tasks: 1 - 3

src/main/java/lab07/HttpHandler.java

 package lab07;
 
+import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.io.RandomAccessFile;
 import java.nio.ByteBuffer;
+import java.nio.channels.FileChannel;
 import java.nio.channels.SocketChannel;
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -25,7 +28,9 @@ class HttpHandler {
 		try {
 			request = getRequest(channel);
 			String resource = getResource(request);
-			
+			CompletableFuture<Void> future = transferFile(resource, channel);
+			//task: #3
+			future.handle((r,exc) -> { close(channel); return null;});
 		} catch (IOException e) {
 			writeStatus(Status.INTERNAL_SERVER_ERROR, channel);
 			writeString("", channel);
@@ -35,14 +40,31 @@ class HttpHandler {
 		}
 	}
 	
-	private CompletableFuture<Void> transferFile(String resource, SocketChannel channel) {
-		return null;
+	private void close(SocketChannel channel) {
+		try {
+			channel.close();
+		} catch (IOException e) {
+			log.warn("close", e);
+		}
 	}
 
+	private CompletableFuture<Void> transferFile(final String resource,final SocketChannel channel) {
+		//task: #2
+		return CompletableFuture.runAsync(() -> doTransferFile(resource, channel));
+	}
+
+	//task: #1
 	private void doTransferFile(final String resource, SocketChannel channel) {
-		@SuppressWarnings("unused")
 		Path filePath = getFilePath(resource);
-		//TODO implement data transfer from file to socket
+		try(RandomAccessFile raf = new RandomAccessFile(filePath.toFile(), "rw"); FileChannel fc = raf.getChannel()) {
+			writeStatus(Status.OK, channel);
+			fc.transferTo(0, raf.length(),channel);
+		} catch (FileNotFoundException e) {
+			writeStatus(Status.NOT_FOUND, channel);
+			writeString("'%s' not found".formatted(resource), channel);
+		} catch (IOException e) {
+			log.error("read file:", e);
+		}
 	}
 
 	private Path getFilePath(String resource) {