#74 add a rest-endpoint (with caching) for dailyImages

src/main/java/ch/akop/homesystem/HomeSystemApplication.java

@@ -5,11 +5,13 @@
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.context.properties.ConfigurationPropertiesScan;
 import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
+import org.springframework.scheduling.annotation.EnableAsync;
 import org.springframework.scheduling.annotation.EnableScheduling;
 
 @SpringBootApplication
 @EnableJpaRepositories
 @EnableScheduling
+@EnableAsync
 @ConfigurationPropertiesScan("ch.akop.homesystem.config.properties")
 public class HomeSystemApplication {
 

src/main/java/ch/akop/homesystem/controller/ImageController.java

@@ -2,17 +2,20 @@
 
 import ch.akop.homesystem.services.ImageCreatorService;
 import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
 import org.springframework.http.CacheControl;
 import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.CrossOrigin;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.servlet.mvc.method.annotation.StreamingResponseBody;
 
 import java.time.Duration;
 import java.time.temporal.ChronoUnit;
 
+@Slf4j
 @RestController
 @RequestMapping("/v1/images")
 @RequiredArgsConstructor
@@ -21,16 +24,20 @@ public class ImageController {
 
     private final ImageCreatorService imageCreatorService;
 
+    // @Cacheable("dailyImage")
     @GetMapping("daily.jpg")
-    public ResponseEntity<byte[]> getDailyImage() {
+    public ResponseEntity<StreamingResponseBody> getDailyImage() {
         var image = imageCreatorService.getLastImage();
+        imageCreatorService.increaseDownloadCounter();
+
         return ResponseEntity.ok()
                 .cacheControl(CacheControl.maxAge(Duration.of(12, ChronoUnit.HOURS)))
                 .eTag(image.getCreated().toString())
                 .contentType(MediaType.IMAGE_JPEG)
                 .headers(header -> header.add("prompt", image.getPrompt()))
-                .body(image.getImage());
+                .body(imageCreatorService::writeLastImageToStream);
 
     }
 
+
 }

src/main/java/ch/akop/homesystem/persistence/model/ImageOfOpenAI.java

@@ -5,6 +5,7 @@
 import lombok.Setter;
 
 import javax.persistence.*;
+import java.sql.Blob;
 import java.time.LocalDateTime;
 
 @Entity
@@ -24,6 +25,6 @@ public class ImageOfOpenAI {
     private String prompt;
 
     @Lob
-    private byte[] image;
+    private Blob image;
 
 }

src/main/java/ch/akop/homesystem/persistence/repository/OpenAIImageRepository.java

@@ -3,11 +3,14 @@
 import ch.akop.homesystem.persistence.model.ImageOfOpenAI;
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.stereotype.Repository;
+import org.springframework.transaction.annotation.Transactional;
 
 import java.time.LocalDateTime;
 import java.util.Optional;
 
 @Repository
 public interface OpenAIImageRepository extends JpaRepository<ImageOfOpenAI, LocalDateTime> {
+
+    @Transactional
     Optional<ImageOfOpenAI> findFirstByOrderByCreatedDesc();
 }

src/main/java/ch/akop/homesystem/services/ImageCreatorService.java

@@ -2,9 +2,15 @@
 
 import ch.akop.homesystem.persistence.model.ImageOfOpenAI;
 
+import java.io.OutputStream;
+
 public interface ImageCreatorService {
     void generateAndSendDailyImage();
 
     ImageOfOpenAI getLastImage();
 
+    void writeLastImageToStream(OutputStream outputStream);
+
+    void increaseDownloadCounter();
+
 }

src/main/java/ch/akop/homesystem/services/impl/ImageCreatorServiceImpl.java

@@ -8,16 +8,23 @@
 import ch.akop.homesystem.services.WeatherService;
 import ch.akop.weathercloud.Weather;
 import lombok.RequiredArgsConstructor;
+import lombok.SneakyThrows;
+import lombok.extern.slf4j.Slf4j;
+import org.hibernate.engine.jdbc.BlobProxy;
+import org.springframework.scheduling.annotation.Async;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
+import org.springframework.transaction.support.TransactionTemplate;
 
+import java.io.OutputStream;
 import java.util.List;
 import java.util.NoSuchElementException;
 
 import static ch.akop.homesystem.util.RandomUtil.pickRandomElement;
 import static ch.akop.weathercloud.rain.RainUnit.MILLIMETER_PER_HOUR;
 import static ch.akop.weathercloud.temperature.TemperatureUnit.DEGREE;
 
+@Slf4j
 @Service
 @RequiredArgsConstructor
 public class ImageCreatorServiceImpl implements ImageCreatorService {
@@ -26,6 +33,9 @@ public class ImageCreatorServiceImpl implements ImageCreatorService {
     private final OpenAIImageRepository imageRepository;
     private final MessageService messageService;
     private final WeatherService weatherService;
+    private final TransactionTemplate transactionTemplate;
+
+    byte[] lastImage;
 
 
     @Override
@@ -34,19 +44,46 @@ public void generateAndSendDailyImage() {
         imageService.requestImage(prompt)
                 .subscribe(image -> {
                     messageService.sendImageToMainChannel(image, prompt);
-                    imageRepository.save(new ImageOfOpenAI().setPrompt(prompt).setImage(image));
+                    imageRepository.save(new ImageOfOpenAI().setPrompt(prompt).setImage(BlobProxy.generateProxy(image)));
+                    lastImage = image;
                 });
     }
 
     @Override
-    @Transactional(readOnly = true)
+    @Transactional
     public ImageOfOpenAI getLastImage() {
-        var last = imageRepository.findFirstByOrderByCreatedDesc()
-                .orElseThrow(() -> new NoSuchElementException("There are no images right now."));
+        return getLastImageOrThrow();
+    }
+
+    @Override
+    @SneakyThrows
+    public void writeLastImageToStream(OutputStream outputStream) {
+        outputStream.write(getLastImageAsBytes());
+    }
 
-        last.setDownloaded(last.getDownloaded() + 1);
+    public synchronized byte[] getLastImageAsBytes() {
+        if (lastImage == null) {
+            lastImage = transactionTemplate.execute(status -> getLastImageAsBytesFromDatabase());
+        }
 
-        return last;
+        return lastImage;
+    }
+
+    @SneakyThrows
+    private byte[] getLastImageAsBytesFromDatabase() {
+        return getLastImageOrThrow().getImage().getBinaryStream().readAllBytes();
+    }
+
+    @Override
+    @Async
+    public void increaseDownloadCounter() {
+        imageRepository.findFirstByOrderByCreatedDesc()
+                .ifPresent(image -> image.setDownloaded(image.getDownloaded() + 1));
+    }
+
+    private ImageOfOpenAI getLastImageOrThrow() {
+        return imageRepository.findFirstByOrderByCreatedDesc()
+                .orElseThrow(() -> new NoSuchElementException("There are no images right now."));
     }
 
     private String generatePrompt() {