001/*
002 * Copyright 2002-2019 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.web.reactive.socket.adapter;
018
019import java.nio.ByteBuffer;
020import java.nio.charset.StandardCharsets;
021import java.util.function.Function;
022
023import javax.websocket.CloseReason;
024import javax.websocket.Endpoint;
025import javax.websocket.EndpointConfig;
026import javax.websocket.PongMessage;
027import javax.websocket.Session;
028
029import org.springframework.core.io.buffer.DataBuffer;
030import org.springframework.lang.Nullable;
031import org.springframework.util.Assert;
032import org.springframework.web.reactive.socket.CloseStatus;
033import org.springframework.web.reactive.socket.WebSocketHandler;
034import org.springframework.web.reactive.socket.WebSocketMessage;
035import org.springframework.web.reactive.socket.WebSocketMessage.Type;
036import org.springframework.web.reactive.socket.WebSocketSession;
037
038/**
039 * Adapter for Java WebSocket API (JSR-356) that delegates events to a reactive
040 * {@link WebSocketHandler} and its session.
041 *
042 * @author Violeta Georgieva
043 * @author Rossen Stoyanchev
044 * @since 5.0
045 */
046public class StandardWebSocketHandlerAdapter extends Endpoint {
047
048        private final WebSocketHandler delegateHandler;
049
050        private Function<Session, StandardWebSocketSession> sessionFactory;
051
052        @Nullable
053        private StandardWebSocketSession delegateSession;
054
055
056        public StandardWebSocketHandlerAdapter(WebSocketHandler handler,
057                        Function<Session, StandardWebSocketSession> sessionFactory) {
058
059                Assert.notNull(handler, "WebSocketHandler is required");
060                Assert.notNull(sessionFactory, "'sessionFactory' is required");
061                this.delegateHandler = handler;
062                this.sessionFactory = sessionFactory;
063        }
064
065
066        @Override
067        public void onOpen(Session session, EndpointConfig config) {
068                this.delegateSession = this.sessionFactory.apply(session);
069                Assert.state(this.delegateSession != null, "No delegate session");
070
071                session.addMessageHandler(String.class, message -> {
072                        WebSocketMessage webSocketMessage = toMessage(message);
073                        this.delegateSession.handleMessage(webSocketMessage.getType(), webSocketMessage);
074                });
075                session.addMessageHandler(ByteBuffer.class, message -> {
076                        WebSocketMessage webSocketMessage = toMessage(message);
077                        this.delegateSession.handleMessage(webSocketMessage.getType(), webSocketMessage);
078                });
079                session.addMessageHandler(PongMessage.class, message -> {
080                        WebSocketMessage webSocketMessage = toMessage(message);
081                        this.delegateSession.handleMessage(webSocketMessage.getType(), webSocketMessage);
082                });
083
084                this.delegateHandler.handle(this.delegateSession)
085                                .checkpoint(session.getRequestURI() + " [StandardWebSocketHandlerAdapter]")
086                                .subscribe(this.delegateSession);
087        }
088
089        private <T> WebSocketMessage toMessage(T message) {
090                WebSocketSession session = this.delegateSession;
091                Assert.state(session != null, "Cannot create message without a session");
092                if (message instanceof String) {
093                        byte[] bytes = ((String) message).getBytes(StandardCharsets.UTF_8);
094                        return new WebSocketMessage(Type.TEXT, session.bufferFactory().wrap(bytes));
095                }
096                else if (message instanceof ByteBuffer) {
097                        DataBuffer buffer = session.bufferFactory().wrap((ByteBuffer) message);
098                        return new WebSocketMessage(Type.BINARY, buffer);
099                }
100                else if (message instanceof PongMessage) {
101                        DataBuffer buffer = session.bufferFactory().wrap(((PongMessage) message).getApplicationData());
102                        return new WebSocketMessage(Type.PONG, buffer);
103                }
104                else {
105                        throw new IllegalArgumentException("Unexpected message type: " + message);
106                }
107        }
108
109        @Override
110        public void onClose(Session session, CloseReason reason) {
111                if (this.delegateSession != null) {
112                        int code = reason.getCloseCode().getCode();
113                        this.delegateSession.handleClose(new CloseStatus(code, reason.getReasonPhrase()));
114                }
115        }
116
117        @Override
118        public void onError(Session session, Throwable exception) {
119                if (this.delegateSession != null) {
120                        this.delegateSession.handleError(exception);
121                }
122        }
123
124}