001/* 002 * Copyright 2002-2017 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.socket.sockjs.transport.session; 018 019import java.io.IOException; 020import java.util.Map; 021 022import org.springframework.http.server.ServerHttpRequest; 023import org.springframework.http.server.ServerHttpResponse; 024import org.springframework.util.Assert; 025import org.springframework.web.socket.WebSocketHandler; 026import org.springframework.web.socket.sockjs.SockJsTransportFailureException; 027import org.springframework.web.socket.sockjs.frame.SockJsFrame; 028import org.springframework.web.socket.sockjs.frame.SockJsMessageCodec; 029import org.springframework.web.socket.sockjs.transport.SockJsServiceConfig; 030 031/** 032 * A SockJS session for use with streaming HTTP transports. 033 * 034 * @author Rossen Stoyanchev 035 * @since 4.0 036 */ 037public abstract class StreamingSockJsSession extends AbstractHttpSockJsSession { 038 039 private int byteCount; 040 041 042 public StreamingSockJsSession(String sessionId, SockJsServiceConfig config, 043 WebSocketHandler wsHandler, Map<String, Object> attributes) { 044 045 super(sessionId, config, wsHandler, attributes); 046 } 047 048 049 /** 050 * @deprecated as of 4.2, since this method is no longer used. 051 */ 052 @Override 053 @Deprecated 054 protected boolean isStreaming() { 055 return true; 056 } 057 058 /** 059 * Get the prelude to write to the response before any other data. 060 * @since 4.2 061 */ 062 protected abstract byte[] getPrelude(ServerHttpRequest request); 063 064 065 @Override 066 protected void handleRequestInternal(ServerHttpRequest request, ServerHttpResponse response, 067 boolean initialRequest) throws IOException { 068 069 byte[] prelude = getPrelude(request); 070 Assert.state(prelude != null, "Prelude expected"); 071 response.getBody().write(prelude); 072 response.flush(); 073 074 if (initialRequest) { 075 writeFrame(SockJsFrame.openFrame()); 076 } 077 flushCache(); 078 } 079 080 @Override 081 protected void flushCache() throws SockJsTransportFailureException { 082 while (!getMessageCache().isEmpty()) { 083 String message = getMessageCache().poll(); 084 SockJsMessageCodec messageCodec = getSockJsServiceConfig().getMessageCodec(); 085 SockJsFrame frame = SockJsFrame.messageFrame(messageCodec, message); 086 writeFrame(frame); 087 088 this.byteCount += (frame.getContentBytes().length + 1); 089 if (logger.isTraceEnabled()) { 090 logger.trace(this.byteCount + " bytes written so far, " + 091 getMessageCache().size() + " more messages not flushed"); 092 } 093 if (this.byteCount >= getSockJsServiceConfig().getStreamBytesLimit()) { 094 logger.trace("Streamed bytes limit reached, recycling current request"); 095 resetRequest(); 096 this.byteCount = 0; 097 break; 098 } 099 } 100 scheduleHeartbeat(); 101 } 102 103}