Content-length optimization

common/http/src/main/java/io/helidon/common/http/DataChunk.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2019 Oracle and/or its affiliates. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -66,7 +66,19 @@ static DataChunk create(byte[] bytes) {
      * @return a reusable data chunk with no release callback
      */
     static DataChunk create(boolean flush, ByteBuffer data) {
-        return create(flush, data, Utils.EMPTY_RUNNABLE);
+        return create(flush, data, Utils.EMPTY_RUNNABLE, false);
+    }
+
+    /**
+     * Creates a reusable data chunk.
+     *
+     * @param flush a signal that chunk should be written and flushed from any cache if possible
+     * @param data  a data chunk. Should not be reused until {@code releaseCallback} is used
+     * @param readOnly indicates underlying buffer is not reused
+     * @return a reusable data chunk with no release callback
+     */
+    static DataChunk create(boolean flush, ByteBuffer data, boolean readOnly) {
+        return create(flush, data, Utils.EMPTY_RUNNABLE, readOnly);
     }
 
     /**
@@ -78,6 +90,19 @@ static DataChunk create(boolean flush, ByteBuffer data) {
      * @return a reusable data chunk with a release callback
      */
     static DataChunk create(boolean flush, ByteBuffer data, Runnable releaseCallback) {
+        return create(flush, data, releaseCallback, false);
+    }
+
+    /**
+     * Creates a reusable data chunk.
+     *
+     * @param flush           a signal that chunk should be written and flushed from any cache if possible
+     * @param data            a data chunk. Should not be reused until {@code releaseCallback} is used
+     * @param releaseCallback a callback which is called when this chunk is completely processed and instance is free for reuse
+     * @param readOnly       indicates underlying buffer is not reused
+     * @return a reusable data chunk with a release callback
+     */
+    static DataChunk create(boolean flush, ByteBuffer data, Runnable releaseCallback, boolean readOnly) {
         return new DataChunk() {
             private boolean isReleased = false;
 
@@ -101,6 +126,11 @@ public void release() {
             public boolean isReleased() {
                 return isReleased;
             }
+
+            @Override
+            public boolean isReadOnly() {
+                return readOnly;
+            }
         };
     }
 
@@ -194,4 +224,29 @@ default void release() {
     default boolean flush() {
         return false;
     }
+
+    /**
+     * Makes a copy of this data chunk including its underlying {@link ByteBuffer}. This
+     * may be necessary for caching in case {@link ByteBuffer#rewind()} is called to
+     * reuse a byte buffer. Note that only the actual bytes used in the data chunk are
+     * copied, the resulting data chunk's capacity may be less than the original.
+     *
+     * @return A copy of this data chunk.
+     */
+    default DataChunk duplicate() {
+        byte[] bytes = new byte[data().limit()];
+        DataChunk dup = DataChunk.create(data().get(bytes));
+        dup.data().position(0);
+        return dup;
+    }
+
+    /**
+     * Returns {@code true} if the underlying byte buffer of this chunk is read
+     * only or {@code false} otherwise.
+     *
+     * @return Immutability outcome.
+     */
+    default boolean isReadOnly() {
+        return false;
+    }
 }

examples/webserver/streaming/src/main/java/io/helidon/webserver/examples/streaming/ServerFileReader.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2019 Oracle and/or its affiliates. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -64,11 +64,12 @@ public void request(long n) {
                             return;
                         }
                         if (bytes > 0) {
-                            buffer.rewind();
                             LOGGER.info(buffer.toString());
+                            buffer.flip();
                             s.onNext(DataChunk.create(buffer));
                             n--;
                         }
+                        buffer.rewind();
                     }
                 } catch (IOException e) {
                     s.onError(e);

examples/webserver/streaming/src/main/java/io/helidon/webserver/examples/streaming/StreamingService.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2019 Oracle and/or its affiliates. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -59,6 +59,8 @@ private void upload(ServerRequest request, ServerResponse response) {
 
     private void download(ServerRequest request, ServerResponse response) {
         LOGGER.info("Entering download ..." + Thread.currentThread());
+        long length = filePath.toFile().length();
+        response.headers().add("Content-Length", String.valueOf(length));
         response.send(new ServerFileReader(filePath));
         LOGGER.info("Exiting download ...");
     }

media/common/src/main/java/io/helidon/media/common/ContentWriters.java

@@ -158,7 +158,7 @@ public Flow.Publisher<DataChunk> apply(byte[] bytes) {
             } else {
                 bs = bytes;
             }
-            DataChunk chunk = DataChunk.create(false, ByteBuffer.wrap(bs));
+            DataChunk chunk = DataChunk.create(false, ByteBuffer.wrap(bs), true);
             return ReactiveStreamsAdapter.publisherToFlow(Mono.just(chunk));
         }
     }
@@ -195,7 +195,7 @@ public Flow.Publisher<DataChunk> apply(CharSequence s) {
             if (s == null || s.length() == 0) {
                 return ReactiveStreamsAdapter.publisherToFlow(Mono.empty());
             }
-            DataChunk chunk = DataChunk.create(false, charset.encode(s.toString()));
+            DataChunk chunk = DataChunk.create(false, charset.encode(s.toString()), true);
             return ReactiveStreamsAdapter.publisherToFlow(Mono.just(chunk));
         }
     }
@@ -220,7 +220,7 @@ public Flow.Publisher<DataChunk> apply(CharBuffer buffer) {
             if (buffer == null || buffer.size() == 0) {
                 return ReactiveStreamsAdapter.publisherToFlow(Mono.empty());
             }
-            final DataChunk chunk = DataChunk.create(false, buffer.encode(charset));
+            final DataChunk chunk = DataChunk.create(false, buffer.encode(charset), true);
             return ReactiveStreamsAdapter.publisherToFlow(Mono.just(chunk));
         }
     }

tests/apps/bookstore/bookstore-mp/src/test/java/io/helidon/tests/apps/bookstore/mp/BookResourceTest.java

@@ -33,6 +33,7 @@
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 
 class BookResourceTest {
 
@@ -53,27 +54,31 @@ void testBooks() {
                 .request()
                 .post(Entity.json(getBookAsJson()));
         assertEquals(Response.Status.OK.getStatusCode(), res.getStatus());
+        assertNotNull(res.getHeaderString("content-length"));
 
         assertBookStoreSize(1);
 
         res = client.target(getConnectionString("/books/123456"))
                 .request()
                 .get();
         assertEquals(Response.Status.OK.getStatusCode(), res.getStatus());
+        assertNotNull(res.getHeaderString("content-length"));
 
         assertBookStoreSize(1);
 
         res = client.target(getConnectionString("/books/123456"))
                 .request()
                 .put(Entity.json(getBookAsJson()));
         assertEquals(Response.Status.OK.getStatusCode(), res.getStatus());
+        assertNotNull(res.getHeaderString("content-length"));
 
         assertBookStoreSize(1);
 
         res = client.target(getConnectionString("/books/123456"))
                 .request()
                 .delete();
         assertEquals(Response.Status.OK.getStatusCode(), res.getStatus());
+        assertNotNull(res.getHeaderString("content-length"));
 
         assertBookStoreSize(0);
     }

tests/apps/bookstore/bookstore-se/src/test/java/io/helidon/tests/apps/bookstore/se/MainTest.java

@@ -35,6 +35,8 @@
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
 public class MainTest {
 
     private static WebServer webServer;
@@ -70,6 +72,7 @@ public void testHelloWorld() throws Exception {
 
         conn = getURLConnection("GET","/books");
         Assertions.assertEquals(200, conn.getResponseCode(), "HTTP response1");
+        Assertions.assertNotNull(conn.getHeaderField("content-length"));
 
         conn = getURLConnection("POST","/books");
         writeJsonContent(conn, json);
@@ -81,16 +84,17 @@ public void testHelloWorld() throws Exception {
         JsonObject jsonObject = jsonReader.readObject();
         Assertions.assertEquals("123456", jsonObject.getString("isbn"),
                 "Checking if correct ISBN");
+        Assertions.assertNotNull(conn.getHeaderField("content-length"));
 
         conn = getURLConnection("GET","/books/0000");
         Assertions.assertEquals(404, conn.getResponseCode(), "HTTP response GET bad ISBN");
 
         conn = getURLConnection("GET","/books");
         Assertions.assertEquals(200, conn.getResponseCode(), "HTTP response list books");
+        Assertions.assertNotNull(conn.getHeaderField("content-length"));
 
         conn = getURLConnection("DELETE","/books/123456");
         Assertions.assertEquals(200, conn.getResponseCode(), "HTTP response delete book");
-
     }
 
     private HttpURLConnection getURLConnection(String method, String path) throws Exception {

tests/apps/bookstore/common/src/main/java/io/helidon/tests/apps/bookstore/mp/BookStore.java

@@ -56,3 +56,4 @@ public void remove(String isbn) {
     public boolean contains(String isbn) { return store.containsKey(isbn); }
 
 }
+

tests/functional/bookstore/src/test/java/io/helidon/tests/apps/bookstore/se/MainTest.java

@@ -106,7 +106,6 @@ void basicTestJsonMP() throws Exception {
         runJsonFunctionalTest("mp", "");
     }
 
-
     @Test
     void basicTestMetricsHealthSE() throws Exception {
         runMetricsAndHealthTest("se", "jsonp");

webserver/jersey/src/main/java/io/helidon/webserver/jersey/ResponseWriter.java

@@ -127,8 +127,6 @@ public void write(int b) throws IOException {
 
         if (contentLength >= 0) {
             res.headers().put(Http.Header.CONTENT_LENGTH, String.valueOf(contentLength));
-        } else {
-            res.headers().put(Http.Header.TRANSFER_ENCODING, "chunked");
         }
 
         for (Map.Entry<String, List<String>> entry : context.getStringHeaders().entrySet()) {

webserver/webserver/src/main/java/io/helidon/webserver/BareResponseImpl.java

@@ -75,6 +75,9 @@ class BareResponseImpl implements BareResponse {
     private final GenericFutureListener<? extends Future<? super Void>> channelClosedListener;
 
     private volatile Flow.Subscription subscription;
+    private volatile DataChunk firstChunk;
+    private volatile DefaultHttpResponse response;
+    private volatile boolean lengthOptimization;
 
     /**
      * @param ctx the channel handler context
@@ -130,7 +133,7 @@ public void writeStatusAndHeaders(Http.ResponseStatus status, Map<String, List<S
             throw new IllegalStateException("Status and headers were already sent");
         }
 
-        DefaultHttpResponse response = new DefaultHttpResponse(HTTP_1_1, valueOf(status.code()));
+        response = new DefaultHttpResponse(HTTP_1_1, valueOf(status.code()));
         for (Map.Entry<String, List<String>> headerEntry : headers.entrySet()) {
             response.headers().add(headerEntry.getKey(), headerEntry.getValue());
         }
@@ -140,24 +143,25 @@ public void writeStatusAndHeaders(Http.ResponseStatus status, Map<String, List<S
                 .filter(header -> header.startsWith(HTTP_2_HEADER_PREFIX))
                 .forEach(header -> response.headers().add(header, requestHeaders.get(header)));
 
+        // Set chunked if length not set, may switch to length later
+        boolean lengthSet = HttpUtil.isContentLengthSet(response);
+        if (!lengthSet) {
+            lengthOptimization = status.code() == Http.Status.OK_200.code()
+                    && !HttpUtil.isTransferEncodingChunked(response);
+            HttpUtil.setTransferEncodingChunked(response, true);
+        }
+
+        // Add keep alive header as per:
+        // http://www.w3.org/Protocols/HTTP/1.1/draft-ietf-http-v11-spec-01.html#Connection
         if (keepAlive) {
-            if (status.code() != Http.Status.NO_CONTENT_204.code()) {
-                HttpUtil.setTransferEncodingChunked(response, true);
-            }
-            // Add keep alive header as per:
-            // - http://www.w3.org/Protocols/HTTP/1.1/draft-ietf-http-v11-spec-01.html#Connection
             response.headers().set(HttpHeaderNames.CONNECTION, HttpHeaderValues.KEEP_ALIVE);
         }
 
-        LOGGER.finest(() -> log("Writing headers: " + status));
-        ctx.writeAndFlush(response)
-                .addListener(future -> {
-                    if (future.isSuccess()) {
-                        headersFuture.complete(this);
-                    }
-                })
-                .addListener(completeOnFailureListener("An exception occurred when writing headers."))
-                .addListener(ChannelFutureListener.CLOSE_ON_FAILURE);
+        // Content length optimization attempt
+        if (!lengthOptimization) {
+            LOGGER.finest(() -> log("Writing headers: " + status));
+            initWriteResponse();
+        }
     }
 
     /**
@@ -209,7 +213,21 @@ private void completeInternal(Throwable throwable) {
         }
     }
 
+    /**
+     * Write last HTTP content. If length optimization is active and a first chunk is cached,
+     * switch content encoding and write response.
+     *
+     * @param throwable A throwable.
+     * @param closeAction Close action listener.
+     */
     private void writeLastContent(final Throwable throwable, final ChannelFutureListener closeAction) {
+        if (lengthOptimization) {
+            if (firstChunk != null) {
+                HttpUtil.setTransferEncodingChunked(response, false);
+                HttpUtil.setContentLength(response, firstChunk.data().limit());
+            }
+            initWriteResponse();
+        }
         ctx.writeAndFlush(LAST_HTTP_CONTENT)
                 .addListener(completeOnFailureListener("An exception occurred when writing last http content."))
                 .addListener(completeOnSuccessListener(throwable))
@@ -245,7 +263,42 @@ public void onNext(DataChunk data) {
             throw new IllegalStateException("Response is already closed!");
         }
         if (data != null) {
+            if (lengthOptimization) {
+                if (firstChunk == null) {
+                    firstChunk = data.isReadOnly() ? data : data.duplicate();      // cache first chunk
+                    return;
+                }
+                initWriteResponse();
+            }
+            sendData(data);
+        }
+    }
 
+    /**
+     * Initiates write of response and sends first chunk if available.
+     *
+     * @return Future of response or first chunk.
+     */
+    private ChannelFuture initWriteResponse() {
+        ChannelFuture cf = ctx.write(response)
+                .addListener(future -> {
+                    if (future.isSuccess()) {
+                        headersFuture.complete(this);
+                    }
+                })
+                .addListener(completeOnFailureListener("An exception occurred when writing headers."))
+                .addListener(ChannelFutureListener.CLOSE_ON_FAILURE);
+        response = null;
+        if (firstChunk != null) {
+            cf = sendData(firstChunk);
+            firstChunk.release();
+            firstChunk = null;
+        }
+        lengthOptimization = false;
+        return cf;
+    }
+
+    private ChannelFuture sendData(DataChunk data) {
             LOGGER.finest(() -> log("Sending data chunk"));
 
             DefaultHttpContent httpContent = new DefaultHttpContent(Unpooled.wrappedBuffer(data.data()));
@@ -259,15 +312,13 @@ public void onNext(DataChunk data) {
                 channelFuture = ctx.write(httpContent);
             }
 
-            channelFuture
+            return channelFuture
                     .addListener(future -> {
                         data.release();
                         LOGGER.finest(() -> log("Data chunk sent with result: " + future.isSuccess()));
                     })
                     .addListener(completeOnFailureListener("Failure when sending a content!"))
                     .addListener(ChannelFutureListener.CLOSE_ON_FAILURE);
-
-        }
     }
 
     private String log(String s) {