BE add file IO service, config, exception

SpringDataPlatform/backend/DataPlatform/FlinkRestService/src/main/java/com/yen/FlinkRestService/Config/StorageProperties.java

@@ -0,0 +1,23 @@
+package com.yen.FlinkRestService.Config;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+//@ConfigurationProperties("storage")
+public class StorageProperties {
+
+    /**
+     * Folder location for storing files
+     */
+    private String location = "upload-dir";
+
+    public String getLocation() {
+        return location;
+    }
+
+    public void setLocation(String location) {
+        this.location = location;
+    }
+
+}

SpringDataPlatform/backend/DataPlatform/FlinkRestService/src/main/java/com/yen/FlinkRestService/Service/FileSystemStorageService.java

@@ -0,0 +1,126 @@
+package com.yen.FlinkRestService.Service;
+
+/**
+ *  Service for file IO
+ *
+ *  https://spring.io/guides/gs/uploading-files/
+ */
+
+import com.yen.FlinkRestService.Config.StorageProperties;
+import com.yen.FlinkRestService.exception.StorageException;
+import com.yen.FlinkRestService.exception.StorageFileNotFoundException;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.UrlResource;
+import org.springframework.stereotype.Service;
+import org.springframework.util.FileSystemUtils;
+import org.springframework.util.StringUtils;
+import org.springframework.web.multipart.MultipartFile;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.MalformedURLException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
+import java.util.stream.Stream;
+
+@Service
+public class FileSystemStorageService implements StorageService {
+
+    private final Path rootLocation;
+
+    @Autowired
+    public FileSystemStorageService(StorageProperties properties) {
+
+        if(properties.getLocation().trim().length() == 0){
+            throw new StorageException("File upload location can not be Empty.");
+        }
+
+        this.rootLocation = Paths.get(properties.getLocation());
+    }
+
+    @Override
+    public void store(MultipartFile file) {
+
+        try {
+            if (file.isEmpty()) {
+                throw new StorageException("Failed to store empty file.");
+            }
+            Path destinationFile = this.rootLocation.resolve(
+                            Paths.get(file.getOriginalFilename()))
+                    .normalize().toAbsolutePath();
+            if (!destinationFile.getParent().equals(this.rootLocation.toAbsolutePath())) {
+                // This is a security check
+                throw new StorageException(
+                        "Cannot store file outside current directory.");
+            }
+            try (InputStream inputStream = file.getInputStream()) {
+                Files.copy(inputStream, destinationFile,
+                        StandardCopyOption.REPLACE_EXISTING);
+            }
+        }
+        catch (IOException e) {
+            throw new StorageException("Failed to store file.", e);
+        }
+    }
+
+    @Override
+    public Stream<Path> loadAll() {
+
+        try {
+            return Files.walk(this.rootLocation, 1)
+                    .filter(path -> !path.equals(this.rootLocation))
+                    .map(this.rootLocation::relativize);
+        }
+        catch (IOException e) {
+            throw new StorageException("Failed to read stored files", e);
+        }
+
+    }
+
+    @Override
+    public Path load(String filename) {
+
+        return rootLocation.resolve(filename);
+    }
+
+    @Override
+    public Resource loadAsResource(String filename) {
+
+        try {
+            Path file = load(filename);
+            Resource resource = new UrlResource(file.toUri());
+            if (resource.exists() || resource.isReadable()) {
+                return resource;
+            }
+            else {
+                throw new StorageFileNotFoundException(
+                        "Could not read file: " + filename);
+
+            }
+        }
+        catch (MalformedURLException e) {
+            throw new StorageFileNotFoundException("Could not read file: " + filename, e);
+        }
+    }
+
+    @Override
+    public void deleteAll() {
+
+        FileSystemUtils.deleteRecursively(rootLocation.toFile());
+    }
+
+    @Override
+    public void init() {
+
+        try {
+            Files.createDirectories(rootLocation);
+        }
+        catch (IOException e) {
+            throw new StorageException("Could not initialize storage", e);
+        }
+    }
+
+}

SpringDataPlatform/backend/DataPlatform/FlinkRestService/src/main/java/com/yen/FlinkRestService/Service/StorageService.java

@@ -0,0 +1,25 @@
+package com.yen.FlinkRestService.Service;
+
+/** https://spring.io/guides/gs/uploading-files/ */
+
+import org.springframework.core.io.Resource;
+import org.springframework.web.multipart.MultipartFile;
+
+import java.nio.file.Path;
+import java.util.stream.Stream;
+
+public interface StorageService {
+
+    void init();
+
+    void store(MultipartFile file);
+
+    Stream<Path> loadAll();
+
+    Path load(String filename);
+
+    Resource loadAsResource(String filename);
+
+    void deleteAll();
+
+}

SpringDataPlatform/backend/DataPlatform/FlinkRestService/src/main/java/com/yen/FlinkRestService/exception/StorageException.java

@@ -0,0 +1,12 @@
+package com.yen.FlinkRestService.exception;
+
+public class StorageException extends RuntimeException {
+
+    public StorageException(String message) {
+        super(message);
+    }
+
+    public StorageException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}

SpringDataPlatform/backend/DataPlatform/FlinkRestService/src/main/java/com/yen/FlinkRestService/exception/StorageFileNotFoundException.java

@@ -0,0 +1,12 @@
+package com.yen.FlinkRestService.exception;
+
+public class StorageFileNotFoundException extends StorageException {
+
+    public StorageFileNotFoundException(String message) {
+        super(message);
+    }
+
+    public StorageFileNotFoundException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}