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.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
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.DefaultHttpRequest;
import io.netty.handler.codec.http.DefaultHttpResponse;
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 io.netty.handler.codec.http.LastHttpContent;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Queue;
/**
* 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 final Queue> validExtensions =
new ArrayDeque>(4);
/**
* 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 {
// JDK type checks vs non-implemented interfaces costs O(N), where
// N is the number of interfaces already implemented by the concrete type that's being tested.
// The only requirement for this call is to make HttpRequest(s) implementors to call onHttpRequestChannelRead
// and super.channelRead the others, but due to the O(n) cost we perform few fast-path for commonly met
// singleton and/or concrete types, to save performing such slow type checks.
if (msg != LastHttpContent.EMPTY_LAST_CONTENT) {
if (msg instanceof DefaultHttpRequest) {
// fast-path
onHttpRequestChannelRead(ctx, (DefaultHttpRequest) msg);
} else if (msg instanceof HttpRequest) {
// slow path
onHttpRequestChannelRead(ctx, (HttpRequest) msg);
} else {
super.channelRead(ctx, msg);
}
} else {
super.channelRead(ctx, msg);
}
}
/**
* This is a method exposed to perform fail-fast checks of user-defined http types.
* eg:
* If the user has defined a specific {@link HttpRequest} type i.e.{@code CustomHttpRequest} and
* {@link #channelRead} can receive {@link LastHttpContent#EMPTY_LAST_CONTENT} {@code msg}
* types too, can override it like this:
*
* public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
* if (msg != LastHttpContent.EMPTY_LAST_CONTENT) {
* if (msg instanceof CustomHttpRequest) {
* onHttpRequestChannelRead(ctx, (CustomHttpRequest) msg);
* } else {
* // if it's handling other HttpRequest types it MUST use onHttpRequestChannelRead again
* // or have to delegate it to super.channelRead (that can perform redundant checks).
* // If msg is not implementing HttpRequest, it can call ctx.fireChannelRead(msg) on it
* // ...
* super.channelRead(ctx, msg);
* }
* } else {
* // given that msg isn't a HttpRequest type we can just skip calling super.channelRead
* ctx.fireChannelRead(msg);
* }
* }
*
* IMPORTANT:
* It already call {@code super.channelRead(ctx, request)} before returning.
*/
protected void onHttpRequestChannelRead(ChannelHandlerContext ctx, HttpRequest request) throws Exception {
List validExtensionsList = null;
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 (validExtensionsList == null) {
validExtensionsList = new ArrayList(1);
}
rsv = rsv | validExtension.rsv();
validExtensionsList.add(validExtension);
}
}
}
}
if (validExtensionsList == null) {
validExtensionsList = Collections.emptyList();
}
validExtensions.offer(validExtensionsList);
super.channelRead(ctx, request);
}
@Override
public void write(final ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
if (msg != Unpooled.EMPTY_BUFFER && !(msg instanceof ByteBuf)) {
if (msg instanceof DefaultHttpResponse) {
onHttpResponseWrite(ctx, (DefaultHttpResponse) msg, promise);
} else if (msg instanceof HttpResponse) {
onHttpResponseWrite(ctx, (HttpResponse) msg, promise);
} else {
super.write(ctx, msg, promise);
}
} else {
super.write(ctx, msg, promise);
}
}
/**
* This is a method exposed to perform fail-fast checks of user-defined http types.
* eg:
* If the user has defined a specific {@link HttpResponse} type i.e.{@code CustomHttpResponse} and
* {@link #write} can receive {@link ByteBuf} {@code msg} types too, it can be overridden like this:
*
* public void write(final ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
* if (msg != Unpooled.EMPTY_BUFFER && !(msg instanceof ByteBuf)) {
* if (msg instanceof CustomHttpResponse) {
* onHttpResponseWrite(ctx, (CustomHttpResponse) msg, promise);
* } else {
* // if it's handling other HttpResponse types it MUST use onHttpResponseWrite again
* // or have to delegate it to super.write (that can perform redundant checks).
* // If msg is not implementing HttpResponse, it can call ctx.write(msg, promise) on it
* // ...
* super.write(ctx, msg, promise);
* }
* } else {
* // given that msg isn't a HttpResponse type we can just skip calling super.write
* ctx.write(msg, promise);
* }
* }
*
* IMPORTANT:
* It already call {@code super.write(ctx, response, promise)} before returning.
*/
protected void onHttpResponseWrite(ChannelHandlerContext ctx, HttpResponse response, ChannelPromise promise)
throws Exception {
List validExtensionsList = validExtensions.poll();
// checking the status is faster than looking at headers so we do this first
if (HttpResponseStatus.SWITCHING_PROTOCOLS.equals(response.status())) {
handlePotentialUpgrade(ctx, promise, response, validExtensionsList);
}
super.write(ctx, response, promise);
}
private void handlePotentialUpgrade(final ChannelHandlerContext ctx,
ChannelPromise promise, HttpResponse httpResponse,
final List validExtensionsList) {
HttpHeaders headers = httpResponse.headers();
if (WebSocketExtensionUtil.isWebsocketUpgrade(headers)) {
if (validExtensionsList != null && !validExtensionsList.isEmpty()) {
String headerValue = headers.getAsString(HttpHeaderNames.SEC_WEBSOCKET_EXTENSIONS);
List extraExtensions =
new ArrayList(extensionHandshakers.size());
for (WebSocketServerExtension extension : validExtensionsList) {
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 : validExtensionsList) {
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);
}
}
});
}
}
}