jdk/src/java.httpclient/share/classes/java/net/http/HttpRequest.java
changeset 36131 379db4b2f95d
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/java.httpclient/share/classes/java/net/http/HttpRequest.java	Thu Feb 25 23:14:22 2016 +0000
@@ -0,0 +1,871 @@
+/*
+ * Copyright (c) 2015, 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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.
+ */
+
+package java.net.http;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.UncheckedIOException;
+import java.net.URI;
+import java.net.ProxySelector;
+import java.nio.ByteBuffer;
+import java.nio.channels.FileChannel;
+import java.nio.charset.*;
+import java.nio.file.Path;
+import java.util.Iterator;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.TimeUnit;
+import java.util.function.LongConsumer;
+
+/**
+ * Represents one HTTP request which can be sent to a server. {@code
+ * HttpRequest}s are built from {@code HttpRequest} {@link HttpRequest.Builder
+ * builder}s. {@code HttpRequest} builders are obtained from a {@link HttpClient}
+ * by calling {@link HttpClient#request(java.net.URI) HttpClient.request}, or
+ * by calling {@link #create(java.net.URI) HttpRequest.create} which returns a
+ * builder on the <a href="HttpClient.html#defaultclient">default</a> client.
+ * A request's {@link java.net.URI}, headers and body can be set. Request bodies
+ * are provided through a {@link BodyProcessor} object. Once all required
+ * parameters have been set in the builder, one of the builder methods should be
+ * called, which sets the request method and returns a {@code HttpRequest}.
+ * These methods are {@link Builder#GET() GET}, {@link HttpRequest.Builder#POST()
+ * POST} and {@link HttpRequest.Builder#PUT() PUT} which return a GET, POST or
+ * PUT request respectively. Alternatively, {@link
+ * HttpRequest.Builder#method(String) method} can be called to set an arbitrary
+ * method type (and return a {@code HttpRequest}). Builders can also be copied
+ * and modified multiple times in order to build multiple related requests that
+ * differ in some parameters.
+ *
+ * <p> Two simple, example HTTP interactions are shown below:
+ * <pre>
+ * {@code
+ *      // GET
+ *      HttpResponse response = HttpRequest
+ *          .create(new URI("http://www.foo.com"))
+ *          .headers("Foo", "foovalue", "Bar", "barvalue")
+ *          .GET()
+ *          .response();
+ *
+ *      int statusCode = response.statusCode();
+ *      String responseBody = response.body(asString());
+ *
+ *      // POST
+ *      response = HttpRequest
+ *          .create(new URI("http://www.foo.com"))
+ *          .body(fromString("param1=foo,param2=bar"))
+ *          .POST()
+ *          .response();}
+ * </pre>
+ *
+ * <p> The request is sent and the response obtained by calling one of the
+ * following methods.
+ * <ul><li>{@link #response() response} blocks until the entire request has been
+ * sent and the response status code and headers have been received.</li>
+ * <li>{@link #responseAsync() responseAsync} sends the request and receives the
+ * response asynchronously. Returns immediately with a
+ * {@link java.util.concurrent.CompletableFuture CompletableFuture}&lt;{@link
+ * HttpResponse}&gt;.</li>
+ * <li>{@link #multiResponseAsync(HttpResponse.MultiProcessor) multiResponseAsync}
+ * sends the request asynchronously, expecting multiple responses. This
+ * capability is of most relevance to HTTP/2 server push, but can be used for
+ * single responses (HTTP/1.1 or HTTP/2) also.</li>
+ * </ul>
+ *
+ * <p> Once a request has been sent, it is an error to try and send it again.
+ *
+ * <p> Once a {@code HttpResponse} is received, the headers and response code are
+ * available. The body can then be received by calling one of the body methods
+ * on {@code HttpResponse}.
+ *
+ * <p> See below for discussion of synchronous versus asynchronous usage.
+ *
+ * <p> <b>Request bodies</b>
+ *
+ * <p> Request bodies are sent using one of the request processor implementations
+ * below provided in {@code HttpRequest}, or else a custom implementation can be
+ * used.
+ * <ul>
+ * <li>{@link #fromByteArray(byte[]) } from byte array</li>
+ * <li>{@link #fromByteArrays(java.util.Iterator) fromByteArrays(Iterator)}
+ *      from an iterator of byte arrays</li>
+ * <li>{@link #fromFile(java.nio.file.Path) fromFile(Path)} from the file located
+ *     at the given Path</li>
+ * <li>{@link #fromString(java.lang.String) fromString(String)} from a String </li>
+ * <li>{@link #fromInputStream(java.io.InputStream) fromInputStream(InputStream)}
+ *      request body from InputStream</li>
+ * <li>{@link #noBody() } no request body is sent</li>
+ * </ul>
+ *
+ * <p> <b>Response bodies</b>
+ *
+ * <p> Responses bodies are handled by the {@link HttpResponse.BodyProcessor}
+ * {@code <T>} supplied to the {@link HttpResponse#body(HttpResponse.BodyProcessor)
+ * HttpResponse.body} and {@link HttpResponse#bodyAsync(HttpResponse.BodyProcessor)
+ * HttpResponse.bodyAsync} methods. Some implementations of {@code
+ * HttpResponse.BodyProcessor} are provided in {@link HttpResponse}:
+ * <ul>
+ * <li>{@link HttpResponse#asByteArray() } stores the body in a byte array</li>
+ * <li>{@link HttpResponse#asString()} stores the body as a String </li>
+ * <li>{@link HttpResponse#asFile(java.nio.file.Path) } stores the body in a
+ * named file</li>
+ * <li>{@link HttpResponse#ignoreBody() } ignores any received response body</li>
+ * </ul>
+ *
+ * <p> The output of a response processor is the response body, and its
+ * parameterized type {@code T} determines the type of the body object returned
+ * from {@code HttpResponse.body} and {@code HttpResponse.bodyAsync}. Therefore,
+ * as an example, the second response processor in the list above has the type
+ * {@code HttpResponse.BodyProcessor<String>} which means the type returned by
+ * {@code HttpResponse.body()} is a String. Response processors can be defined
+ * to return potentially any type as body.
+ *
+ * <p> <b>Multi responses</b>
+ *
+ * <p> With HTTP/2 it is possible for a server to return a main response and zero
+ * or more additional responses (known as server pushes) to a client-initiated
+ * request. These are handled using a special response processor called {@link
+ * HttpResponse.MultiProcessor}.
+ *
+ * <p> <b>Blocking/asynchronous behavior and thread usage</b>
+ *
+ * <p> There are two styles of request sending: <i>synchronous</i> and
+ * <i>asynchronous</i>. {@link #response() response} blocks the calling thread
+ * until the request has been sent and the response received.
+ *
+ * <p> {@link #responseAsync() responseAsync} is asynchronous and returns
+ * immediately with a {@link java.util.concurrent.CompletableFuture}&lt;{@link
+ * HttpResponse}&gt; and when this object completes (in a background thread) the
+ * response has been received.
+ *
+ * <p> {@link #multiResponseAsync(HttpResponse.MultiProcessor) multiResponseAsync}
+ * is the variant for multi responses and is also asynchronous.
+ *
+ * <p> CompletableFutures can be combined in different ways to declare the
+ * dependencies among several asynchronous tasks, while allowing for the maximum
+ * level of parallelism to be utilized.
+ *
+ * <p> <b>Security checks</b>
+ *
+ * <p> If a security manager is present then security checks are performed by
+ * the {@link #response() } and {@link #responseAsync() } methods. A {@link
+ * java.net.URLPermission} or {@link java.net.SocketPermission} is required to
+ * access any destination origin server and proxy server utilised. URLPermissions
+ * should be preferred in policy files over SocketPermissions given the more
+ * limited scope of URLPermission. Permission is always implicitly granted to a
+ * system's default proxies. The URLPermission form used to access proxies uses
+ * a method parameter of "CONNECT" (for all kinds of proxying) and a url string
+ * of the form "socket://host:port" where host and port specify the proxy's
+ * address.
+ *
+ * <p> <b>Examples</b>
+ * <pre>
+ *     import static java.net.http.HttpRequest.*;
+ *     import static java.net.http.HttpResponse.*;
+ *
+ *     //Simple blocking
+ *
+ *     HttpResponse r1 = HttpRequest.create(new URI("http://www.foo.com/"))
+ *                                  .GET()
+ *                                 .response();
+ *     int responseCode = r1.statusCode());
+ *     String body = r1.body(asString());
+ *
+ *     HttpResponse r2 = HttpRequest.create(new URI("http://www.foo.com/"))
+ *                                  .GET()
+ *                                  .response();
+ *
+ *     System.out.println("Response was " + r1.statusCode());
+ *     Path body1 = r2.body(asFile(Paths.get("/tmp/response.txt")));
+ *     // Content stored in /tmp/response.txt
+ *
+ *     HttpResponse r3 = HttpRequest.create(new URI("http://www.foo.com/"))
+ *                                  .body(fromString("param1=1, param2=2"))
+ *                                  .POST()
+ *                                  .response();
+ *
+ *     Void body2 = r3.body(ignoreBody()); // body is Void in this case
+ * </pre>
+ *
+ * <p><b>Asynchronous Example</b>
+ *
+ * <p> All of the above examples will work asynchronously, if {@link
+ * #responseAsync()} is used instead of {@link #response()} in which case the
+ * returned object is a {@code CompletableFuture<HttpResponse>} instead of
+ * {@code HttpResponse}. The following example shows how multiple requests can
+ * be sent asynchronously. It also shows how dependent asynchronous operations
+ * (receiving response, and receiving response body) can be chained easily using
+ * one of the many methods in {@code CompletableFuture}.
+ * <pre>
+ * {@code
+ *      // fetch a list of target URIs asynchronously and store them in Files.
+ *
+ *      List<URI> targets = ...
+ *
+ *      List<CompletableFuture<File>> futures = targets
+ *          .stream()
+ *          .map(target -> {
+ *              return HttpRequest
+ *                  .create(target)
+ *                  .GET()
+ *                  .responseAsync()
+ *                  .thenCompose(response -> {
+ *                      Path dest = Paths.get("base", target.getPath());
+ *                      if (response.statusCode() == 200) {
+ *                          return response.bodyAsync(asFile(dest));
+ *                      } else {
+ *                          return CompletableFuture.completedFuture(dest);
+ *                      }
+ *                  })
+ *                  // convert Path -> File
+ *                  .thenApply((Path dest) -> {
+ *                      return dest.toFile();
+ *                  });
+ *              })
+ *          .collect(Collectors.toList());
+ *
+ *      // all async operations waited for here
+ *
+ *      CompletableFuture.allOf(futures.toArray(new CompletableFuture<?>[0]))
+ *          .join();
+ *
+ *      // all elements of futures have completed and can be examined.
+ *      // Use File.exists() to check whether file was successfully downloaded
+ * }
+ * </pre>
+ *
+ * @since 9
+ */
+public abstract class HttpRequest {
+
+    HttpRequest() {}
+
+    /**
+     * A builder of {@link HttpRequest}s. {@code HttpRequest.Builder}s are
+     * created by calling {@link HttpRequest#create(URI)} or {@link
+     * HttpClient#request(URI)}.
+     *
+     * <p> Each of the setter methods in this class modifies the state of the
+     * builder and returns <i>this</i> (ie. the same instance). The methods are
+     * not synchronized and should not be called from multiple threads without
+     * external synchronization.
+     *
+     * <p> The build methods return a new {@code HttpRequest} each time they are
+     * called.
+     *
+     * @since 9
+     */
+    public abstract static class Builder {
+
+        Builder() {}
+
+        /**
+         * Sets this HttpRequest's request URI.
+         *
+         * @param uri the request URI
+         * @return this request builder
+         */
+        public abstract Builder uri(URI uri);
+
+        /**
+         * Specifies whether this request will automatically follow redirects
+         * issued by the server. The default value for this setting is the value
+         * of {@link HttpClient#followRedirects() }
+         *
+         * @param policy the redirection policy
+         * @return this request builder
+         */
+        public abstract Builder followRedirects(HttpClient.Redirect policy);
+
+        /**
+         * Request server to acknowledge request before sending request
+         * body. This is disabled by default. If enabled, the server is requested
+         * to send an error response or a 100-Continue response before the client
+         * sends the request body. This means the request processor for the
+         * request will not be invoked until this interim response is received.
+         *
+         * @param enable {@code true} if Expect continue to be sent
+         * @return this request builder
+         */
+        public abstract Builder expectContinue(boolean enable);
+
+        /**
+         * Overrides the {@link HttpClient#version()  } setting for this
+         * request.
+         *
+         * @param version the HTTP protocol version requested
+         * @return this request builder
+         */
+        public abstract Builder version(HttpClient.Version version);
+
+        /**
+         * Adds the given name value pair to the set of headers for this request.
+         *
+         * @param name the header name
+         * @param value the header value
+         * @return this request builder
+         */
+        public abstract Builder header(String name, String value);
+
+        /**
+         * Overrides the ProxySelector set on the request's client for this
+         * request.
+         *
+         * @param proxy the ProxySelector to use
+         * @return this request builder
+         */
+        public abstract Builder proxy(ProxySelector proxy);
+
+        /**
+         * Adds the given name value pairs to the set of headers for this
+         * request. The supplied Strings must alternate as names and values.
+         *
+         * @param headers the list of String name value pairs
+         * @return this request builder
+         * @throws IllegalArgumentException if there is an odd number of
+         *                                  parameters
+         */
+        public abstract Builder headers(String... headers);
+
+        /**
+         * Sets a timeout for this request. If the response is not received
+         * within the specified timeout then a {@link HttpTimeoutException} is
+         * thrown from {@link #response() } or {@link #responseAsync() }
+         * completes exceptionally with a {@code HttpTimeoutException}.
+         *
+         * @param unit the timeout units
+         * @param timeval the number of units to wait for
+         * @return this request builder
+         */
+        public abstract Builder timeout(TimeUnit unit, long timeval);
+
+        /**
+         * Sets the given name value pair to the set of headers for this
+         * request. This overwrites any previously set values for name.
+         *
+         * @param name the header name
+         * @param value the header value
+         * @return this request builder
+         */
+        public abstract Builder setHeader(String name, String value);
+
+        /**
+         * Sets a request body for this builder. See {@link HttpRequest}
+         * for example {@code BodyProcessor} implementations.
+         * If no body is specified, then no body is sent with the request.
+         *
+         * @param reqproc the request body processor
+         * @return this request builder
+         */
+        public abstract Builder body(BodyProcessor reqproc);
+
+        /**
+         * Builds and returns a GET {@link HttpRequest} from this builder.
+         *
+         * @return a {@code HttpRequest}
+         */
+        public abstract HttpRequest GET();
+
+        /**
+         * Builds and returns a POST {@link HttpRequest} from this builder.
+         *
+         * @return a {@code HttpRequest}
+         */
+        public abstract HttpRequest POST();
+
+        /**
+         * Builds and returns a PUT {@link HttpRequest} from this builder.
+         *
+         * @return a {@code HttpRequest}
+         */
+        public abstract HttpRequest PUT();
+
+        /**
+         * Builds and returns a {@link HttpRequest} from this builder using
+         * the given method String. The method string is case-sensitive, and
+         * may be rejected if an upper-case string is not used.
+         *
+         * @param method the method to use
+         * @return a {@code HttpRequest}
+         * @throws IllegalArgumentException if an unrecognised method is used
+         */
+        public abstract HttpRequest method(String method);
+
+        /**
+         * Returns an exact duplicate copy of this Builder based on current
+         * state. The new builder can then be modified independently of this
+         * builder.
+         *
+         * @return an exact copy of this Builder
+         */
+        public abstract Builder copy();
+    }
+
+    /**
+     * Creates a HttpRequest builder from the <i>default</i> HttpClient.
+     *
+     * @param uri the request URI
+     * @return a new request builder
+     */
+    public static HttpRequest.Builder create(URI uri) {
+        return HttpClient.getDefault().request(uri);
+    }
+
+    /**
+     * Returns the follow-redirects setting for this request.
+     *
+     * @return follow redirects setting
+     */
+    public abstract HttpClient.Redirect followRedirects();
+
+    /**
+     * Returns the response to this request, by sending it and blocking if
+     * necessary to get the response. The {@link HttpResponse} contains the
+     * response status and headers.
+     *
+     * @return a HttpResponse for this request
+     * @throws IOException if an I/O error occurs
+     * @throws InterruptedException if the operation was interrupted
+     * @throws SecurityException if the caller does not have the required
+     *                           permission
+     * @throws IllegalStateException if called more than once or if
+     *                               responseAsync() called previously
+     */
+    public abstract HttpResponse response()
+        throws IOException, InterruptedException;
+
+    /**
+     * Sends the request and returns the response asynchronously. This method
+     * returns immediately with a {@link CompletableFuture}&lt;{@link
+     * HttpResponse}&gt;
+     *
+     * @return a {@code CompletableFuture<HttpResponse>}
+     * @throws IllegalStateException if called more than once or if response()
+     *                               called previously.
+     */
+    public abstract CompletableFuture<HttpResponse> responseAsync();
+
+    /**
+     * Sends the request asynchronously expecting multiple responses.
+     *
+     * <p> This method must be given a {@link HttpResponse.MultiProcessor} to
+     * handle the multiple responses.
+     *
+     * <p> If a security manager is set, the caller must possess a {@link
+     * java.net.URLPermission} for the request's URI, method and any user set
+     * headers. The security manager is also checked for each incoming
+     * additional server generated request/response. Any request that fails the
+     * security check, is canceled and ignored.
+     *
+     * <p> This method can be used for both HTTP/1.1 and HTTP/2, but in cases
+     * where multiple responses are not supported, the MultiProcessor
+     * only receives the main response.
+     *
+     * <p> The aggregate {@code CompletableFuture} returned from this method
+     * returns a {@code <U>} defined by the {@link HttpResponse.MultiProcessor}
+     * implementation supplied. This will typically be a Collection of
+     * HttpResponses or of some response body type.
+     *
+     * @param <U> the aggregate response type
+     * @param rspproc the MultiProcessor for the request
+     * @return a {@code CompletableFuture<U>}
+     * @throws IllegalStateException if the request has already been sent.
+     */
+    public abstract <U> CompletableFuture<U>
+    multiResponseAsync(HttpResponse.MultiProcessor<U> rspproc);
+
+    /**
+     * Returns the request method for this request. If not set explicitly,
+     * the default method for any request is "GET".
+     *
+     * @return this request's method
+     */
+    public abstract String method();
+
+    /**
+     * Returns this request's {@link HttpRequest.Builder#expectContinue(boolean)
+     * expect continue } setting.
+     *
+     * @return this request's expect continue setting
+     */
+    public abstract boolean expectContinue();
+
+    /**
+     * Returns this request's request URI.
+     *
+     * @return this request's URI
+     */
+    public abstract URI uri();
+
+    /**
+     * Returns this request's {@link HttpClient}.
+     *
+     * @return this request's HttpClient
+     */
+    public abstract HttpClient client();
+
+    /**
+     * Returns the HTTP protocol version that this request will use or used.
+     *
+     * @return HTTP protocol version
+     */
+    public abstract HttpClient.Version version();
+
+    /**
+     * The (user-accessible) request headers that this request was (or will be)
+     * sent with.
+     *
+     * @return this request's HttpHeaders
+     */
+    public abstract HttpHeaders headers();
+
+    /**
+     * Returns a request processor whose body is the given String, converted
+     * using the {@link java.nio.charset.StandardCharsets#ISO_8859_1 ISO_8859_1}
+     * character set.
+     *
+     * @param body the String containing the body
+     * @return a BodyProcessor
+     */
+    public static BodyProcessor fromString(String body) {
+        return fromString(body, StandardCharsets.ISO_8859_1);
+    }
+
+    /**
+     * A request processor that takes data from the contents of a File.
+     *
+     * @param path the path to the file containing the body
+     * @return a BodyProcessor
+     */
+    public static BodyProcessor fromFile(Path path) {
+        FileChannel fc;
+        long size;
+
+        try {
+            fc = FileChannel.open(path);
+            size = fc.size();
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+
+        return new BodyProcessor() {
+            LongConsumer flow;
+
+            @Override
+            public long onRequestStart(HttpRequest hr, LongConsumer flow) {
+                // could return exact file length, but for now -1
+                this.flow = flow;
+                flow.accept(1);
+                if (size != 0) {
+                    return size;
+                } else {
+                    return -1;
+                }
+            }
+
+            @Override
+            public boolean onRequestBodyChunk(ByteBuffer buffer) throws IOException {
+                int n = fc.read(buffer);
+                if (n == -1) {
+                    fc.close();
+                    return true;
+                }
+                flow.accept(1);
+                return false;
+            }
+
+            @Override
+            public void onRequestError(Throwable t) {
+                try {
+                    fc.close();
+                } catch (IOException ex) {
+                    Log.logError(ex.toString());
+                }
+            }
+        };
+    }
+
+    /**
+     * Returns a request processor whose body is the given String, converted
+     * using the given character set.
+     *
+     * @param s the String containing the body
+     * @param charset the character set to convert the string to bytes
+     * @return a BodyProcessor
+     */
+    public static BodyProcessor fromString(String s, Charset charset) {
+        return fromByteArray(s.getBytes(charset));
+    }
+
+    /**
+     * Returns a request processor whose body is the given byte array.
+     *
+     * @param buf the byte array containing the body
+     * @return a BodyProcessor
+     */
+    public static BodyProcessor fromByteArray(byte[] buf) {
+        return fromByteArray(buf, 0, buf.length);
+    }
+
+    /**
+     * Returns a request processor whose body is the content of the given byte
+     * array length bytes starting from the specified offset.
+     *
+     * @param buf the byte array containing the body
+     * @param offset the offset of the first byte
+     * @param length the number of bytes to use
+     * @return a BodyProcessor
+     */
+    public static BodyProcessor fromByteArray(byte[] buf, int offset, int length) {
+
+        return new BodyProcessor() {
+            LongConsumer flow;
+            byte[] barray;
+            int index;
+            int sent;
+
+            @Override
+            public long onRequestStart(HttpRequest hr, LongConsumer flow) {
+                this.flow = flow;
+                flow.accept(1);
+                barray = buf;
+                index = offset;
+                return length;
+            }
+
+            @Override
+            public boolean onRequestBodyChunk(ByteBuffer buffer)
+                throws IOException
+            {
+                if (sent == length) {
+                    return true;
+                }
+
+                int remaining = buffer.remaining();
+                int left = length - sent;
+                int n = remaining > left ? left : remaining;
+                buffer.put(barray, index, n);
+                index += n;
+                sent += n;
+                flow.accept(1);
+                return sent == length;
+            }
+
+            @Override
+            public void onRequestError(Throwable t) {
+                Log.logError(t.toString());
+            }
+        };
+    }
+
+    /**
+     * A request processor that takes data from an Iterator of byte arrays.
+     *
+     * @param iter an Iterator of byte arrays
+     * @return a BodyProcessor
+     */
+    public static BodyProcessor fromByteArrays(Iterator<byte[]> iter) {
+
+        return new BodyProcessor() {
+            LongConsumer flow;
+            byte[] current;
+            int curIndex;
+
+            @Override
+            public long onRequestStart(HttpRequest hr, LongConsumer flow) {
+                this.flow = flow;
+                flow.accept(1);
+                return -1;
+            }
+
+            @Override
+            public boolean onRequestBodyChunk(ByteBuffer buffer)
+                throws IOException
+            {
+                int remaining;
+
+                while ((remaining = buffer.remaining()) > 0) {
+                    if (current == null) {
+                        if (!iter.hasNext()) {
+                            return true;
+                        }
+                        current = iter.next();
+                        curIndex = 0;
+                    }
+                    int n = Math.min(remaining, current.length - curIndex);
+                    buffer.put(current, curIndex, n);
+                    curIndex += n;
+
+                    if (curIndex == current.length) {
+                        current = null;
+                        flow.accept(1);
+                        return false;
+                    }
+                }
+                flow.accept(1);
+                return false;
+            }
+
+            @Override
+            public void onRequestError(Throwable t) {
+                Log.logError(t.toString());
+            }
+        };
+    }
+
+    /**
+     * A request processor that reads its data from an InputStream.
+     *
+     * @param stream an InputStream
+     * @return a BodyProcessor
+     */
+    public static BodyProcessor fromInputStream(InputStream stream) {
+        // for now, this blocks. It could be offloaded to a separate thread
+        // to do reading and guarantee that onRequestBodyChunk() won't block
+        return new BodyProcessor() {
+            LongConsumer flow;
+
+            @Override
+            public long onRequestStart(HttpRequest hr, LongConsumer flow) {
+                this.flow = flow;
+                flow.accept(1);
+                return -1;
+            }
+
+            @Override
+            public boolean onRequestBodyChunk(ByteBuffer buffer)
+                throws IOException
+            {
+                int remaining = buffer.remaining();
+                int n = stream.read(buffer.array(), buffer.arrayOffset(), remaining);
+                if (n == -1) {
+                    stream.close();
+                    return true;
+                }
+                buffer.position(buffer.position() + n);
+                flow.accept(1);
+                return false;
+            }
+
+            @Override
+            public void onRequestError(Throwable t) {
+                Log.logError(t.toString());
+            }
+        };
+    }
+
+    /**
+     * A request processor which sends no request body.
+     *
+     * @return a BodyProcessor
+     */
+    public static BodyProcessor noBody() {
+        return new BodyProcessor() {
+
+            @Override
+            public long onRequestStart(HttpRequest hr, LongConsumer flow) {
+                return 0;
+            }
+
+            @Override
+            public boolean onRequestBodyChunk(ByteBuffer buffer)
+                throws IOException
+            {
+                throw new InternalError("should never reach here");
+            }
+
+            @Override
+            public void onRequestError(Throwable t) {
+                Log.logError(t.toString());
+            }
+        };
+    }
+
+    /**
+     * A request processor which obtains the request body from some source.
+     * Implementations of this interface are provided which allow request bodies
+     * to be supplied from standard types, such as {@code String, byte[], File,
+     * InputStream}. Other implementations can be provided.
+     *
+     * <p> The methods of this interface may be called from multiple threads,
+     * but only one method is invoked at a time, and behaves as if called from
+     * one thread.
+     *
+     * <p> See {@link HttpRequest} for implementations that take request bodies
+     * from {@code byte arrays, Strings, Paths} etc.
+     *
+     * @since 9
+     */
+    public interface BodyProcessor {
+
+        /**
+         * Called before a request is sent. Is expected to return the content
+         * length of the request body. Zero means no content. Less than zero
+         * means an unknown positive content-length, and the body will be
+         * streamed.
+         *
+         * <p> The flowController object must be used to manage the flow of
+         * calls to {@link #onRequestBodyChunk(ByteBuffer)}. The typical usage
+         * for a non-blocking processor is to call it once inside
+         * onRequestStart() and once during each call to onRequestBodyChunk().
+         *
+         * @param hr the request
+         * @param flowController the HttpFlowController
+         * @return the content length
+         * @throws IOException if an I/O error occurs
+         */
+        long onRequestStart(HttpRequest hr, LongConsumer flowController)
+            throws IOException;
+
+        /**
+         * Called if sending a request body fails.
+         *
+         * @implSpec The default implementation does nothing.
+         *
+         * @param t the Throwable that caused the failure
+         */
+        default void onRequestError(Throwable t) { }
+
+        /**
+         * Called to obtain a buffer of data to send. The data must be placed
+         * in the provided buffer. The implementation should not block. The
+         * boolean return code notifies the protocol implementation if the
+         * supplied buffer is the final one (or not).
+         *
+         * @param buffer a ByteBuffer to write data into
+         * @return whether or not this is the last buffer
+         * @throws IOException if an I/O error occurs
+         */
+        boolean onRequestBodyChunk(ByteBuffer buffer) throws IOException;
+
+        /**
+         * Called when the request body has been completely sent.
+         *
+         * @implSpec The default implementation does nothing
+         */
+        default void onComplete() {
+            // TODO: need to call this
+        }
+    }
+}