feat: 기상청 초단기실황 API 연동 서비스 구현

Author: howooyeon

src/main/java/com/semosan/api/common/config/WebClientConfig.java

@@ -21,4 +21,11 @@ public WebClient appleApiWebClient() {
                 .build();
     }
 
+    @Bean
+    public WebClient weatherApiWebClient() {
+        return WebClient.builder()
+                .baseUrl("https://apis.data.go.kr/1360000/VilageFcstInfoService_2.0")
+                .build();
+    }
+
 }

src/main/java/com/semosan/api/common/util/GridConverter.java

@@ -0,0 +1,48 @@
+package com.semosan.api.common.util;
+
+public class GridConverter {
+
+    private static final double RE = 6371.00877;
+    private static final double GRID = 5.0;
+    private static final double SLAT1 = 30.0;
+    private static final double SLAT2 = 60.0;
+    private static final double OLON = 126.0;
+    private static final double OLAT = 38.0;
+    private static final double XO = 43;
+    private static final double YO = 136;
+
+    private GridConverter() {
+    }
+
+    public record Grid(int nx, int ny) {
+    }
+
+    public static Grid toGrid(double lat, double lon) {
+        double degrad = Math.PI / 180.0;
+
+        double re = RE / GRID;
+        double slat1 = SLAT1 * degrad;
+        double slat2 = SLAT2 * degrad;
+        double olon = OLON * degrad;
+        double olat = OLAT * degrad;
+
+        double sn = Math.tan(Math.PI * 0.25 + slat2 * 0.5) / Math.tan(Math.PI * 0.25 + slat1 * 0.5);
+        sn = Math.log(Math.cos(slat1) / Math.cos(slat2)) / Math.log(sn);
+        double sf = Math.tan(Math.PI * 0.25 + slat1 * 0.5);
+        sf = Math.pow(sf, sn) * Math.cos(slat1) / sn;
+        double ro = Math.tan(Math.PI * 0.25 + olat * 0.5);
+        ro = re * sf / Math.pow(ro, sn);
+
+        double ra = Math.tan(Math.PI * 0.25 + lat * degrad * 0.5);
+        ra = re * sf / Math.pow(ra, sn);
+        double theta = lon * degrad - olon;
+        if (theta > Math.PI) theta -= 2.0 * Math.PI;
+        if (theta < -Math.PI) theta += 2.0 * Math.PI;
+        theta *= sn;
+
+        int nx = (int) Math.floor(ra * Math.sin(theta) + XO + 0.5);
+        int ny = (int) Math.floor(ro - ra * Math.cos(theta) + YO + 0.5);
+
+        return new Grid(nx, ny);
+    }
+}

src/main/java/com/semosan/api/common/weather/WeatherService.java

@@ -0,0 +1,94 @@
+package com.semosan.api.common.weather;
+
+import com.semosan.api.common.util.GridConverter;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Service;
+import org.springframework.web.reactive.function.client.WebClient;
+
+import java.time.Duration;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+
+@Slf4j
+@Service
+public class WeatherService {
+
+    private static final DateTimeFormatter DATE_FMT = DateTimeFormatter.ofPattern("yyyyMMdd");
+    private static final DateTimeFormatter TIME_FMT = DateTimeFormatter.ofPattern("HHmm");
+
+    private final WebClient webClient;
+    private final String apiKey;
+
+    public WeatherService(
+            @Qualifier("weatherApiWebClient") WebClient webClient,
+            @Value("${weather.api-key}") String apiKey
+    ) {
+        this.webClient = webClient;
+        this.apiKey = apiKey;
+    }
+
+    public Optional<Double> getTemperature(double latitude, double longitude) {
+        try {
+            GridConverter.Grid grid = GridConverter.toGrid(latitude, longitude);
+            LocalDateTime now = adjustBaseTime(LocalDateTime.now());
+
+            String baseDate = now.format(DATE_FMT);
+            String baseTime = now.format(TIME_FMT);
+
+            Map<String, Object> response = webClient.get()
+                    .uri(uriBuilder -> uriBuilder
+                            .path("/getUltraSrtNcst")
+                            .queryParam("serviceKey", apiKey)
+                            .queryParam("pageNo", 1)
+                            .queryParam("numOfRows", 10)
+                            .queryParam("dataType", "JSON")
+                            .queryParam("base_date", baseDate)
+                            .queryParam("base_time", baseTime)
+                            .queryParam("nx", grid.nx())
+                            .queryParam("ny", grid.ny())
+                            .build())
+                    .retrieve()
+                    .bodyToMono(Map.class)
+                    .block(Duration.ofSeconds(3));
+
+            return extractTemperature(response);
+        } catch (Exception e) {
+            log.warn("기상청 API 호출 실패: {}", e.getMessage());
+            return Optional.empty();
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    private Optional<Double> extractTemperature(Map<String, Object> response) {
+        if (response == null) return Optional.empty();
+
+        Map<String, Object> root = (Map<String, Object>) response.get("response");
+        if (root == null) return Optional.empty();
+
+        Map<String, Object> body = (Map<String, Object>) root.get("body");
+        if (body == null) return Optional.empty();
+
+        Map<String, Object> items = (Map<String, Object>) body.get("items");
+        if (items == null) return Optional.empty();
+
+        List<Map<String, Object>> itemList = (List<Map<String, Object>>) items.get("item");
+        if (itemList == null) return Optional.empty();
+
+        return itemList.stream()
+                .filter(item -> "T1H".equals(item.get("category")))
+                .findFirst()
+                .map(item -> Double.parseDouble(String.valueOf(item.get("obsrValue"))));
+    }
+
+    private LocalDateTime adjustBaseTime(LocalDateTime now) {
+        if (now.getMinute() < 40) {
+            now = now.minusHours(1);
+        }
+        return now.withMinute(0).withSecond(0).withNano(0);
+    }
+}

src/main/resources/application.yaml

@@ -79,6 +79,9 @@ management:
       export:
         enabled: true
 
+weather:
+  api-key: ${WEATHER_API_KEY}
+
 discord:
   alert:
     enabled: ${DISCORD_ALERT_ENABLED}