--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/net/httpclient/HttpInputStreamTest.java Fri Dec 09 11:35:02 2016 +0000
@@ -0,0 +1,333 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.Reader;
+import java.net.URI;
+import jdk.incubator.http.HttpClient;
+import jdk.incubator.http.HttpHeaders;
+import jdk.incubator.http.HttpRequest;
+import jdk.incubator.http.HttpResponse;
+import java.nio.ByteBuffer;
+import java.nio.charset.Charset;
+import java.util.Locale;
+import java.util.Optional;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionStage;
+import java.util.concurrent.Flow;
+import java.util.stream.Stream;
+
+/*
+ * @test
+ * @summary An example on how to read a response body with InputStream...
+ * @run main/othervm HttpInputStreamTest
+ * @author daniel fuchs
+ */
+public class HttpInputStreamTest {
+
+ public static boolean DEBUG = Boolean.getBoolean("test.debug");
+
+ /**
+ * A simple HttpResponse.BodyHandler that creates a live
+ * InputStream to read the response body from the underlying ByteBuffer
+ * Flow.
+ * The InputStream is made immediately available for consumption, before
+ * the response body is fully received.
+ */
+ public static class HttpInputStreamHandler
+ implements HttpResponse.BodyHandler<InputStream> {
+
+ public static final int MAX_BUFFERS_IN_QUEUE = 1;
+
+ private final int maxBuffers;
+
+ public HttpInputStreamHandler() {
+ this(MAX_BUFFERS_IN_QUEUE);
+ }
+
+ public HttpInputStreamHandler(int maxBuffers) {
+ this.maxBuffers = maxBuffers <= 0 ? MAX_BUFFERS_IN_QUEUE : maxBuffers;
+ }
+
+ @Override
+ public synchronized HttpResponse.BodyProcessor<InputStream>
+ apply(int i, HttpHeaders hh) {
+ return new HttpResponseInputStream(maxBuffers);
+ }
+
+ /**
+ * An InputStream built on top of the Flow API.
+ */
+ private static class HttpResponseInputStream extends InputStream
+ implements HttpResponse.BodyProcessor<InputStream> {
+
+ // An immutable ByteBuffer sentinel to mark that the last byte was received.
+ private static final ByteBuffer LAST = ByteBuffer.wrap(new byte[0]);
+
+ // A queue of yet unprocessed ByteBuffers received from the flow API.
+ private final BlockingQueue<ByteBuffer> buffers;
+ private volatile Flow.Subscription subscription;
+ private volatile boolean closed;
+ private volatile Throwable failed;
+ private volatile ByteBuffer current;
+
+ HttpResponseInputStream() {
+ this(MAX_BUFFERS_IN_QUEUE);
+ }
+
+ HttpResponseInputStream(int maxBuffers) {
+ int capacity = maxBuffers <= 0 ? MAX_BUFFERS_IN_QUEUE : maxBuffers;
+ this.buffers = new ArrayBlockingQueue<>(capacity);
+ }
+
+ @Override
+ public CompletionStage<InputStream> getBody() {
+ // Return the stream immediately, before the
+ // response body is received.
+ // This makes it possible for senAsync().get().body()
+ // to complete before the response body is received.
+ return CompletableFuture.completedStage(this);
+ }
+
+ // Returns the current byte buffer to read from.
+ // If the current buffer has no remaining data, will take the
+ // next buffer from the buffers queue, possibly blocking until
+ // a new buffer is made available through the Flow API, or the
+ // end of the flow is reached.
+ private ByteBuffer current() throws IOException {
+ while (current == null || !current.hasRemaining()) {
+ // Check whether the stream is claused or exhausted
+ if (closed || failed != null) {
+ throw new IOException("closed", failed);
+ }
+ if (current == LAST) break;
+
+ try {
+ // Take a new buffer from the queue, blocking
+ // if none is available yet...
+ if (DEBUG) System.err.println("Taking Buffer");
+ current = buffers.take();
+ if (DEBUG) System.err.println("Buffer Taken");
+
+ // Check whether some exception was encountered
+ // upstream
+ if (closed || failed != null) {
+ throw new IOException("closed", failed);
+ }
+
+ // Check whether we're done.
+ if (current == LAST) break;
+
+ // Inform the producer that it can start sending
+ // us a new buffer
+ Flow.Subscription s = subscription;
+ if (s != null) s.request(1);
+
+ } catch (InterruptedException ex) {
+ // continue
+ }
+ }
+ assert current == LAST || current.hasRemaining();
+ return current;
+ }
+
+ @Override
+ public int read(byte[] bytes, int off, int len) throws IOException {
+ // get the buffer to read from, possibly blocking if
+ // none is available
+ ByteBuffer buffer;
+ if ((buffer = current()) == LAST) return -1;
+
+ // don't attempt to read more than what is available
+ // in the current buffer.
+ int read = Math.min(buffer.remaining(), len);
+ assert read > 0 && read <= buffer.remaining();
+
+ // buffer.get() will do the boundary check for us.
+ buffer.get(bytes, off, read);
+ return read;
+ }
+
+ @Override
+ public int read() throws IOException {
+ ByteBuffer buffer;
+ if ((buffer = current()) == LAST) return -1;
+ return buffer.get() & 0xFF;
+ }
+
+ @Override
+ public void onSubscribe(Flow.Subscription s) {
+ this.subscription = s;
+ s.request(Math.max(2, buffers.remainingCapacity() + 1));
+ }
+
+ @Override
+ public synchronized void onNext(ByteBuffer t) {
+ try {
+ if (DEBUG) System.err.println("next buffer received");
+ buffers.put(t);
+ if (DEBUG) System.err.println("buffered offered");
+ } catch (Exception ex) {
+ failed = ex;
+ try {
+ close();
+ } catch (IOException ex1) {
+ // OK
+ }
+ }
+ }
+
+ @Override
+ public void onError(Throwable thrwbl) {
+ failed = thrwbl;
+ }
+
+ @Override
+ public synchronized void onComplete() {
+ subscription = null;
+ onNext(LAST);
+ }
+
+ @Override
+ public void close() throws IOException {
+ synchronized (this) {
+ closed = true;
+ Flow.Subscription s = subscription;
+ if (s != null) {
+ s.cancel();
+ }
+ subscription = null;
+ }
+ super.close();
+ }
+
+ }
+ }
+
+ /**
+ * Examine the response headers to figure out the charset used to
+ * encode the body content.
+ * If the content type is not textual, returns an empty Optional.
+ * Otherwise, returns the body content's charset, defaulting to
+ * ISO-8859-1 if none is explicitly specified.
+ * @param headers The response headers.
+ * @return The charset to use for decoding the response body, if
+ * the response body content is text/...
+ */
+ public static Optional<Charset> getCharset(HttpHeaders headers) {
+ Optional<String> contentType = headers.firstValue("Content-Type");
+ Optional<Charset> charset = Optional.empty();
+ if (contentType.isPresent()) {
+ final String[] values = contentType.get().split(";");
+ if (values[0].startsWith("text/")) {
+ charset = Optional.of(Stream.of(values)
+ .map(x -> x.toLowerCase(Locale.ROOT))
+ .map(String::trim)
+ .filter(x -> x.startsWith("charset="))
+ .map(x -> x.substring("charset=".length()))
+ .findFirst()
+ .orElse("ISO-8859-1"))
+ .map(Charset::forName);
+ }
+ }
+ return charset;
+ }
+
+ public static void main(String[] args) throws Exception {
+ HttpClient client = HttpClient.newHttpClient();
+ HttpRequest request = HttpRequest
+ .newBuilder(new URI("http://hg.openjdk.java.net/jdk9/sandbox/jdk/shortlog/http-client-branch/"))
+ .GET()
+ .build();
+
+ // This example shows how to return an InputStream that can be used to
+ // start reading the response body before the response is fully received.
+ // In comparison, the snipet below (which uses
+ // HttpResponse.BodyHandler.asString()) obviously will not return before the
+ // response body is fully read:
+ //
+ // System.out.println(
+ // client.sendAsync(request, HttpResponse.BodyHandler.asString()).get().body());
+
+ CompletableFuture<HttpResponse<InputStream>> handle =
+ client.sendAsync(request, new HttpInputStreamHandler());
+ if (DEBUG) System.err.println("Request sent");
+
+ HttpResponse<InputStream> pending = handle.get();
+
+ // At this point, the response headers have been received, but the
+ // response body may not have arrived yet. This comes from
+ // the implementation of HttpResponseInputStream::getBody above,
+ // which returns an already completed completion stage, without
+ // waiting for any data.
+ // We can therefore access the headers - and the body, which
+ // is our live InputStream, without waiting...
+ HttpHeaders responseHeaders = pending.headers();
+
+ // Get the charset declared in the response headers.
+ // The optional will be empty if the content type is not
+ // of type text/...
+ Optional<Charset> charset = getCharset(responseHeaders);
+
+ try (InputStream is = pending.body();
+ // We assume a textual content type. Construct an InputStream
+ // Reader with the appropriate Charset.
+ // charset.get() will throw NPE if the content is not textual.
+ Reader r = new InputStreamReader(is, charset.get())) {
+
+ char[] buff = new char[32];
+ int off=0, n=0;
+ if (DEBUG) System.err.println("Start receiving response body");
+ if (DEBUG) System.err.println("Charset: " + charset.get());
+
+ // Start consuming the InputStream as the data arrives.
+ // Will block until there is something to read...
+ while ((n = r.read(buff, off, buff.length - off)) > 0) {
+ assert (buff.length - off) > 0;
+ assert n <= (buff.length - off);
+ if (n == (buff.length - off)) {
+ System.out.print(buff);
+ off = 0;
+ } else {
+ off += n;
+ }
+ assert off < buff.length;
+ }
+
+ // last call to read may not have filled 'buff' completely.
+ // flush out the remaining characters.
+ assert off >= 0 && off < buff.length;
+ for (int i=0; i < off; i++) {
+ System.out.print(buff[i]);
+ }
+
+ // We're done!
+ System.out.println("Done!");
+ }
+ }
+
+}