001/* 002 * Copyright 2002-2016 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.client; 018 019import java.net.URI; 020import java.util.Collections; 021import java.util.HashSet; 022import java.util.List; 023import java.util.Map; 024import java.util.Set; 025 026import org.apache.commons.logging.Log; 027import org.apache.commons.logging.LogFactory; 028 029import org.springframework.http.HttpHeaders; 030import org.springframework.util.Assert; 031import org.springframework.util.concurrent.ListenableFuture; 032import org.springframework.web.socket.WebSocketExtension; 033import org.springframework.web.socket.WebSocketHandler; 034import org.springframework.web.socket.WebSocketHttpHeaders; 035import org.springframework.web.socket.WebSocketSession; 036import org.springframework.web.util.UriComponentsBuilder; 037 038/** 039 * Abstract base class for {@link WebSocketClient} implementations. 040 * 041 * @author Rossen Stoyanchev 042 * @since 4.0 043 */ 044public abstract class AbstractWebSocketClient implements WebSocketClient { 045 046 private static final Set<String> specialHeaders = new HashSet<String>(); 047 048 static { 049 specialHeaders.add("cache-control"); 050 specialHeaders.add("connection"); 051 specialHeaders.add("host"); 052 specialHeaders.add("sec-websocket-extensions"); 053 specialHeaders.add("sec-websocket-key"); 054 specialHeaders.add("sec-websocket-protocol"); 055 specialHeaders.add("sec-websocket-version"); 056 specialHeaders.add("pragma"); 057 specialHeaders.add("upgrade"); 058 } 059 060 061 protected final Log logger = LogFactory.getLog(getClass()); 062 063 064 @Override 065 public ListenableFuture<WebSocketSession> doHandshake(WebSocketHandler webSocketHandler, 066 String uriTemplate, Object... uriVars) { 067 068 Assert.notNull(uriTemplate, "'uriTemplate' must not be null"); 069 URI uri = UriComponentsBuilder.fromUriString(uriTemplate).buildAndExpand(uriVars).encode().toUri(); 070 return doHandshake(webSocketHandler, null, uri); 071 } 072 073 @Override 074 public final ListenableFuture<WebSocketSession> doHandshake(WebSocketHandler webSocketHandler, 075 WebSocketHttpHeaders headers, URI uri) { 076 077 Assert.notNull(webSocketHandler, "WebSocketHandler must not be null"); 078 assertUri(uri); 079 080 if (logger.isDebugEnabled()) { 081 logger.debug("Connecting to " + uri); 082 } 083 084 HttpHeaders headersToUse = new HttpHeaders(); 085 if (headers != null) { 086 for (String header : headers.keySet()) { 087 if (!specialHeaders.contains(header.toLowerCase())) { 088 headersToUse.put(header, headers.get(header)); 089 } 090 } 091 } 092 093 List<String> subProtocols = (headers != null && headers.getSecWebSocketProtocol() != null ? 094 headers.getSecWebSocketProtocol() : Collections.<String>emptyList()); 095 096 List<WebSocketExtension> extensions = (headers != null && headers.getSecWebSocketExtensions() != null ? 097 headers.getSecWebSocketExtensions() : Collections.<WebSocketExtension>emptyList()); 098 099 return doHandshakeInternal(webSocketHandler, headersToUse, uri, subProtocols, extensions, 100 Collections.<String, Object>emptyMap()); 101 } 102 103 protected void assertUri(URI uri) { 104 Assert.notNull(uri, "URI must not be null"); 105 String scheme = uri.getScheme(); 106 if (!"ws".equals(scheme) && !"wss".equals(scheme)) { 107 throw new IllegalArgumentException("Invalid scheme: " + scheme); 108 } 109 } 110 111 /** 112 * Perform the actual handshake to establish a connection to the server. 113 * @param webSocketHandler the client-side handler for WebSocket messages 114 * @param headers HTTP headers to use for the handshake, with unwanted (forbidden) 115 * headers filtered out, never {@code null} 116 * @param uri the target URI for the handshake, never {@code null} 117 * @param subProtocols requested sub-protocols, or an empty list 118 * @param extensions requested WebSocket extensions, or an empty list 119 * @param attributes attributes to associate with the WebSocketSession, i.e. via 120 * {@link WebSocketSession#getAttributes()}; currently always an empty map. 121 * @return the established WebSocket session wrapped in a ListenableFuture. 122 */ 123 protected abstract ListenableFuture<WebSocketSession> doHandshakeInternal(WebSocketHandler webSocketHandler, 124 HttpHeaders headers, URI uri, List<String> subProtocols, List<WebSocketExtension> extensions, 125 Map<String, Object> attributes); 126 127}