make API more robust

Signed-off-by: Peter Siegmund <developer@mars3142.org>

src/main/java/dev/mars3142/fhq/timezone_service/config/AppConfig.java

@@ -1,14 +1,23 @@
 package dev.mars3142.fhq.timezone_service.config;
 
+import org.springframework.cache.CacheManager;
+import org.springframework.cache.annotation.EnableCaching;
+import org.springframework.cache.concurrent.ConcurrentMapCacheManager;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.web.client.RestClient;
 
 @Configuration
+@EnableCaching
 public class AppConfig {
 
   @Bean
   public RestClient restClient() {
     return RestClient.create();
   }
+
+  @Bean
+  public CacheManager cacheManager() {
+    return new ConcurrentMapCacheManager();
+  }
 }

src/main/java/dev/mars3142/fhq/timezone_service/timezone/domain/entities/response/IpifyResponse.java

@@ -0,0 +1,5 @@
+package dev.mars3142.fhq.timezone_service.timezone.domain.entities.response;
+
+public record IpifyResponse(String ip) {
+
+}

src/main/java/dev/mars3142/fhq/timezone_service/timezone/domain/entities/response/WorldTimeApiIpResponse.java

@@ -1,7 +1,9 @@
 package dev.mars3142.fhq.timezone_service.timezone.domain.entities.response;
 
-public record WorldTimeApiIpResponse(String utc_offset, String timezone, int day_of_week, int day_of_year, String datetime,
+public record WorldTimeApiIpResponse(String utc_offset, String timezone, int day_of_week, int day_of_year,
+                                     String datetime,
                                      String utc_datetime, int unixtime, int raw_offset, int week_number, boolean dst,
-                                     String abbreviation, int dst_offset, String dst_from, String dst_until, String client_ip) {
+                                     String abbreviation, int dst_offset, String dst_from, String dst_until,
+                                     String client_ip) {
 
 }

src/main/java/dev/mars3142/fhq/timezone_service/timezone/service/TimeZoneService.java

@@ -6,7 +6,9 @@ import java.util.List;
 
 public interface TimeZoneService {
 
-  WorldTimeApiIpResponse getTimeZoneInfoByIp();
+  String getExternalIp(String ip);
+
+  WorldTimeApiIpResponse getTimeZoneInfoByIp(String ip);
 
   TimeApiTimezoneZoneResponse getTimeZoneInfo(String timezone);
 

src/main/java/dev/mars3142/fhq/timezone_service/timezone/service/impl/TimeZoneServiceImpl.java

@@ -1,6 +1,7 @@
 package dev.mars3142.fhq.timezone_service.timezone.service.impl;
 
 import dev.mars3142.fhq.timezone_service.exceptions.NotFoundException;
+import dev.mars3142.fhq.timezone_service.timezone.domain.entities.response.IpifyResponse;
 import dev.mars3142.fhq.timezone_service.timezone.domain.entities.response.TimeApiTimezoneZoneResponse;
 import dev.mars3142.fhq.timezone_service.timezone.domain.entities.response.WorldTimeApiIpResponse;
 import dev.mars3142.fhq.timezone_service.timezone.service.TimeZoneService;
@@ -13,6 +14,7 @@ import java.util.Objects;
 import java.util.stream.Stream;
 import lombok.RequiredArgsConstructor;
 import lombok.val;
+import org.springframework.cache.annotation.Cacheable;
 import org.springframework.http.HttpStatusCode;
 import org.springframework.stereotype.Service;
 import org.springframework.web.client.RestClient;
@@ -24,15 +26,30 @@ public class TimeZoneServiceImpl implements TimeZoneService {
   private final RestClient restClient;
 
   @Override
-  public WorldTimeApiIpResponse getTimeZoneInfoByIp() {
+  public String getExternalIp(String ip) {
+    if (ip.equals("127.0.0.1")) {
+      val response = restClient
+          .get()
+          .uri("https://api.ipify.org?format=json")
+          .retrieve()
+          .body(IpifyResponse.class);
+      return Objects.requireNonNull(response).ip();
+    }
+    return ip;
+  }
+
+  @Override
+  @Cacheable(value = "TZInfoByIp", key = "{#ip}")
+  public WorldTimeApiIpResponse getTimeZoneInfoByIp(String ip) {
     return restClient
         .get()
-        .uri("https://worldtimeapi.org/api/ip")
+        .uri("https://worldtimeapi.org/api/ip/" + ip)
         .retrieve()
         .body(WorldTimeApiIpResponse.class);
   }
 
   @Override
+  @Cacheable(value = "TZInfo", key = "{#timezone}")
   public TimeApiTimezoneZoneResponse getTimeZoneInfo(String timezone) {
     return restClient
         .get()
@@ -50,6 +67,7 @@ public class TimeZoneServiceImpl implements TimeZoneService {
   }
 
   @Override
+  @Cacheable(value = "posixTZ", key = "{#timezone}")
   public String getPosixTimeZone(String timezone) {
     val filename = Path.of("/usr/share/zoneinfo/" + timezone);
     if (!filename.toFile().exists()) {
@@ -65,6 +83,7 @@ public class TimeZoneServiceImpl implements TimeZoneService {
   }
 
   @Override
+  @Cacheable(value = "locations", key = "{#area}")
   public List<String> getLocations(String area) {
     val directory = new File("/usr/share/zoneinfo/" + area);
     if (!directory.exists()) {

src/main/java/dev/mars3142/fhq/timezone_service/timezone/web/controllers/TimeZoneController.java

@@ -3,6 +3,7 @@ package dev.mars3142.fhq.timezone_service.timezone.web.controllers;
 import dev.mars3142.fhq.timezone_service.timezone.domain.model.response.LocationResponse;
 import dev.mars3142.fhq.timezone_service.timezone.domain.model.response.TimeZoneResponse;
 import dev.mars3142.fhq.timezone_service.timezone.service.TimeZoneService;
+import jakarta.servlet.http.HttpServletRequest;
 import lombok.RequiredArgsConstructor;
 import lombok.val;
 import org.springframework.web.bind.annotation.GetMapping;
@@ -18,8 +19,9 @@ public class TimeZoneController {
   private final TimeZoneService timeZoneService;
 
   @GetMapping
-  public TimeZoneResponse getTimeZone() {
-    val timezoneInfo = timeZoneService.getTimeZoneInfoByIp();
+  public TimeZoneResponse getTimeZone(HttpServletRequest request) {
+    val ip = timeZoneService.getExternalIp(request.getRemoteAddr());
+    val timezoneInfo = timeZoneService.getTimeZoneInfoByIp(ip);
     val posix = timeZoneService.getPosixTimeZone(timezoneInfo.timezone());
     return new TimeZoneResponse(timezoneInfo.timezone(), timezoneInfo.abbreviation(), posix);
   }