[사이드프로젝트] 그저 그런 REST API로 괜찮은가? - 진정한 REST API 구현해보기 - Event Controller & Event Exception Handler

EventController Test 만들기

테스트 케이스는 다음과 같다.

• 정상적인 EventDto를 보냈을 때 DB에 insert되서 id 값을 담은 Event를 반환하는가
• 잘못된 EventDto를 보냈을 때 Error Code가 반환되는가.

고려 사항

• mockMvc에 content를 담을 때, Json 형식으로 담는다 - objectMapper 활용
• Error Code는 Interceptor를 활용해서 반환한다.
• 현재 Service Layer가 없다 - 임시로 Repository를 컨트롤러 쪽에서 사용한다.

package com.carrykim.restapi.event;

import com.carrykim.restapi.event.model.dto.EventDto;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.hateoas.MediaTypes;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.test.web.servlet.MockMvc;

import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
import static org.springframework.test.web.servlet.result.MockMvcResultHandlers.print;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;

@SpringBootTest
@AutoConfigureMockMvc
public class EventControllerTest {

    @Autowired
    private MockMvc mockMvc;

    @Autowired
    private ObjectMapper objectMapper;


    private EventDto createEventDto(){
        return EventDto.builder()
                .name("My Event")
                .description("This is my first Event")
                .build();
    }

    @Test
    public void create_event_success() throws Exception {
        //Given
        EventDto eventDto = createEventDto();

        //When
        //Then
        mockMvc.perform(post("/api/events")
                        .contentType(MediaType.APPLICATION_JSON)
                        .accept(MediaTypes.HAL_JSON)
                        .content(objectMapper.writeValueAsString(eventDto)))
                .andDo(print())
                .andExpect(status().isCreated())
                .andExpect(jsonPath("id").exists())
                .andExpect(header().exists(HttpHeaders.LOCATION))
                .andExpect(header().string(HttpHeaders.CONTENT_TYPE,MediaTypes.HAL_JSON_VALUE));
    }

    @Test
    public void create_event_bad_request_empty_input() throws Exception {
        //Given
        EventDto eventDto = EventDto.builder().build();

        //When
        //Then
        mockMvc.perform(post("/api/events")
                        .contentType(MediaType.APPLICATION_JSON)
                        .content(objectMapper.writeValueAsString(eventDto)))
                .andDo(print())
                .andExpect(status().isBadRequest())
                .andExpect(jsonPath("timestamp").exists())
                .andExpect(jsonPath("status").exists())
                .andExpect(jsonPath("error").exists())
                .andExpect(jsonPath("message").exists());
    }
}

EventController 만들기

package com.carrykim.restapi.event.controller;

import com.carrykim.restapi.event.model.Event;
import com.carrykim.restapi.event.infra.EventRepository;
import com.carrykim.restapi.event.model.dto.EventDto;
import org.springframework.hateoas.MediaTypes;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.validation.Valid;
import java.net.URI;

import static org.springframework.hateoas.server.mvc.WebMvcLinkBuilder.linkTo;
import static org.springframework.hateoas.server.mvc.WebMvcLinkBuilder.methodOn;

@RestController()
@RequestMapping(value = "/api/events", produces = MediaTypes.HAL_JSON_VALUE)
public class EventController {

    private final EventRepository eventRepository;

    public EventController(EventRepository eventRepository) {
        this.eventRepository = eventRepository;
    }

    @PostMapping("")
    public ResponseEntity create(@RequestBody @Valid EventDto eventDto) {
        Event newEvent = this.eventRepository.save(eventDto.toModel());
        URI uri = linkTo(methodOn(EventController.class).create(new EventDto())).slash(newEvent.getId()).toUri();
        return ResponseEntity.created(uri).body(newEvent);
    }
}

ErrorResponse 만들기

• Response에서 자동으로 Json 매칭을 사용하기 위해선 Getter 선언이 필수!
  - Request도 마찬가지 -> Lombok의 Getter 어노테이션 사용

package com.carrykim.restapi.event.global.exception;

import lombok.Builder;
import lombok.Getter;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Component;
import org.springframework.validation.BindingResult;
import org.springframework.validation.FieldError;

import java.time.LocalDateTime;
import java.util.List;
import java.util.stream.Collectors;

@Getter
public class ErrorResponse {

    private final LocalDateTime timestamp = LocalDateTime.now();
    private int status;
    private List<String> message;
    private String error;

    public ErrorResponse(HttpStatus httpStatus , BindingResult bindingResult) {
        this.status = httpStatus.value();
        this.error = httpStatus.name();
        this.message = bindingResult.getFieldErrors().stream()
                .map(e -> {
                    String m = e.getField() + " : " + e.getDefaultMessage();
                    return m;
                })
                .collect(Collectors.toList());
    }

}

EventExceptionHandler 만들기

package com.carrykim.restapi.event.global.exception;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.hateoas.MediaTypes;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;

@RestControllerAdvice
public class EventExceptionHandler {

    @ExceptionHandler(MethodArgumentNotValidException.class)
    public ResponseEntity validationErrorException(final MethodArgumentNotValidException e) throws JsonProcessingException {

        return ResponseEntity
                .status(HttpStatus.BAD_REQUEST)
                .body(new ErrorResponse(HttpStatus.BAD_REQUEST,e.getBindingResult()));
    }
}