Promise<Board> {
    return this.boardsService.getBoardById(id);
  }

  @Delete("/:id")
  deleteBoard(@Param("id", ParseIntPipe) id: number): Promise<void> {
    return this.boardsService.deleteBoard(id);
  }

  @Patch("/:id/status")
  updateBoardStatus(
    @Param("id", ParseIntPipe) id: number,
    @Body("status", BoardStatusValidationPipe) status: BoardStatus
  ): Promise<Board> {
    return this.boardsService.updateBoardStatus(id, status);
  }
}

5. 모든 게시물을 가져오는 서비스/컨트롤러 만들기

이번에는 모든 게시물을 가져오는 부분을 처리해 보자.

src/boards/boards.service.tssrc/boards/boards.controller.ts

import { Injectable, NotFoundException } from "@nestjs/common";
import { InjectRepository } from "@nestjs/typeorm";
import { Repository } from "typeorm";
import { BoardStatus } from "./board-status.enum";
import { Board } from "./board.entity";
import { CreateBoardDto } from "./dto/create-board.dto";

@Injectable()
export class BoardsService {
  constructor(
    @InjectRepository(Board) private boardRepository: Repository<Board>
  ) {}

  async getAllBoards(): Promise<Board[]> {
    const boards = await this.boardRepository.find();

    return boards;
  }

  async createBoard(createBoardDto: CreateBoardDto): Promise<Board> {
    const { title, description } = createBoardDto;
    const board = this.boardRepository.create({
      title,
      description,
      status: BoardStatus.PUBLIC,
    });

    await this.boardRepository.save(board);
    return board;
  }

  async getBoardById(id: number): Promise<Board> {
    const found = await this.boardRepository.findOneBy({ id });

    if (!found) {
      throw new NotFoundException(`Can't find Board with id ${id}`);
    }

    return found;
  }

  async deleteBoard(id: number): Promise<void> {
    const result = await this.boardRepository.delete(id);

    if (result.affected === 0) {
      throw new NotFoundException(`Can't find Board with id ${id}`);
    }
  }

  async updateBoardStatus(id: number, status: BoardStatus): Promise<Board> {
    const board = await this.getBoardById(id);

    board.status = status;
    await this.boardRepository.save(board);

    return board;
  }
}

import {
  Body,
  Controller,
  Delete,
  Get,
  Param,
  ParseIntPipe,
  Patch,
  Post,
  UsePipes,
  ValidationPipe,
} from "@nestjs/common";
import { BoardStatus } from "./board-status.enum";
import { Board } from "./board.entity";
import { BoardsService } from "./boards.service";
import { CreateBoardDto } from "./dto/create-board.dto";
import { BoardStatusValidationPipe } from "./pipes/board-status-validation.pipe";

@Controller("boards")
export class BoardsController {
  constructor(private boardsService: BoardsService) {}

  @Get("/")
  getAllBoards(): Promise<Board[]> {
    return this.boardsService.getAllBoards();
  }

  @Post("/")
  @UsePipes(ValidationPipe)
  createBoard(@Body() createBoardDto: CreateBoardDto): Promise<Board> {
    return this.boardsService.createBoard(createBoardDto);
  }

  @Get("/:id")
  getBoardById(@Param("id", ParseIntPipe) id: number): Promise<Board> {
    return this.boardsService.getBoardById(id);
  }

  @Delete("/:id")
  deleteBoard(@Param("id", ParseIntPipe) id: number): Promise<void> {
    return this.boardsService.deleteBoard(id);
  }

  @Patch("/:id/status")
  updateBoardStatus(
    @Param("id", ParseIntPipe) id: number,
    @Body("status", BoardStatusValidationPipe) status: BoardStatus
  ): Promise<Board> {
    return this.boardsService.updateBoardStatus(id, status);
  }
}

---

References

• https://www.youtube.com/watch?v=3JminDpCJNE