001/* 002 * Copyright 2002-2018 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.lang.Nullable; 031import org.springframework.util.Assert; 032import org.springframework.util.concurrent.ListenableFuture; 033import org.springframework.web.socket.WebSocketExtension; 034import org.springframework.web.socket.WebSocketHandler; 035import org.springframework.web.socket.WebSocketHttpHeaders; 036import org.springframework.web.socket.WebSocketSession; 037import org.springframework.web.util.UriComponentsBuilder; 038 039/** 040 * Abstract base class for {@link WebSocketClient} implementations. 041 * 042 * @author Rossen Stoyanchev 043 * @since 4.0 044 */ 045public abstract class AbstractWebSocketClient implements WebSocketClient { 046 047 private static final Set<String> specialHeaders = new HashSet<>(); 048 049 static { 050 specialHeaders.add("cache-control"); 051 specialHeaders.add("connection"); 052 specialHeaders.add("host"); 053 specialHeaders.add("sec-websocket-extensions"); 054 specialHeaders.add("sec-websocket-key"); 055 specialHeaders.add("sec-websocket-protocol"); 056 specialHeaders.add("sec-websocket-version"); 057 specialHeaders.add("pragma"); 058 specialHeaders.add("upgrade"); 059 } 060 061 062 protected final Log logger = LogFactory.getLog(getClass()); 063 064 065 @Override 066 public ListenableFuture<WebSocketSession> doHandshake(WebSocketHandler webSocketHandler, 067 String uriTemplate, Object... uriVars) { 068 069 Assert.notNull(uriTemplate, "'uriTemplate' must not be null"); 070 URI uri = UriComponentsBuilder.fromUriString(uriTemplate).buildAndExpand(uriVars).encode().toUri(); 071 return doHandshake(webSocketHandler, null, uri); 072 } 073 074 @Override 075 public final ListenableFuture<WebSocketSession> doHandshake(WebSocketHandler webSocketHandler, 076 @Nullable WebSocketHttpHeaders headers, URI uri) { 077 078 Assert.notNull(webSocketHandler, "WebSocketHandler must not be null"); 079 assertUri(uri); 080 081 if (logger.isDebugEnabled()) { 082 logger.debug("Connecting to " + uri); 083 } 084 085 HttpHeaders headersToUse = new HttpHeaders(); 086 if (headers != null) { 087 headers.forEach((header, values) -> { 088 if (values != null && !specialHeaders.contains(header.toLowerCase())) { 089 headersToUse.put(header, values); 090 } 091 }); 092 } 093 094 List<String> subProtocols = 095 (headers != null ? headers.getSecWebSocketProtocol() : Collections.emptyList()); 096 List<WebSocketExtension> extensions = 097 (headers != null ? headers.getSecWebSocketExtensions() : Collections.emptyList()); 098 099 return doHandshakeInternal(webSocketHandler, headersToUse, uri, subProtocols, extensions, 100 Collections.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 the 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 the 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}