io.netty.handler.codec.http.websocketx.extensions.WebSocketServerExtensionHandler Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
/*
* Copyright 2014 The Netty Project
*
* The Netty Project licenses this file to you 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:
*
* https://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.netty.handler.codec.http.websocketx.extensions;
import static io.netty.util.internal.ObjectUtil.checkNonEmpty;
import io.netty.channel.ChannelDuplexHandler;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPromise;
import io.netty.handler.codec.http.HttpHeaderNames;
import io.netty.handler.codec.http.HttpHeaders;
import io.netty.handler.codec.http.HttpRequest;
import io.netty.handler.codec.http.HttpResponse;
import io.netty.handler.codec.http.HttpResponseStatus;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
/**
* This handler negotiates and initializes the WebSocket Extensions.
*
* It negotiates the extensions based on the client desired order,
* ensures that the successfully negotiated extensions are consistent between them,
* and initializes the channel pipeline with the extension decoder and encoder.
*
* Find a basic implementation for compression extensions at
* io.netty.handler.codec.http.websocketx.extensions.compression.WebSocketServerCompressionHandler.
*/
public class WebSocketServerExtensionHandler extends ChannelDuplexHandler {
private final List extensionHandshakers;
private List validExtensions;
/**
* Constructor
*
* @param extensionHandshakers
* The extension handshaker in priority order. A handshaker could be repeated many times
* with fallback configuration.
*/
public WebSocketServerExtensionHandler(WebSocketServerExtensionHandshaker... extensionHandshakers) {
this.extensionHandshakers = Arrays.asList(checkNonEmpty(extensionHandshakers, "extensionHandshakers"));
}
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
if (msg instanceof HttpRequest) {
HttpRequest request = (HttpRequest) msg;
if (WebSocketExtensionUtil.isWebsocketUpgrade(request.headers())) {
String extensionsHeader = request.headers().getAsString(HttpHeaderNames.SEC_WEBSOCKET_EXTENSIONS);
if (extensionsHeader != null) {
List extensions =
WebSocketExtensionUtil.extractExtensions(extensionsHeader);
int rsv = 0;
for (WebSocketExtensionData extensionData : extensions) {
Iterator extensionHandshakersIterator =
extensionHandshakers.iterator();
WebSocketServerExtension validExtension = null;
while (validExtension == null && extensionHandshakersIterator.hasNext()) {
WebSocketServerExtensionHandshaker extensionHandshaker =
extensionHandshakersIterator.next();
validExtension = extensionHandshaker.handshakeExtension(extensionData);
}
if (validExtension != null && ((validExtension.rsv() & rsv) == 0)) {
if (validExtensions == null) {
validExtensions = new ArrayList(1);
}
rsv = rsv | validExtension.rsv();
validExtensions.add(validExtension);
}
}
}
}
}
super.channelRead(ctx, msg);
}
@Override
public void write(final ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
if (msg instanceof HttpResponse) {
HttpResponse httpResponse = (HttpResponse) msg;
//checking the status is faster than looking at headers
//so we do this first
if (HttpResponseStatus.SWITCHING_PROTOCOLS.equals(httpResponse.status())) {
handlePotentialUpgrade(ctx, promise, httpResponse);
}
}
super.write(ctx, msg, promise);
}
private void handlePotentialUpgrade(final ChannelHandlerContext ctx,
ChannelPromise promise, HttpResponse httpResponse) {
HttpHeaders headers = httpResponse.headers();
if (WebSocketExtensionUtil.isWebsocketUpgrade(headers)) {
if (validExtensions != null) {
String headerValue = headers.getAsString(HttpHeaderNames.SEC_WEBSOCKET_EXTENSIONS);
List extraExtensions =
new ArrayList(extensionHandshakers.size());
for (WebSocketServerExtension extension : validExtensions) {
extraExtensions.add(extension.newReponseData());
}
String newHeaderValue = WebSocketExtensionUtil
.computeMergeExtensionsHeaderValue(headerValue, extraExtensions);
promise.addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) {
if (future.isSuccess()) {
for (WebSocketServerExtension extension : validExtensions) {
WebSocketExtensionDecoder decoder = extension.newExtensionDecoder();
WebSocketExtensionEncoder encoder = extension.newExtensionEncoder();
String name = ctx.name();
ctx.pipeline()
.addAfter(name, decoder.getClass().getName(), decoder)
.addAfter(name, encoder.getClass().getName(), encoder);
}
}
}
});
if (newHeaderValue != null) {
headers.set(HttpHeaderNames.SEC_WEBSOCKET_EXTENSIONS, newHeaderValue);
}
}
promise.addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) {
if (future.isSuccess()) {
ctx.pipeline().remove(WebSocketServerExtensionHandler.this);
}
}
});
}
}
}