Json 저장

라이브러리 추가

// https://mvnrepository.com/artifact/com.google.firebase/firebase-admin
implementation 'com.google.firebase:firebase-admin:8.1.0'
// https://mvnrepository.com/artifact/org.modelmapper/modelmapper
implementation 'org.modelmapper:modelmapper:2.4.4'

설정파일

import com.google.auth.oauth2.GoogleCredentials;
import com.google.firebase.FirebaseApp;
import com.google.firebase.FirebaseOptions;
import org.springframework.context.annotation.Configuration;
import javax.annotation.PostConstruct;
import java.io.FileInputStream;

@Configuration
public class FirebaseConfig {
    private final String path = "src/main/resources/firebase/firebaseAccountKey.json";

    @PostConstruct
    public void init(){
        try{
            FirebaseOptions options = new FirebaseOptions.Builder()
                    .setCredentials(GoogleCredentials.fromStream(new FileInputStream(path))).build();
            if (FirebaseApp.getApps().isEmpty()) {
                FirebaseApp.initializeApp(options);
            }
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

구현

1. 토큰 값 가져오기

public String getAccessToken() throws IOException {
        FileInputStream inputStream = new FileInputStream("src/main/resources/firebase/firebaseAccountKey.json");
        GoogleCredentials googleCredentials = GoogleCredentials
                .fromStream(inputStream)
                .createScoped(List.of("https://www.googleapis.com/auth/cloud-platform"));
        googleCredentials.refreshIfExpired();
        return googleCredentials.getAccessToken().getTokenValue();
    }

2. 메시지 생성

private String makeMessage(String token, String title, String body) throws JsonProcessingException {
        FcmMessage fcmMessage = FcmMessage.builder()
                .message(FcmMessage.Message.builder()
                        .token(token)
                        .notification(FcmMessage.Notification.builder()
                                .title(title)
                                .body(body)
                                .image(null)
                                .build())
                        .build())
                .validate_only(false)
                .build();
        return objectMapper.writeValueAsString(fcmMessage);
    }

FcmMessage

@AllArgsConstructor
@Builder
@Data
public class FcmMessage {
    private boolean validate_only;
    private Message message;

    @AllArgsConstructor
    @Builder
    @Data
    public static class Message {
        private Notification notification;
        private String token;
    }

    @AllArgsConstructor
    @Builder
    @Data
    public static class Notification {
        private String title;
        private String body;
        private String image;
    }
}

3. 메시지 전송

public void sendMessageTo(String token, String title, String body) throws IOException {
        String message = makeMessage(token, title, body);
        OkHttpClient client = new OkHttpClient();
        RequestBody requestBody = RequestBody.create(MediaType.get("application/json; charset=utf-8"), message);

        Request request = new Request.Builder()
                .url(API_URL)
                .post(requestBody)
                .addHeader(HttpHeaders.AUTHORIZATION, "Bearer " + getAccessToken())
                .addHeader(HttpHeaders.CONTENT_TYPE, "application/json; UTF-8")
                .build();

        Response response = client.newCall(request)
                .execute();

        log.info(response.body().toString());
    }

---

서비스로 등록

특정유저에게 전송해야 할 경우가 많으니 귀찮으니까 빈으로 등록하자

@Slf4j
@RequiredArgsConstructor
@Service
public class FcmSendService {
    private final FirebaseCloudMessageService fcmService;
    private final UserTokenService userTokenService;
    private final UserNotificationService userNotificationService;

    public void sendFCM(User user,String title,String body) throws Exception {
        byte[] decode = Base64.getDecoder().decode(userTokenService.findTokenByUserIdAndType(user.getId(), "fcm"));
        String token = new String(decode, StandardCharsets.UTF_8);
        fcmService.sendMessageTo(token,title,body);
        userNotificationService.save(new UserNotification(title, body, user));
    }
}