feat: 카카오 oauth 로그인

src/main/java/com/j9/bestmoments/controller/AuthController.java

@@ -3,6 +3,7 @@
 import com.j9.bestmoments.dto.response.LoginDto;
 import com.j9.bestmoments.dto.response.OAuthUserInfoDto;
 import com.j9.bestmoments.service.GoogleAuthService;
+import com.j9.bestmoments.service.KakaoAuthService;
 import com.j9.bestmoments.service.OAuthService;
 import com.j9.bestmoments.domain.Member;
 import com.j9.bestmoments.service.MemberService;
@@ -28,6 +29,7 @@
 public class AuthController {
 
     private final GoogleAuthService googleAuthService;
+    private final KakaoAuthService kakaoAuthService;
     private final MemberService memberService;
     private final TokenService tokenService;
 
@@ -36,6 +38,7 @@ public class AuthController {
     public ResponseEntity<LoginDto> login(@PathVariable String registrationId, @RequestParam String code) {
         OAuthService oAuthService = switch (registrationId) {
             case "google" -> googleAuthService;
+            case "kakao" -> kakaoAuthService;
             default -> throw new OAuth2AuthenticationException("존재하지 않는 OAuth 인증 방식입니다.");
         };
         OAuthUserInfoDto oAuthUserInfo = oAuthService.getUserInfo(code);

src/main/java/com/j9/bestmoments/service/KakaoAuthService.java

@@ -0,0 +1,74 @@
+package com.j9.bestmoments.service;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.j9.bestmoments.dto.response.OAuthUserInfoDto;
+import java.util.Collections;
+import java.util.Map;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.http.HttpEntity;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Service;
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
+import org.springframework.web.client.RestTemplate;
+
+@Service
+public class KakaoAuthService implements OAuthService {
+
+    @Value("${oauth2.kakao.client-id}")
+    private String clientId;
+
+    @Value("${oauth2.kakao.redirect-uri}")
+    private String redirectUri;
+
+    @Value("${oauth2.kakao.token-uri}")
+    private String tokenUri;
+
+    @Value("${oauth2.kakao.userinfo-uri}")
+    private String userinfoUrl;
+
+    @Override
+    public OAuthUserInfoDto getUserInfo(String code) {
+        String accessToken = getAccessToken(code);
+        Map attributes = getUserInfoAttributes(accessToken);
+        Map kakao_account = (Map) attributes.get("kakao_account");
+        Map profile = (Map) kakao_account.get("profile");
+        return OAuthUserInfoDto.builder()
+                .provider("kakao")
+                .id(attributes.get("id").toString())
+                .name(profile.get("nickname").toString())
+                .email(kakao_account.get("email").toString())
+                .build();
+    }
+
+    private String getAccessToken(String code) {
+        MultiValueMap<String, String> params = new LinkedMultiValueMap<>();
+        params.put("grant_type", Collections.singletonList("authorization_code"));
+        params.put("client_id", Collections.singletonList(clientId));
+        params.put("redirect_uri", Collections.singletonList(redirectUri));
+        params.put("code", Collections.singletonList(code));
+
+        HttpHeaders headers = new HttpHeaders();
+        headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
+
+        HttpEntity entity = new HttpEntity(params, headers);
+
+        RestTemplate restTemplate = new RestTemplate();
+        ResponseEntity<JsonNode> responseNode = restTemplate.exchange(tokenUri, HttpMethod.POST, entity, JsonNode.class);
+        JsonNode accessTokenNode = responseNode.getBody();
+
+        return accessTokenNode.get("access_token").asText();
+    }
+
+    private Map getUserInfoAttributes(String accessToken) {
+        HttpHeaders headers = new HttpHeaders();
+        headers.setBearerAuth(accessToken);
+        HttpEntity<String> entity = new HttpEntity<>(headers);
+        RestTemplate restTemplate = new RestTemplate();
+        return restTemplate.exchange(userinfoUrl, HttpMethod.GET, entity, Map.class).getBody();
+    }
+
+}