test/jdk/java/net/httpclient/BodyProcessorInputStreamTest.java
branchhttp-client-branch
changeset 55763 634d8e14c172
child 49765 ee6f7a61f3a5
child 56089 42208b2f224e
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/net/httpclient/BodyProcessorInputStreamTest.java	Sun Nov 05 17:32:13 2017 +0000
@@ -0,0 +1,161 @@
+/*
+ * Copyright (c) 2017, 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.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+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;
+import static java.lang.System.err;
+
+/*
+ * @test
+ * @bug 8187503
+ * @summary An example on how to read a response body with InputStream...
+ * @run main/othervm -Dtest.debug=true BodyProcessorInputStreamTest
+ * @author daniel fuchs
+ */
+public class BodyProcessorInputStreamTest {
+
+    public static boolean DEBUG = Boolean.getBoolean("test.debug");
+
+    /**
+     * 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, HttpResponse.BodyHandler.asInputStream());
+        if (DEBUG) 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) err.println("Start receiving response body");
+            if (DEBUG) 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!");
+        }
+    }
+
+}