/*
* Copyright 2012 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:
*
* 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.netty.handler.codec.http.websocketx;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.channel.ChannelPipeline;
import io.netty.handler.codec.http.DefaultFullHttpResponse;
import io.netty.handler.codec.http.FullHttpRequest;
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.ssl.SslHandler;
import static io.netty.handler.codec.http.HttpHeaders.*;
import static io.netty.handler.codec.http.HttpMethod.*;
import static io.netty.handler.codec.http.HttpResponseStatus.*;
import static io.netty.handler.codec.http.HttpVersion.*;
/**
* Handles the HTTP handshake (the HTTP Upgrade request) for {@link WebSocketServerProtocolHandler}.
*/
class WebSocketServerProtocolHandshakeHandler
extends ChannelInboundHandlerAdapter {
private final String websocketPath;
private final String subprotocols;
private final boolean allowExtensions;
public WebSocketServerProtocolHandshakeHandler(String websocketPath, String subprotocols,
boolean allowExtensions) {
this.websocketPath = websocketPath;
this.subprotocols = subprotocols;
this.allowExtensions = allowExtensions;
}
@Override
public void channelRead(final ChannelHandlerContext ctx, Object msg) throws Exception {
FullHttpRequest req = (FullHttpRequest) msg;
if (req.getMethod() != GET) {
sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, FORBIDDEN));
return;
}
final WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory(
getWebSocketLocation(ctx.pipeline(), req, websocketPath), subprotocols, allowExtensions);
/**
* 根据请求构建出WebSocketServerHandshaker的实例,该构造构成完成以下工作:
* 根据HttpRequest中header中解析出来的client支持的websocket的版本不同,构建出不同的子类实例:
* WebSocketServerHandshaker13,WebSocketServerHandshaker08,WebSocketServerHandshaker07,WebSocketServerHandshaker00
*2
*/
final WebSocketServerHandshaker handshaker = wsFactory.newHandshaker(req);
//如果工厂构建出的handshaker对象为null,那说明server端不支持client的websocket版本,发送UnsupportedWebSocketVersionResponse
if (handshaker == null) {
WebSocketServerHandshakerFactory.sendUnsupportedWebSocketVersionResponse(ctx.channel());
} else {
/**
* 如果支持,则进行握手操作:
*
*/
final ChannelFuture handshakeFuture = handshaker.handshake(ctx.channel(), req);
handshakeFuture.addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) throws Exception {
if (!future.isSuccess()) {
ctx.fireExceptionCaught(future.cause());
} else {
ctx.fireUserEventTriggered(
WebSocketServerProtocolHandler.ServerHandshakeStateEvent.HANDSHAKE_COMPLETE);
}
}
});
WebSocketServerProtocolHandler.setHandshaker(ctx, handshaker);
ctx.pipeline().replace(this, "WS403Responder",
WebSocketServerProtocolHandler.forbiddenHttpRequestResponder());
}
}
private static void sendHttpResponse(ChannelHandlerContext ctx, HttpRequest req, HttpResponse res) {
ChannelFuture f = ctx.channel().writeAndFlush(res);
if (!isKeepAlive(req) || res.getStatus().code() != 200) {
f.addListener(ChannelFutureListener.CLOSE);
}
}
private static String getWebSocketLocation(ChannelPipeline cp, HttpRequest req, String path) {
String protocol = "ws";
if (cp.get(SslHandler.class) != null) {
// SSL in use so use Secure WebSockets
protocol = "wss";
}
return protocol + "://" + req.headers().get(HttpHeaders.Names.HOST) + path;
}
}