Feat: CHAT-254-BE-카카오-로그인 (#41)

* Feat: CHAT-254-BE-카카오-로그인

* Fix: nickname으로 가입/미가입 판별

- Member에 nickname(varchar) 추가
- nickname으로 가입된 사용자인지 판별후
가입 사용자 -> jwt반환
미가입 사용자 -> 회원가입(db에 저장)후 jwt반환

* Fix: findByNickname() 추가

build.gradle

@@ -27,11 +27,16 @@ dependencies {
 	implementation 'org.springframework.boot:spring-boot-starter-web'
 	implementation 'org.springframework.cloud:spring-cloud-starter-aws:2.2.6.RELEASE'
 	implementation 'org.springframework.boot:spring-boot-starter-websocket'
+    implementation 'com.google.code.gson:gson:2.8.8'
 	compileOnly 'org.projectlombok:lombok'
 	annotationProcessor 'org.projectlombok:lombok'
 	testImplementation 'org.springframework.boot:spring-boot-starter-test'
 	runtimeOnly('mysql:mysql-connector-java:8.0.30')
 	runtimeOnly('com.h2database:h2')
+
+	implementation 'io.jsonwebtoken:jjwt-api:0.12.3'
+	runtimeOnly 'io.jsonwebtoken:jjwt-impl:0.12.3'
+	runtimeOnly 'io.jsonwebtoken:jjwt-jackson:0.12.3'
 }
 
 tasks.named('test') {

src/main/java/com/kuit/chatdiary/controller/Login/KakaoLogin.java

@@ -0,0 +1,18 @@
+package com.kuit.chatdiary.controller.Login;
+
+import org.springframework.beans.factory.annotation.Value;
+
+public class KakaoLogin {
+
+    @Value("${KAKAO_API_KEY}")
+    private String kakaoApiKey;
+
+    @Value("${KAKAO_REDIRECT_URI}")
+    private String kakaoRedirectUri;
+
+    @Value("${S3_BUCKET}")
+    private String secretKey;
+
+
+
+}

src/main/java/com/kuit/chatdiary/controller/Login/LogInController.java

@@ -0,0 +1,62 @@
+package com.kuit.chatdiary.controller.Login;
+
+import com.kuit.chatdiary.dto.login.KakaoLoginResponseDTO;
+import com.kuit.chatdiary.service.LogInService;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+
+import java.util.Map;
+
+@Controller
+@RequiredArgsConstructor
+@Slf4j
+public class LogInController {
+
+    @Autowired
+    public LogInService logInService;
+
+
+    @GetMapping("/kakao/callback")
+    public KakaoLoginResponseDTO login(@RequestParam("code") String code) throws Exception {
+        //1. 클라이언트에서 로그인 코드를 보내줌 (서버에서 할일 X)
+        System.out.println("code: "+code);
+
+        //2. 토큰 받기
+        String accessToken = logInService.getAccessToken(code);
+        System.out.println("accessToken: "+accessToken);
+
+        //3. 사용자 정보 받기
+        Map<String, Object> userInfo = logInService.getUserInfo(accessToken);
+        String nickname = (String)userInfo.get("nickname");
+
+        System.out.println("nickname = " + nickname);
+        System.out.println("accessToken = " + accessToken);
+
+        if(nickname == null){
+            throw new Exception("인증되지 않은 사용자입니다");
+        }
+
+        String jwt = logInService.generateJwt(nickname, 3600000);
+        System.out.println("jwt: "+jwt);
+
+        Boolean isMember = logInService.isMember(nickname);
+
+        //가입된 사용자 -> 바로 로그인
+        if(isMember){
+            log.info("가입된 사용자입니다.");
+            return new KakaoLoginResponseDTO(jwt);
+        }else{//미가입 사용자 -> 회원가입&로그인
+            log.info("미가입 사용자입니다.");
+            logInService.saveMember(nickname);
+
+            return new KakaoLoginResponseDTO(jwt);
+        }
+
+
+    }
+
+}

src/main/java/com/kuit/chatdiary/domain/Member.java

@@ -1,10 +1,7 @@
 package com.kuit.chatdiary.domain;
 
 import jakarta.persistence.*;
-import lombok.Builder;
-import lombok.Cleanup;
-import lombok.Getter;
-import lombok.NoArgsConstructor;
+import lombok.*;
 import org.hibernate.annotations.ColumnDefault;
 import org.springframework.data.annotation.CreatedDate;
 import org.springframework.data.annotation.LastModifiedDate;
@@ -16,13 +13,16 @@
 
 @Entity(name = "member")
 @Getter
+@Setter
 @NoArgsConstructor
 @EntityListeners(AuditingEntityListener.class)
 public class Member {
     @Id @GeneratedValue(strategy = GenerationType.IDENTITY) //auto increment
     @Column(name = "user_id")
     private Long userId;
 
+    private String nickname;
+
     private String email;
 
     private String password;

src/main/java/com/kuit/chatdiary/dto/login/KakaoLoginResponseDTO.java

@@ -0,0 +1,14 @@
+package com.kuit.chatdiary.dto.login;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+public class KakaoLoginResponseDTO {
+    private String jwt;
+}

src/main/java/com/kuit/chatdiary/repository/MemberRepository.java

@@ -4,4 +4,5 @@
 import org.springframework.data.jpa.repository.JpaRepository;
 
 public interface MemberRepository extends JpaRepository<Member, Long> {
+    Member findByNickname(String nickname);
 }

src/main/java/com/kuit/chatdiary/service/LogInService.java

@@ -0,0 +1,166 @@
+package com.kuit.chatdiary.service;
+
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParser;
+import com.kuit.chatdiary.domain.Member;
+import com.kuit.chatdiary.repository.MemberRepository;
+import io.jsonwebtoken.Jwts;
+import io.jsonwebtoken.SignatureAlgorithm;
+import io.jsonwebtoken.security.Keys;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Service;
+
+import javax.crypto.SecretKey;
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.util.Date;
+import java.util.HashMap;
+
+@Slf4j
+@Service
+public class LogInService {
+
+    @Autowired
+    private final MemberRepository memberRepository;
+
+    @Value("${KAKAO_API_KEY}")
+    private String kakaoApiKey;
+
+    @Value("${KAKAO_REDIRECT_URI}")
+    private String kakaoRedirectUri;
+
+    public LogInService(MemberRepository memberRepository) {
+        this.memberRepository = memberRepository;
+    }
+
+    // AccessToken 발급하는 메서드
+    public String getAccessToken(String code) {
+        log.info("[KakaoService.getAccessToken]");
+
+        String accessToken = "";
+        String reqUrl = "https://kauth.kakao.com/oauth/token";
+
+        try{
+            URL url = new URL(reqUrl);
+            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
+
+            conn.setRequestMethod("POST");
+            conn.setDoOutput(true);
+
+            BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(conn.getOutputStream()));
+            StringBuilder sb = new StringBuilder();
+
+            sb.append("grant_type=authorization_code");
+            sb.append("&client_id=").append(kakaoApiKey);
+            sb.append("&redirect_uri=").append(kakaoRedirectUri);
+            sb.append("&code=").append(code);
+
+            bw.write(sb.toString());
+            bw.flush();
+
+            BufferedReader br;
+            br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
+
+            String line = "";
+            StringBuilder responseSb = new StringBuilder();
+            while((line = br.readLine()) != null){
+                responseSb.append(line);
+            }
+            String result = responseSb.toString();
+            System.out.println("responseBody : "+result);
+
+            JsonParser parser = new JsonParser();
+            JsonElement element = parser.parse(result);
+            accessToken = element.getAsJsonObject().get("access_token").getAsString();
+
+            br.close();
+            bw.close();
+
+        }catch (Exception e){
+            e.printStackTrace();
+        }
+        return accessToken;
+    }
+
+    // 사용자 정보 가져오는 메서드
+    public HashMap<String, Object> getUserInfo(String accessToken) {
+        HashMap<String, Object> userInfo = new HashMap<>();
+        String reqUrl = "https://kapi.kakao.com/v2/user/me";
+        try{
+            URL url = new URL(reqUrl);
+            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
+            conn.setRequestMethod("POST");
+            conn.setRequestProperty("Authorization", "Bearer " + accessToken);
+
+            BufferedReader br;
+            br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
+
+            String line = "";
+            StringBuilder responseSb = new StringBuilder();
+            while((line = br.readLine()) != null){
+                responseSb.append(line);
+            }
+            String result = responseSb.toString();
+            JsonParser parser = new JsonParser();
+            JsonElement element = parser.parse(result);
+
+            JsonObject properties = element.getAsJsonObject().get("properties").getAsJsonObject();
+            String nickname = properties.getAsJsonObject().get("nickname").getAsString();
+            userInfo.put("nickname", nickname);
+
+            br.close();
+
+        }catch (Exception e){
+            e.printStackTrace();
+        }
+        return userInfo;
+    }
+
+    // jwt 발급하는 메서드
+    public String generateJwt(String nickname, long expirationTime){
+
+        SecretKey secretKey = Keys.secretKeyFor(SignatureAlgorithm.HS256);
+        Date expirationDate = new Date(System.currentTimeMillis() + expirationTime);
+
+        return Jwts.builder()
+                .setSubject(nickname)
+                .setExpiration(expirationDate)
+                .signWith(secretKey, SignatureAlgorithm.HS256)
+                .compact();
+    }
+
+    public Boolean isMember(String nickname) {
+        Member member = memberRepository.findByNickname(nickname);
+        if(member==null){
+            return false;
+        }
+        return true;
+    }
+
+    public void saveMember(String nickname) {
+        //이메일, 패스워드는 막넣음
+        String defaultEmail = nickname+"@"+nickname;
+        String defaultPassword = nickname+"123";
+
+        Member member = new Member();
+        member.setNickname(nickname);
+        member.setEmail(defaultEmail);
+        member.setPassword(defaultPassword);
+
+        memberRepository.save(member);
+
+        if(member.getUserId() !=null){
+            log.info("가입 완료!");
+        }else{
+            log.info("가입 실패!");
+        }
+
+    }
+}