后台抛出异常如下：
Operator called default onErrorDropped
reactor.core.Exceptions$ErrorCallbackNotImplemented: java.lang.IllegalArgumentException: WebSocket close status code does NOT comply with RFC-6455: 1005
Caused by: java.lang.IllegalArgumentException: WebSocket close status code does NOT comply with RFC-6455: 1005
分析原因是：
spring cloud gateway 转发websocket请求无法监听到 close 事件 没有收到预期的状态码
解决方案：
在gateway进行请求拦截
代码如下：
@Slf4j
@Component
public class CustomWebsocketRoutingFilter implements GlobalFilter, Ordered {
//Sec-Websocket protocol
public static final String SEC_WEBSOCKET_PROTOCOL = "Sec-WebSocket-Protocol";
//Sec-Websocket header
public static final String SEC_WEBSOCKET_HEADER = "sec-websocket";
//http header schema
public static final String HEADER_UPGRADE_WebSocket = "websocket";
public static final String HEADER_UPGRADE_HTTP = "http";
public static final String HEADER_UPGRADE_HTTPS = "https";
private final WebSocketClient webSocketClient;
private final WebSocketService webSocketService;
private final ObjectProvider<List<HttpHeadersFilter>> headersFiltersProvider;
// 不直接使用 headersFilters 用该变量代替
private volatile List<HttpHeadersFilter> headersFilters;
public CustomWebsocketRoutingFilter(WebSocketClient webSocketClient, WebSocketService webSocketService, ObjectProvider<List<HttpHeadersFilter>> headersFiltersProvider) {
this.webSocketClient = webSocketClient;
this.webSocketService = webSocketService;
this.headersFiltersProvider = headersFiltersProvider;
}
/* for testing */
//http请求转为ws请求
static String convertHttpToWs(String scheme) {
scheme = scheme.toLowerCase();
return "http".equals(scheme) ? "ws" : "https".equals(scheme) ? "wss" : scheme;
}
@Override
public int getOrder() {
// Before NettyRoutingFilter since this routes certain http requests
//修改了这里 之前是-1 降低优先级
return Ordered.LOWEST_PRECEDENCE - 2;
}
@Override
public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
changeSchemeIfIsWebSocketUpgrade(exchange);
URI requestUrl = exchange.getRequiredAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR);
String scheme = requestUrl.getScheme();
if (ServerWebExchangeUtils.isAlreadyRouted(exchange) || (!"ws".equals(scheme) && !"wss".equals(scheme))) {
return chain.filter(exchange);
}
ServerWebExchangeUtils.setAlreadyRouted(exchange);
HttpHeaders headers = exchange.getRequest().getHeaders();
HttpHeaders filtered = HttpHeadersFilter.filterRequest(getHeadersFilters(), exchange);
List<String> protocols = getProtocols(headers);
return this.webSocketService.handleRequest(exchange, new ProxyWebSocketHandler(requestUrl, this.webSocketClient, filtered, protocols));
}
/* for testing */
//获取请求头里的协议信息
List<String> getProtocols(HttpHeaders headers) {
List<String> protocols = headers.get(SEC_WEBSOCKET_PROTOCOL);
if (protocols != null) {
ArrayList<String> updatedProtocols = new ArrayList<>();
for (int i = 0; i < protocols.size(); i++) {
String protocol = protocols.get(i);
updatedProtocols.addAll(Arrays.asList(StringUtils.tokenizeToStringArray(protocol, ",")));
}
protocols = updatedProtocols;
}
return protocols;
}
/* for testing */
List<HttpHeadersFilter> getHeadersFilters() {
if (this.headersFilters == null) {
this.headersFilters = this.headersFiltersProvider.getIfAvailable(ArrayList::new);
// remove host header unless specifically asked not to
this.headersFilters.add((headers, exchange) -> {
HttpHeaders filtered = new HttpHeaders();
filtered.addAll(headers);
filtered.remove(HttpHeaders.HOST);
boolean preserveHost = exchange.getAttributeOrDefault(ServerWebExchangeUtils.PRESERVE_HOST_HEADER_ATTRIBUTE, false);
if (preserveHost) {
String host = exchange.getRequest().getHeaders().getFirst(HttpHeaders.HOST);
filtered.add(HttpHeaders.HOST, host);
}
return filtered;
});
this.headersFilters.add((headers, exchange) -> {
HttpHeaders filtered = new HttpHeaders();
for (Map.Entry<String, List<String>> entry : headers.entrySet()) {
if (!entry.getKey().toLowerCase().startsWith(SEC_WEBSOCKET_HEADER)) {
filtered.addAll(entry.getKey(), entry.getValue());
}
}
return filtered;
});
}
return this.headersFilters;
}
static void changeSchemeIfIsWebSocketUpgrade(ServerWebExchange exchange) {
// 检查版本是否适合
URI requestUrl = exchange.getRequiredAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR);
String scheme = requestUrl.getScheme().toLowerCase();
String upgrade = exchange.getRequest().getHeaders().getUpgrade();
// change the scheme if the socket client send a "http" or "https"
if (HEADER_UPGRADE_WebSocket.equalsIgnoreCase(upgrade) && (HEADER_UPGRADE_HTTP.equals(scheme) || HEADER_UPGRADE_HTTPS.equals(scheme))) {
String wsScheme = convertHttpToWs(scheme);
boolean encoded = ServerWebExchangeUtils.containsEncodedParts(requestUrl);
URI wsRequestUrl = UriComponentsBuilder.fromUri(requestUrl).scheme(wsScheme).build(encoded).toUri();
exchange.getAttributes().put(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR, wsRequestUrl);
if (log.isTraceEnabled()) {
log.trace("changeSchemeTo:[" + wsRequestUrl + "]");
}
}
}
//自定义websocket处理方式
private static class ProxyWebSocketHandler implements WebSocketHandler {
private final WebSocketClient client;
private final URI url;
private final HttpHeaders headers;
private final List<String> subProtocols;
ProxyWebSocketHandler(URI url, WebSocketClient client, HttpHeaders headers, List<String> protocols) {
this.client = client;
this.url = url;
this.headers = headers;
if (protocols != null) {
this.subProtocols = protocols;
} else {
this.subProtocols = Collections.emptyList();
}
}
@Override
public List<String> getSubProtocols() {
return this.subProtocols;
}
@Override
public Mono<Void> handle(WebSocketSession session) {
return this.client.execute(this.url, this.headers, new WebSocketHandler() {
private CloseStatus adaptCloseStatus(CloseStatus closeStatus) {
int code = closeStatus.getCode();
if (code > 2999 && code < 5000) {
return closeStatus;
}
switch (code) {
case 1000:
//正常关闭
return closeStatus;
case 1001:
//服务器挂了或者页面跳转
return closeStatus;
case 1002:
//协议错误
return closeStatus;
case 1003:
//收到了不能处理的数据类型
return closeStatus;
case 1004:
// 预留关闭状态码
return CloseStatus.PROTOCOL_ERROR;
case 1005:
// 预留关闭状态码 期望收到状态码但是没有收到
return CloseStatus.PROTOCOL_ERROR;
case 1006:
// 预留关闭状态码 连接异常关闭
return CloseStatus.PROTOCOL_ERROR;
case 1007:
//收到的数据与实际的消息类型不匹配
return closeStatus;
case 1008:
//收到不符合规则的消息
return closeStatus;
case 1009:
//收到太大的不能处理的消息
return closeStatus;
case 1010:
//client希望server提供多个扩展，server没有返回相应的扩展信息
return closeStatus;
case 1011:
//server遇到不能完成的请求
return closeStatus;
case 1012:
// Not in RFC6455
// return CloseStatus.SERVICE_RESTARTED;
return CloseStatus.PROTOCOL_ERROR;
case 1013:
// Not in RFC6455
// return CloseStatus.SERVICE_OVERLOAD;
return CloseStatus.PROTOCOL_ERROR;
case 1015:
// 不能进行TLS握手 如：server证书不能验证
return CloseStatus.PROTOCOL_ERROR;
default:
return CloseStatus.PROTOCOL_ERROR;
}
}
/**
* send 发送传出消息
* receive 处理入站消息流
* doOnNext 对每条消息做什么
* zip 加入流
* then 返回接收完成时完成的Mono<Void>
*/
@Override
public Mono<Void> handle(WebSocketSession proxySession) {
Mono<Void> serverClose = proxySession.closeStatus().filter(__ -> session.isOpen())
.map(this::adaptCloseStatus)
.flatMap(session::close);
Mono<Void> proxyClose = session.closeStatus().filter(__ -> proxySession.isOpen())
.map(this::adaptCloseStatus)
.flatMap(proxySession::close);
// Use retain() for Reactor Netty
Mono<Void> proxySessionSend = proxySession
.send(session.receive().doOnNext(WebSocketMessage::retain));
Mono<Void> serverSessionSend = session
.send(proxySession.receive().doOnNext(WebSocketMessage::retain));
// Ensure closeStatus from one propagates to the other
Mono.when(serverClose, proxyClose).subscribe();
// Complete when both sessions are done
return Mono.zip(proxySessionSend, serverSessionSend).then();
}
@Override
public List<String> getSubProtocols() {
return CustomWebsocketRoutingFilter.ProxyWebSocketHandler.this.subProtocols;
}
});
}
}
}