目录
协议
参考 https://www.cnblogs.com/nuccch/p/10947256.html
WebSocket是基于TCP的应用层协议，用于在C/S架构的应用中实现双向通信，关于WebSocket协议的详细规范和定义参见rfc6455。
需要特别注意的是：虽然WebSocket协议在建立连接时会使用HTTP协议，但这并意味着WebSocket协议是基于HTTP协议实现的
WebSocket与Http的区别
websocket应用层的连接协议有两种
- Handshake
- Message
连接（Handshake）
标准的websocket连接请求头需要包含
GET /xxx HTTP/1.1
# 主机。
Host: server.example.com
# 协议升级。
Upgrade: websocket
# 连接状态。
Connection: Upgrade
# websocket客户端生成的随机字符。
Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
# websocket协议的版本是13。
Sec-WebSocket-Version: 13
数据帧（Message）
WebSocket协议格式：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-------+-+-------------+-------------------------------+
|F|R|R|R| opcode|M| Payload len | Extended payload length |
|I|S|S|S| (4) |A| (7) | (16/64) |
|N|V|V|V| |S| | (if payload len==126/127) |
| |1|2|3| |K| | |
+-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
| Extended payload length continued, if payload len == 127 |
+ - - - - - - - - - - - - - - - +-------------------------------+
| |Masking-key, if MASK set to 1 |
+-------------------------------+-------------------------------+
| Masking-key (continued) | Payload Data |
+-------------------------------- - - - - - - - - - - - - - - - +
: Payload Data continued ... :
+ - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
| Payload Data continued ... |
+---------------------------------------------------------------+
webflux集成
-
继承WebSocketHandler
EchoWebSocketHandler继承WebSocketHandler
public class EchoWebSocketHandler implements WebSocketHandler { public EchoWebSocketHandler() { } @Override public Mono<Void> handle(WebSocketSession session) { // Use retain() for Reactor Netty return session.send(session.receive().doOnNext(WebSocketMessage::retain)); } } -
注册HandlerMapping
注册了 /echo 到 EchoWebSocketHandler 的映射
@Bean public HandlerMapping handlerMapping() { Map<String, WebSocketHandler> map = new HashMap<>(); map.put("/echo", new EchoWebSocketHandler()); SimpleUrlHandlerMapping mapping = new SimpleUrlHandlerMapping(); mapping.setUrlMap(map); return mapping; } -
注入WebSocketHandlerAdapter
@Bean WebSocketHandlerAdapter webSocketHandlerAdapter(){ return new WebSocketHandlerAdapter(); }
原理解析
1.DispatcherHandler
注入了SimpleUrlHandlerMapping和WebSocketHandlerAdapter，看下如何处理来自浏览器的请求
public Mono<Void> handle(ServerWebExchange exchange) {
if (this.handlerMappings == null) {
return createNotFoundError();
}
return Flux.fromIterable(this.handlerMappings)
.concatMap(mapping -> mapping.getHandler(exchange))
.next()
.switchIfEmpty(createNotFoundError())
.flatMap(handler -> invokeHandler(exchange, handler))
.flatMap(result -> handleResult(exchange, result));
}
- mapping.getHandler(exchange)返回EchoWebSocketHandler
- invokeHandler调用WebSocketHandlerAdapter处理EchoWebSocketHandler
2.WebSocketHandlerAdapter
supports方法判断EchoWebSocketHandler的返回结果为true
handle方法调用WebSocketService的handleRequest方法
@Override
public boolean supports(Object handler) {
return WebSocketHandler.class.isAssignableFrom(handler.getClass());
}
@Override
public Mono<HandlerResult> handle(ServerWebExchange exchange, Object handler) {
WebSocketHandler webSocketHandler = (WebSocketHandler) handler;
return getWebSocketService().handleRequest(exchange, webSocketHandler).then(Mono.empty());
}
3.WebSocketService
实现类为HandshakeWebSocketService
验证HTTP请求头
- GET 方法
- Upgrade: websocket
- Connection: Upgrade
- Sec-Websocket-Key: S7SmUANSlEG47sjuY9C2sg==
- Sec-Websocket-Protocol: （可选）
RequestUpgradeStrategy处理websocket请求升级,即将HTTP协议转为Websocket协议，后面的数据都通过WebSocket数据帧进行通信
public Mono<Void> handleRequest(ServerWebExchange exchange, WebSocketHandler handler) {
ServerHttpRequest request = exchange.getRequest();
HttpMethod method = request.getMethod();
HttpHeaders headers = request.getHeaders();
if (HttpMethod.GET != method) {
return Mono.error(new MethodNotAllowedException(
request.getMethodValue(), Collections.singleton(HttpMethod.GET)));
}
if (!"WebSocket".equalsIgnoreCase(headers.getUpgrade())) {
return handleBadRequest(exchange, "Invalid 'Upgrade' header: " + headers);
}
List<String> connectionValue = headers.getConnection();
if (!connectionValue.contains("Upgrade") && !connectionValue.contains("upgrade")) {
return handleBadRequest(exchange, "Invalid 'Connection' header: " + headers);
}
String key = headers.getFirst(SEC_WEBSOCKET_KEY);
if (key == null) {
return handleBadRequest(exchange, "Missing "Sec-WebSocket-Key" header");
}
String protocol = selectProtocol(headers, handler);
return initAttributes(exchange).flatMap(attributes ->
this.upgradeStrategy.upgrade(exchange, handler, protocol,
() -> createHandshakeInfo(exchange, request, protocol, attributes))
);
}
4.RequestUpgradeStrategy
Reactor Netty的实现类ReactorNettyRequestUpgradeStrategy
调用HttpServerOperations.sendWebsocket进一步处理
public Mono<Void> upgrade(ServerWebExchange exchange, WebSocketHandler handler,
@Nullable String subProtocol, Supplier<HandshakeInfo> handshakeInfoFactory) {
ServerHttpResponse response = exchange.getResponse();
HttpServerResponse reactorResponse = ((AbstractServerHttpResponse) response).getNativeResponse();
HandshakeInfo handshakeInfo = handshakeInfoFactory.get();
NettyDataBufferFactory bufferFactory = (NettyDataBufferFactory) response.bufferFactory();
return reactorResponse.sendWebsocket(subProtocol, this.maxFramePayloadLength,
(in, out) -> {
ReactorNettyWebSocketSession session =
new ReactorNettyWebSocketSession(
in, out, handshakeInfo, bufferFactory, this.maxFramePayloadLength);
return handler.handle(session);
});
}
握手信息HandshakeInfo
private HandshakeInfo createHandshakeInfo(ServerWebExchange exchange, ServerHttpRequest request,
@Nullable String protocol, Map<String, Object> attributes) {
URI uri = request.getURI();
// Copy request headers, as they might be pooled and recycled by
// the server implementation once the handshake HTTP exchange is done.
HttpHeaders headers = new HttpHeaders();
headers.addAll(request.getHeaders());
Mono<Principal> principal = exchange.getPrincipal();
String logPrefix = exchange.getLogPrefix();
InetSocketAddress remoteAddress = request.getRemoteAddress();
return new HandshakeInfo(uri, headers, principal, protocol, remoteAddress, attributes, logPrefix);
}
5.HttpServerOperations
- WebSocketServerOperations负责建立握手协议
- rebind 设置channel的ReactorNetty.CONNECTION属性为WebsocketServerOperations
- 成功后WebsocketHandler绑定WebsocketServerOperations
public Mono<Void> sendWebsocket(@Nullable String protocols, int maxFramePayloadLength, BiFunction<? super WebsocketInbound, ? super WebsocketOutbound, ? extends Publisher<Void>> websocketHandler) {
return this.withWebsocketSupport(this.uri(), protocols, maxFramePayloadLength, websocketHandler);
}
final Mono<Void> withWebsocketSupport(String url, @Nullable String protocols, int maxFramePayloadLength, BiFunction<? super WebsocketInbound, ? super WebsocketOutbound, ? extends Publisher<Void>> websocketHandler) {
Objects.requireNonNull(websocketHandler, "websocketHandler");
if (this.markSentHeaders()) {
WebsocketServerOperations ops = new WebsocketServerOperations(url, protocols, maxFramePayloadLength, this);
if (this.rebind(ops)) {
return FutureMono.from(ops.handshakerResult).doOnEach((signal) -> {
if (!signal.hasError() && (protocols == null || ops.selectedSubprotocol() != null)) {
((Publisher)websocketHandler.apply(ops, ops)).subscribe(new HttpServerOperations.WebsocketSubscriber(ops, signal.getContext()));
}
});
}
} else {
log.error(ReactorNetty.format(this.channel(), "Cannot enable websocket if headers have already been sent"));
}
return Mono.error(new IllegalStateException("Failed to upgrade to websocket"));
}
握手协议的建立
-
创建WebSocketServerHandshakerFactory
-
创建WebSocketServerHandshaker = WebSocketServerHandshakerFactory.newHandshaker
这里会根据sec-websocket-protocol加载相应的协议
public WebSocketServerHandshaker newHandshaker(HttpRequest req) { CharSequence version = req.headers().get(HttpHeaderNames.SEC_WEBSOCKET_VERSION); if (version != null) { if (version.equals(WebSocketVersion.V13.toHttpHeaderValue())) { return new WebSocketServerHandshaker13(this.webSocketURL, this.subprotocols, this.allowExtensions, this.maxFramePayloadLength, this.allowMaskMismatch); } else if (version.equals(WebSocketVersion.V08.toHttpHeaderValue())) { return new WebSocketServerHandshaker08(this.webSocketURL, this.subprotocols, this.allowExtensions, this.maxFramePayloadLength, this.allowMaskMismatch); } else { return version.equals(WebSocketVersion.V07.toHttpHeaderValue()) ? new WebSocketServerHandshaker07(this.webSocketURL, this.subprotocols, this.allowExtensions, this.maxFramePayloadLength, this.allowMaskMismatch) : null; } } else { return new WebSocketServerHandshaker00(this.webSocketURL, this.subprotocols, this.maxFramePayloadLength); } } -
移除reactor.left.httpTrafficHandler
-
WebSocketServerHandshaker.handshake实现握手
WebsocketServerOperations(String wsUrl, @Nullable String protocols, int maxFramePayloadLength, HttpServerOperations replaced) {
super(replaced);
Channel channel = replaced.channel();
WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory(wsUrl, protocols, true, maxFramePayloadLength);
this.handshaker = wsFactory.newHandshaker(replaced.nettyRequest);
if (this.handshaker == null) {
WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(channel);
this.handshakerResult = null;
} else {
this.removeHandler("reactor.left.httpTrafficHandler");
this.handshakerResult = channel.newPromise();
HttpRequest request = new DefaultFullHttpRequest(replaced.version(), replaced.method(), replaced.uri());
request.headers().set(replaced.nettyRequest.headers());
if (this.channel().pipeline().get("reactor.left.compressionHandler") != null) {
this.removeHandler("reactor.left.compressionHandler");
WebSocketServerCompressionHandler wsServerCompressionHandler = new WebSocketServerCompressionHandler();
try {
wsServerCompressionHandler.channelRead(channel.pipeline().context("reactor.right.reactiveBridge"), request);
this.addHandlerFirst("reactor.left.wsCompressionHandler", wsServerCompressionHandler);
} catch (Throwable var10) {
log.error(ReactorNetty.format(this.channel(), ""), var10);
}
}
this.handshaker.handshake(channel, request, replaced.responseHeaders.remove(HttpHeaderNames.TRANSFER_ENCODING), this.handshakerResult).addListener((f) -> {
this.markPersistent(false);
});
}
}
6.WebSocketServerHandshaker
实现类有WebSocketServerHandshaker13、WebSocketServerHandshaker08、WebSocketServerHandshaker07、WebSocketServerHandshaker00
-
新建HandshakeResponse
主要设置了三个Header
-
移除HttpObjectAggregator pipeline
-
移除HttpContentCompressor pipeline
-
在HttpServerCodec pipeline之前添加WebsocketDecoder和WebsocketEncoder
-
写HandshakeResponse到输出流
public final ChannelFuture handshake(Channel channel, FullHttpRequest req, HttpHeaders responseHeaders, final ChannelPromise promise) {
if (logger.isDebugEnabled()) {
logger.debug("{} WebSocket version {} server handshake", channel, this.version());
}
FullHttpResponse response = this.newHandshakeResponse(req, responseHeaders);
ChannelPipeline p = channel.pipeline();
if (p.get(HttpObjectAggregator.class) != null) {
p.remove(HttpObjectAggregator.class);
}
if (p.get(HttpContentCompressor.class) != null) {
p.remove(HttpContentCompressor.class);
}
ChannelHandlerContext ctx = p.context(HttpRequestDecoder.class);
final String encoderName;
if (ctx == null) {
ctx = p.context(HttpServerCodec.class);
if (ctx == null) {
promise.setFailure(new IllegalStateException("No HttpDecoder and no HttpServerCodec in the pipeline"));
return promise;
}
p.addBefore(ctx.name(), "wsdecoder", this.newWebsocketDecoder());
p.addBefore(ctx.name(), "wsencoder", this.newWebSocketEncoder());
encoderName = ctx.name();
} else {
p.replace(ctx.name(), "wsdecoder", this.newWebsocketDecoder());
encoderName = p.context(HttpResponseEncoder.class).name();
p.addBefore(encoderName, "wsencoder", this.newWebSocketEncoder());
}
channel.writeAndFlush(response).addListener(new ChannelFutureListener() {
public void operationComplete(ChannelFuture future) throws Exception {
if (future.isSuccess()) {
ChannelPipeline p = future.channel().pipeline();
p.remove(encoderName);
promise.setSuccess();
} else {
promise.setFailure(future.cause());
}
}
});
return promise;
}
握手前后的Netty Pipeline对比如下
注：WebSocketFrameAggregator是在org.springframework.web.reactive.socket.adapter.ReactorNettyWebSocketSession#receive方法中添加的
@Override
public Flux<WebSocketMessage> receive() {
return getDelegate().getInbound()
.aggregateFrames(this.maxFramePayloadLength)
.receiveFrames()
.map(super::toMessage)
.doOnNext(message -> {
if (logger.isTraceEnabled()) {
logger.trace(getLogPrefix() + "Received " + message);
}
});
}
default WebsocketInbound aggregateFrames(int maxContentLength) {
this.withConnection((c) -> {
c.addHandlerLast(new WebSocketFrameAggregator(maxContentLength));
});
return this;
}
7.WebsocketHandler绑定
reactor.netty.http.server.HttpServerOperations#withWebsocketSupport
FutureMono.from(ops.handshakerResult)
.doOnEach(signal -> {
if(!signal.hasError() && (protocols == null || ops.selectedSubprotocol() != null)) {
websocketHandler.apply(ops, ops)
.subscribe(new WebsocketSubscriber(ops, signal.getContext()));
}
});
websocketHandler.apply实际调用的是org.springframework.web.reactive.socket.server.upgrade.ReactorNettyRequestUpgradeStrategy#upgrade
(in, out) -> {
ReactorNettyWebSocketSession session =
new ReactorNettyWebSocketSession(
in, out, handshakeInfo, bufferFactory, this.maxFramePayloadLength);
return handler.handle(session);
})
handler的实际类是EchoWebSocketHandler
所以最终调用了
public Mono<Void> handle(WebSocketSession session) {
// Use retain() for Reactor Netty
return session.send(session.receive().doOnNext(WebSocketMessage::retain));
}
8.websocket解码
核心解码在WebSocket08FrameDecoder类
再来看下WebSocket协议格式：
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-------+-+-------------+-------------------------------+
|F|R|R|R| opcode|M| Payload len | Extended payload length |
|I|S|S|S| (4) |A| (7) | (16/64) |
|N|V|V|V| |S| | (if payload len==126/127) |
| |1|2|3| |K| | |
+-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
| Extended payload length continued, if payload len == 127 |
+ - - - - - - - - - - - - - - - +-------------------------------+
| |Masking-key, if MASK set to 1 |
+-------------------------------+-------------------------------+
| Masking-key (continued) | Payload Data |
+-------------------------------- - - - - - - - - - - - - - - - +
: Payload Data continued ... :
+ - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
| Payload Data continued ... |
+---------------------------------------------------------------+
- READING_FIRST 对应第一个字节的解析
- READING_SECOND 对应第二个字节的解析
- READING_SIZE 读取data payload长度
- MASKING_KEY masking-key 4个字节（需要READING_SECOND 的mask位为1）
- PAYLOAD 按长度去读payload到buffer
- 封装成TextWebSocketFrame,添加到out数组
protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
// Discard all data received if closing handshake was received before.
if (receivedClosingHandshake) {
in.skipBytes(actualReadableBytes());
return;
}
switch (state) {
case READING_FIRST:
if (!in.isReadable()) {
return;
}
framePayloadLength = 0;
// FIN, RSV, OPCODE
byte b = in.readByte();
frameFinalFlag = (b & 0x80) != 0;
frameRsv = (b & 0x70) >> 4;
frameOpcode = b & 0x0F;
if (logger.isDebugEnabled()) {
logger.debug("Decoding WebSocket Frame opCode={}", frameOpcode);
}
state = State.READING_SECOND;
case READING_SECOND:
if (!in.isReadable()) {
return;
}
// MASK, PAYLOAD LEN 1
b = in.readByte();
frameMasked = (b & 0x80) != 0;
framePayloadLen1 = b & 0x7F;
if (frameRsv != 0 && !allowExtensions) {
protocolViolation(ctx, "RSV != 0 and no extension negotiated, RSV:" + frameRsv);
return;
}
if (!allowMaskMismatch && expectMaskedFrames != frameMasked) {
protocolViolation(ctx, "received a frame that is not masked as expected");
return;
}
if (frameOpcode > 7) { // control frame (have MSB in opcode set)
// control frames MUST NOT be fragmented
if (!frameFinalFlag) {
protocolViolation(ctx, "fragmented control frame");
return;
}
// control frames MUST have payload 125 octets or less
if (framePayloadLen1 > 125) {
protocolViolation(ctx, "control frame with payload length > 125 octets");
return;
}
// check for reserved control frame opcodes
if (!(frameOpcode == OPCODE_CLOSE || frameOpcode == OPCODE_PING
|| frameOpcode == OPCODE_PONG)) {
protocolViolation(ctx, "control frame using reserved opcode " + frameOpcode);
return;
}
// close frame : if there is a body, the first two bytes of the
// body MUST be a 2-byte unsigned integer (in network byte
// order) representing a getStatus code
if (frameOpcode == 8 && framePayloadLen1 == 1) {
protocolViolation(ctx, "received close control frame with payload len 1");
return;
}
} else { // data frame
// check for reserved data frame opcodes
if (!(frameOpcode == OPCODE_CONT || frameOpcode == OPCODE_TEXT
|| frameOpcode == OPCODE_BINARY)) {
protocolViolation(ctx, "data frame using reserved opcode " + frameOpcode);
return;
}
// check opcode vs message fragmentation state 1/2
if (fragmentedFramesCount == 0 && frameOpcode == OPCODE_CONT) {
protocolViolation(ctx, "received continuation data frame outside fragmented message");
return;
}
// check opcode vs message fragmentation state 2/2
if (fragmentedFramesCount != 0 && frameOpcode != OPCODE_CONT && frameOpcode != OPCODE_PING) {
protocolViolation(ctx,
"received non-continuation data frame while inside fragmented message");
return;
}
}
state = State.READING_SIZE;
case READING_SIZE:
// Read frame payload length
if (framePayloadLen1 == 126) {
if (in.readableBytes() < 2) {
return;
}
framePayloadLength = in.readUnsignedShort();
if (framePayloadLength < 126) {
protocolViolation(ctx, "invalid data frame length (not using minimal length encoding)");
return;
}
} else if (framePayloadLen1 == 127) {
if (in.readableBytes() < 8) {
return;
}
framePayloadLength = in.readLong();
// TODO: check if it's bigger than 0x7FFFFFFFFFFFFFFF, Maybe
// just check if it's negative?
if (framePayloadLength < 65536) {
protocolViolation(ctx, "invalid data frame length (not using minimal length encoding)");
return;
}
} else {
framePayloadLength = framePayloadLen1;
}
if (framePayloadLength > maxFramePayloadLength) {
protocolViolation(ctx, "Max frame length of " + maxFramePayloadLength + " has been exceeded.");
return;
}
if (logger.isDebugEnabled()) {
logger.debug("Decoding WebSocket Frame length={}", framePayloadLength);
}
state = State.MASKING_KEY;
case MASKING_KEY:
if (frameMasked) {
if (in.readableBytes() < 4) {
return;
}
if (maskingKey == null) {
maskingKey = new byte[4];
}
in.readBytes(maskingKey);
}
state = State.PAYLOAD;
case PAYLOAD:
if (in.readableBytes() < framePayloadLength) {
return;
}
ByteBuf payloadBuffer = null;
try {
payloadBuffer = readBytes(ctx.alloc(), in, toFrameLength(framePayloadLength));
// Now we have all the data, the next checkpoint must be the next
// frame
state = State.READING_FIRST;
// Unmask data if needed
if (frameMasked) {
unmask(payloadBuffer);
}
// Processing ping/pong/close frames because they cannot be
// fragmented
if (frameOpcode == OPCODE_PING) {
out.add(new PingWebSocketFrame(frameFinalFlag, frameRsv, payloadBuffer));
payloadBuffer = null;
return;
}
if (frameOpcode == OPCODE_PONG) {
out.add(new PongWebSocketFrame(frameFinalFlag, frameRsv, payloadBuffer));
payloadBuffer = null;
return;
}
if (frameOpcode == OPCODE_CLOSE) {
receivedClosingHandshake = true;
checkCloseFrameBody(ctx, payloadBuffer);
out.add(new CloseWebSocketFrame(frameFinalFlag, frameRsv, payloadBuffer));
payloadBuffer = null;
return;
}
// Processing for possible fragmented messages for text and binary
// frames
if (frameFinalFlag) {
// Final frame of the sequence. Apparently ping frames are
// allowed in the middle of a fragmented message
if (frameOpcode != OPCODE_PING) {
fragmentedFramesCount = 0;
}
} else {
// Increment counter
fragmentedFramesCount++;
}
// Return the frame
if (frameOpcode == OPCODE_TEXT) {
out.add(new TextWebSocketFrame(frameFinalFlag, frameRsv, payloadBuffer));
payloadBuffer = null;
return;
} else if (frameOpcode == OPCODE_BINARY) {
out.add(new BinaryWebSocketFrame(frameFinalFlag, frameRsv, payloadBuffer));
payloadBuffer = null;
return;
} else if (frameOpcode == OPCODE_CONT) {
out.add(new ContinuationWebSocketFrame(frameFinalFlag, frameRsv,
payloadBuffer));
payloadBuffer = null;
return;
} else {
throw new UnsupportedOperationException("Cannot decode web socket frame with opcode: "
+ frameOpcode);
}
} finally {
if (payloadBuffer != null) {
payloadBuffer.release();
}
}
case CORRUPT:
if (in.isReadable()) {
// If we don't keep reading Netty will throw an exception saying
// we can't return null if no bytes read and state not changed.
in.readByte();
}
return;
default:
throw new Error("Shouldn't reach here.");
}
}
9.数据帧处理
接上面
-
wsdecoder处理后数据封装为TextWebSocketFrame
-
WebSocketFrameAggregator遍历TextWebSocketFrame数据，逐个发送到下一个pipeline处理
-
reactiveBridge的handler为ChannelOperationsHandler,调用ReactorNetty.CONNECTION绑定的Connection进行处理
reactor.netty.channel.ChannelOperationsHandler#channelRead
ChannelOperations<?, ?> ops = ChannelOperations.get(ctx.channel());
if (ops != null) {
ops.onInboundNext(ctx, msg);
}
实际调用为FluxReceive.onInboundNext
现在分析下FluxReceive对象是如何生成处理链的
com.example.demo.EchoWebSocketHandler#handle
@Override
public Mono<Void> handle(WebSocketSession session) {
// Use retain() for Reactor Netty
return session.send(session.receive().doOnNext(WebSocketMessage::retain));
}
org.springframework.web.reactive.socket.adapter.ReactorNettyWebSocketSession#receive
public Flux<WebSocketMessage> receive() {
return getDelegate().getInbound()
.aggregateFrames(this.maxFramePayloadLength)
.receiveFrames() // 1 FluxFilter 2 FluxMap
.map(super::toMessage) //3 FluxMap
.doOnNext(message -> { // 4 FluxPeek
if (logger.isTraceEnabled()) {
logger.trace(getLogPrefix() + "Received " + message);
}
});
}
com.example.demo.EchoWebSocketHandler#handle
session.receive().doOnNext(WebSocketMessage::retain) // doOnNext 5 FluxPeek
org.springframework.web.reactive.socket.adapter.ReactorNettyWebSocketSession#send
public Mono<Void> send(Publisher<WebSocketMessage> messages) {
Flux<WebSocketFrame> frames = Flux.from(messages)
.doOnNext(message -> { //6 FluxPeek
if (logger.isTraceEnabled()) {
logger.trace(getLogPrefix() + "Sending " + message);
}
})
.map(this::toFrame); //7 FluxMap
return getDelegate().getOutbound()
.options(NettyPipeline.SendOptions::flushOnEach)
.sendObject(frames) //8 MonoSendMany
.then();
}
reactor.netty.http.server.HttpServerOperations#withWebsocketSupport
websocketHandler.apply(ops, ops).subscribe(new WebsocketSubscriber(ops, signal.getContext()) //9 WebsocketSubscriber