io.undertow.server.handlers.sse.ServerSentEventConnection Maven / Gradle / Ivy
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* Copyright 2014 Red Hat, Inc., and individual contributors
* as indicated by the @author tags.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package io.undertow.server.handlers.sse;
import io.undertow.UndertowLogger;
import io.undertow.connector.PooledByteBuffer;
import io.undertow.security.api.SecurityContext;
import io.undertow.security.idm.Account;
import io.undertow.server.HttpServerExchange;
import io.undertow.util.Attachable;
import io.undertow.util.AttachmentKey;
import io.undertow.util.AttachmentList;
import io.undertow.util.HeaderMap;
import org.xnio.ChannelExceptionHandler;
import org.xnio.ChannelListener;
import org.xnio.ChannelListeners;
import org.xnio.IoUtils;
import org.xnio.XnioExecutor;
import org.xnio.channels.StreamSinkChannel;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.Channel;
import java.nio.channels.ClosedChannelException;
import java.nio.charset.StandardCharsets;
import java.security.Principal;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Deque;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedDeque;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
/**
* Represents the server side of a Server Sent Events connection.
*
* The class implements Attachable, which provides access to the underlying exchanges attachments.
*
* @author Stuart Douglas
*/
public class ServerSentEventConnection implements Channel, Attachable {
private final HttpServerExchange exchange;
private final StreamSinkChannel sink;
private final SseWriteListener writeListener = new SseWriteListener();
private PooledByteBuffer pooled;
private final Deque queue = new ConcurrentLinkedDeque<>();
private final Queue buffered = new ConcurrentLinkedDeque<>();
/**
* Messages that have been written to the channel but flush() has failed
*/
private final Queue flushingMessages = new ArrayDeque<>();
private final List> closeTasks = new CopyOnWriteArrayList<>();
private Map parameters;
private Map properties = new HashMap<>();
private static final AtomicIntegerFieldUpdater openUpdater = AtomicIntegerFieldUpdater.newUpdater(ServerSentEventConnection.class, "open");
private volatile int open = 1;
private volatile boolean shutdown = false;
private volatile long keepAliveTime = -1;
private XnioExecutor.Key timerKey;
public ServerSentEventConnection(HttpServerExchange exchange, StreamSinkChannel sink) {
this.exchange = exchange;
this.sink = sink;
this.sink.getCloseSetter().set(new ChannelListener() {
@Override
public void handleEvent(StreamSinkChannel channel) {
if(timerKey != null) {
timerKey.remove();
}
for (ChannelListener listener : closeTasks) {
ChannelListeners.invokeChannelListener(ServerSentEventConnection.this, listener);
}
IoUtils.safeClose(ServerSentEventConnection.this);
}
});
this.sink.getWriteSetter().set(writeListener);
}
/**
* Adds a listener that will be invoked when the channel is closed
*
* @param listener The listener to invoke
*/
public synchronized void addCloseTask(ChannelListener listener) {
this.closeTasks.add(listener);
}
/**
*
* @return The principal that was associated with the SSE request
*/
public Principal getPrincipal() {
Account account = getAccount();
if (account != null) {
return account.getPrincipal();
}
return null;
}
/**
*
* @return The account that was associated with the SSE request
*/
public Account getAccount() {
SecurityContext sc = exchange.getSecurityContext();
if (sc != null) {
return sc.getAuthenticatedAccount();
}
return null;
}
/**
*
* @return The request headers from the initial request that opened this connection
*/
public HeaderMap getRequestHeaders() {
return exchange.getRequestHeaders();
}
/**
*
* @return The response headers from the initial request that opened this connection
*/
public HeaderMap getResponseHeaders() {
return exchange.getResponseHeaders();
}
/**
*
* @return The request URI from the initial request that opened this connection
*/
public String getRequestURI() {
return exchange.getRequestURI();
}
/**
*
* @return the query parameters
*/
public Map> getQueryParameters() {
return exchange.getQueryParameters();
}
/**
*
* @return the query string
*/
public String getQueryString() {
return exchange.getQueryString();
}
/**
* Sends an event to the remote client
*
* @param data The event data
*/
public void send(String data) {
send(data, null, null, null);
}
/**
* Sends an event to the remote client
*
* @param data The event data
* @param callback A callback that is notified on Success or failure
*/
public void send(String data, EventCallback callback) {
send(data, null, null, callback);
}
/**
* Sends the 'retry' message to the client, instructing it how long to wait before attempting a reconnect.
*
* @param retry The retry time in milliseconds
*/
public void sendRetry(long retry) {
sendRetry(retry, null);
}
/**
* Sends the 'retry' message to the client, instructing it how long to wait before attempting a reconnect.
*
* @param retry The retry time in milliseconds
* @param callback The callback that is notified on success or failure
*/
public synchronized void sendRetry(long retry, EventCallback callback) {
if (open == 0 || shutdown) {
if (callback != null) {
callback.failed(this, null, null, null, new ClosedChannelException());
}
return;
}
queue.add(new SSEData(retry, callback));
sink.getIoThread().execute(new Runnable() {
@Override
public void run() {
synchronized (ServerSentEventConnection.this) {
if (pooled == null) {
fillBuffer();
writeListener.handleEvent(sink);
}
}
}
});
}
/**
* Sends an event to the remote client
*
* @param data The event data
* @param event The event name
* @param id The event ID
* @param callback A callback that is notified on Success or failure
*/
public synchronized void send(String data, String event, String id, EventCallback callback) {
if (open == 0 || shutdown) {
if (callback != null) {
callback.failed(this, data, event, id, new ClosedChannelException());
}
return;
}
queue.add(new SSEData(event, data, id, callback));
sink.getIoThread().execute(new Runnable() {
@Override
public void run() {
synchronized (ServerSentEventConnection.this) {
if (pooled == null) {
fillBuffer();
writeListener.handleEvent(sink);
}
}
}
});
}
public String getParameter(String name) {
if(parameters == null) {
return null;
}
return parameters.get(name);
}
public void setParameter(String name, String value) {
if(parameters == null) {
parameters = new HashMap<>();
}
parameters.put(name, value);
}
public Map getProperties() {
return properties;
}
/**
*
*
* @return The keep alive time
*/
public long getKeepAliveTime() {
return keepAliveTime;
}
/**
* Sets the keep alive time in milliseconds. If this is larger than zero a ':' message will be sent this often
* (assuming there is no activity) to keep the connection alive.
*
* The spec recommends a value of 15000 (15 seconds).
*
* @param keepAliveTime The time in milliseconds between keep alive messaged
*/
public void setKeepAliveTime(long keepAliveTime) {
this.keepAliveTime = keepAliveTime;
if(this.timerKey != null) {
this.timerKey.remove();
}
this.timerKey = sink.getIoThread().executeAtInterval(new Runnable() {
@Override
public void run() {
if(shutdown || open == 0) {
if(timerKey != null) {
timerKey.remove();
}
return;
}
if(pooled == null) {
pooled = exchange.getConnection().getByteBufferPool().allocate();
pooled.getBuffer().put(":\n".getBytes(StandardCharsets.UTF_8));
pooled.getBuffer().flip();
writeListener.handleEvent(sink);
}
}
}, keepAliveTime, TimeUnit.MILLISECONDS);
}
private void fillBuffer() {
if (queue.isEmpty()) {
if(pooled != null) {
pooled.close();
pooled = null;
sink.suspendWrites();
}
return;
}
if (pooled == null) {
pooled = exchange.getConnection().getByteBufferPool().allocate();
} else {
pooled.getBuffer().clear();
}
ByteBuffer buffer = pooled.getBuffer();
while (!queue.isEmpty() && buffer.hasRemaining()) {
SSEData data = queue.poll();
buffered.add(data);
if (data.leftOverData == null) {
StringBuilder message = new StringBuilder();
if(data.retry > 0) {
message.append("retry:");
message.append(data.retry);
message.append('\n');
} else {
if (data.id != null) {
message.append("id:");
message.append(data.id);
message.append('\n');
}
if (data.event != null) {
message.append("event:");
message.append(data.event);
message.append('\n');
}
if (data.data != null) {
message.append("data:");
for (int i = 0; i < data.data.length(); ++i) {
char c = data.data.charAt(i);
if (c == '\n') {
message.append("\ndata:");
} else {
message.append(c);
}
}
message.append('\n');
}
}
message.append('\n');
byte[] messageBytes = message.toString().getBytes(StandardCharsets.UTF_8);
if (messageBytes.length < buffer.remaining()) {
buffer.put(messageBytes);
data.endBufferPosition = buffer.position();
} else {
queue.addFirst(data);
int rem = buffer.remaining();
buffer.put(messageBytes, 0, rem);
data.leftOverData = messageBytes;
data.leftOverDataOffset = rem;
}
} else {
int remainingData = data.leftOverData.length - data.leftOverDataOffset;
if (remainingData > buffer.remaining()) {
queue.addFirst(data);
int toWrite = buffer.remaining();
buffer.put(data.leftOverData, data.leftOverDataOffset, toWrite);
data.leftOverDataOffset += toWrite;
} else {
buffer.put(data.leftOverData, data.leftOverDataOffset, remainingData);
data.endBufferPosition = buffer.position();
data.leftOverData = null;
}
}
}
buffer.flip();
sink.resumeWrites();
}
/**
* execute a graceful shutdown once all data has been sent
*/
public void shutdown() {
if (open == 0 || shutdown) {
return;
}
shutdown = true;
sink.getIoThread().execute(new Runnable() {
@Override
public void run() {
synchronized (ServerSentEventConnection.this) {
if (queue.isEmpty() && pooled == null) {
exchange.endExchange();
}
}
}
});
}
@Override
public boolean isOpen() {
return open != 0;
}
@Override
public void close() throws IOException {
close(new ClosedChannelException());
}
private synchronized void close(IOException e) throws IOException {
if (openUpdater.compareAndSet(this, 1, 0)) {
if (pooled != null) {
pooled.close();
pooled = null;
}
List cb = new ArrayList<>(buffered.size() + queue.size() + flushingMessages.size());
cb.addAll(buffered);
cb.addAll(queue);
cb.addAll(flushingMessages);
queue.clear();
buffered.clear();
flushingMessages.clear();
for (SSEData i : cb) {
if (i.callback != null) {
try {
i.callback.failed(this, i.data, i.event, i.id, e);
} catch (Exception ex) {
UndertowLogger.REQUEST_LOGGER.failedToInvokeFailedCallback(i.callback, ex);
}
}
}
sink.shutdownWrites();
if(!sink.flush()) {
sink.getWriteSetter().set(ChannelListeners.flushingChannelListener(null, new ChannelExceptionHandler() {
@Override
public void handleException(StreamSinkChannel channel, IOException exception) {
IoUtils.safeClose(sink);
}
}));
sink.resumeWrites();
}
}
}
@Override
public T getAttachment(AttachmentKey key) {
return exchange.getAttachment(key);
}
@Override
public List getAttachmentList(AttachmentKey> key) {
return exchange.getAttachmentList(key);
}
@Override
public T putAttachment(AttachmentKey key, T value) {
return exchange.putAttachment(key, value);
}
@Override
public T removeAttachment(AttachmentKey key) {
return exchange.removeAttachment(key);
}
@Override
public void addToAttachmentList(AttachmentKey> key, T value) {
exchange.addToAttachmentList(key, value);
}
public interface EventCallback {
/**
* Notification that is called when a message is sucessfully sent
*
* @param connection The connection
* @param data The message data
* @param event The message event
* @param id The message id
*/
void done(ServerSentEventConnection connection, String data, String event, String id);
/**
* Notification that is called when a message send fails.
*
* @param connection The connection
* @param data The message data
* @param event The message event
* @param id The message id
* @param e The exception
*/
void failed(ServerSentEventConnection connection, String data, String event, String id, IOException e);
}
private static class SSEData {
final String event;
final String data;
final String id;
final long retry;
final EventCallback callback;
private int endBufferPosition = -1;
private byte[] leftOverData;
private int leftOverDataOffset;
private SSEData(String event, String data, String id, EventCallback callback) {
this.event = event;
this.data = data;
this.id = id;
this.callback = callback;
this.retry = -1;
}
private SSEData(long retry, EventCallback callback) {
this.event = null;
this.data = null;
this.id = null;
this.callback = callback;
this.retry = retry;
}
}
private class SseWriteListener implements ChannelListener {
@Override
public void handleEvent(StreamSinkChannel channel) {
synchronized (ServerSentEventConnection.this) {
try {
if (!flushingMessages.isEmpty()) {
if (!channel.flush()) {
return;
}
for (SSEData data : flushingMessages) {
if (data.callback != null && data.leftOverData == null) {
data.callback.done(ServerSentEventConnection.this, data.data, data.event, data.id);
}
}
flushingMessages.clear();
ByteBuffer buffer = pooled.getBuffer();
if (!buffer.hasRemaining()) {
fillBuffer();
if (pooled == null) {
if (channel.flush()) {
channel.suspendWrites();
}
return;
}
}
} else if (pooled == null) {
if (channel.flush()) {
channel.suspendWrites();
}
return;
}
ByteBuffer buffer = pooled.getBuffer();
int res;
do {
res = channel.write(buffer);
boolean flushed = channel.flush();
while (!buffered.isEmpty()) {
//figure out which messages are complete
SSEData data = buffered.peek();
if (data.endBufferPosition > 0 && buffer.position() >= data.endBufferPosition) {
buffered.poll();
if (flushed) {
if (data.callback != null && data.leftOverData == null) {
data.callback.done(ServerSentEventConnection.this, data.data, data.event, data.id);
}
} else {
//if flush was unsuccessful we defer the callback invocation, till it is actually on the wire
flushingMessages.add(data);
}
} else {
if (data.endBufferPosition <= 0) {
buffered.poll();
}
break;
}
}
if (!flushed && !flushingMessages.isEmpty()) {
sink.resumeWrites();
return;
}
if (!buffer.hasRemaining()) {
fillBuffer();
if (pooled == null) {
return;
}
} else if (res == 0) {
sink.resumeWrites();
return;
}
} while (res > 0);
} catch (IOException e) {
handleException(e);
}
}
}
}
private void handleException(IOException e) {
IoUtils.safeClose(this, sink, exchange.getConnection());
}
}
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