//
// ========================================================================
// Copyright (c) 1995-2017 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
//
package org.eclipse.jetty.http2.api;
import java.util.Collection;
import java.util.Map;
import org.eclipse.jetty.http2.frames.DataFrame;
import org.eclipse.jetty.http2.frames.GoAwayFrame;
import org.eclipse.jetty.http2.frames.HeadersFrame;
import org.eclipse.jetty.http2.frames.PingFrame;
import org.eclipse.jetty.http2.frames.PriorityFrame;
import org.eclipse.jetty.http2.frames.ResetFrame;
import org.eclipse.jetty.http2.frames.SettingsFrame;
import org.eclipse.jetty.util.Callback;
import org.eclipse.jetty.util.Promise;
/**
* <p>A {@link Session} represents the client-side endpoint of a HTTP/2 connection to a single origin server.</p>
* <p>Once a {@link Session} has been obtained, it can be used to open HTTP/2 streams:</p>
* <pre>
* Session session = ...;
* HeadersFrame frame = ...;
* Promise<Stream> promise = ...
* session.newStream(frame, promise, new Stream.Listener.Adapter()
* {
* public void onHeaders(Stream stream, HeadersFrame frame)
* {
* // Reply received
* }
* });
* </pre>
* <p>A {@link Session} is the active part of the endpoint, and by calling its API applications can generate
* events on the connection; conversely {@link Session.Listener} is the passive part of the endpoint, and
* has callbacks that are invoked when events happen on the connection.</p>
*
* @see Session.Listener
*/
public interface Session
{
/**
* <p>Sends the given HEADERS {@code frame} to create a new {@link Stream}.</p>
*
* @param frame the HEADERS frame containing the HTTP headers
* @param promise the promise that gets notified of the stream creation
* @param listener the listener that gets notified of stream events
*/
public void newStream(HeadersFrame frame, Promise<Stream> promise, Stream.Listener listener);
/**
* <p>Sends the given PRIORITY {@code frame}.</p>
* <p>If the {@code frame} references a {@code streamId} that does not exist
* (for example {@code 0}), then a new {@code streamId} will be allocated, to
* support <em>unused anchor streams</em> that act as parent for other streams.</p>
*
* @param frame the PRIORITY frame to send
* @param callback the callback that gets notified when the frame has been sent
* @return the new stream id generated by the PRIORITY frame, or the stream id
* that it is already referencing
*/
public int priority(PriorityFrame frame, Callback callback);
/**
* <p>Sends the given SETTINGS {@code frame} to configure the session.</p>
*
* @param frame the SETTINGS frame to send
* @param callback the callback that gets notified when the frame has been sent
*/
public void settings(SettingsFrame frame, Callback callback);
/**
* <p>Sends the given PING {@code frame}.</p>
* <p>PING frames may be used to test the connection integrity and to measure
* round-trip time.</p>
*
* @param frame the PING frame to send
* @param callback the callback that gets notified when the frame has been sent
*/
public void ping(PingFrame frame, Callback callback);
/**
* <p>Closes the session by sending a GOAWAY frame with the given error code
* and payload.</p>
* <p>The GOAWAY frame is sent only once; subsequent or concurrent attempts to
* close the session will have no effect.</p>
*
* @param error the error code
* @param payload an optional payload (may be null)
* @param callback the callback that gets notified when the frame has been sent
* @return true if the frame is being sent, false if the session was already closed
*/
public boolean close(int error, String payload, Callback callback);
/**
* @return whether the session is not open
*/
public boolean isClosed();
/**
* @return a snapshot of all the streams currently belonging to this session
*/
public Collection<Stream> getStreams();
/**
* <p>Retrieves the stream with the given {@code streamId}.</p>
*
* @param streamId the stream id of the stream looked for
* @return the stream with the given id, or null if no such stream exist
*/
public Stream getStream(int streamId);
/**
* <p>A {@link Listener} is the passive counterpart of a {@link Session} and
* receives events happening on a HTTP/2 connection.</p>
*
* @see Session
*/
public interface Listener
{
/**
* <p>Callback method invoked:</p>
* <ul>
* <li>for clients, just before the preface is sent, to gather the
* SETTINGS configuration options the client wants to send to the server;</li>
* <li>for servers, just after having received the preface, to gather
* the SETTINGS configuration options the server wants to send to the
* client.</li>
* </ul>
*
* @param session the session
* @return a (possibly empty or null) map containing SETTINGS configuration
* options to send.
*/
public Map<Integer, Integer> onPreface(Session session);
/**
* <p>Callback method invoked when a new stream is being created upon
* receiving a HEADERS frame representing a HTTP request.</p>
* <p>Applications should implement this method to process HTTP requests,
* typically providing a HTTP response via
* {@link Stream#headers(HeadersFrame, Callback)}.</p>
* <p>Applications can detect whether request DATA frames will be arriving
* by testing {@link HeadersFrame#isEndStream()}. If the application is
* interested in processing the DATA frames, it must return a
* {@link Stream.Listener} implementation that overrides
* {@link Stream.Listener#onData(Stream, DataFrame, Callback)}.</p>
*
* @param stream the newly created stream
* @param frame the HEADERS frame received
* @return a {@link Stream.Listener} that will be notified of stream events
*/
public Stream.Listener onNewStream(Stream stream, HeadersFrame frame);
/**
* <p>Callback method invoked when a SETTINGS frame has been received.</p>
*
* @param session the session
* @param frame the SETTINGS frame received
*/
public void onSettings(Session session, SettingsFrame frame);
/**
* <p>Callback method invoked when a PING frame has been received.</p>
*
* @param session the session
* @param frame the PING frame received
*/
public void onPing(Session session, PingFrame frame);
/**
* <p>Callback method invoked when a RST_STREAM frame has been received for an unknown stream.</p>
*
* @param session the session
* @param frame the RST_STREAM frame received
* @see Stream.Listener#onReset(Stream, ResetFrame)
*/
public void onReset(Session session, ResetFrame frame);
/**
* <p>Callback method invoked when a GOAWAY frame has been received.</p>
*
* @param session the session
* @param frame the GOAWAY frame received
*/
public void onClose(Session session, GoAwayFrame frame);
/**
* <p>Callback method invoked when the idle timeout expired.</p>
* @param session the session
* @return whether the session should be closed
*/
public boolean onIdleTimeout(Session session);
/**
* <p>Callback method invoked when a failure has been detected for this session.</p>
*
* @param session the session
* @param failure the failure
*/
public void onFailure(Session session, Throwable failure);
/**
* <p>Empty implementation of {@link Stream.Listener}.</p>
*/
public static class Adapter implements Session.Listener
{
@Override
public Map<Integer, Integer> onPreface(Session session)
{
return null;
}
@Override
public Stream.Listener onNewStream(Stream stream, HeadersFrame frame)
{
return null;
}
@Override
public void onSettings(Session session, SettingsFrame frame)
{
}
@Override
public void onPing(Session session, PingFrame frame)
{
}
@Override
public void onReset(Session session, ResetFrame frame)
{
}
@Override
public void onClose(Session session, GoAwayFrame frame)
{
}
@Override
public boolean onIdleTimeout(Session session)
{
return true;
}
@Override
public void onFailure(Session session, Throwable failure)
{
}
}
}
}