/*
* Copyright 2002-2016 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.web.socket.client;
import java.net.URI;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.http.HttpHeaders;
import org.springframework.util.Assert;
import org.springframework.util.concurrent.ListenableFuture;
import org.springframework.web.socket.WebSocketExtension;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.WebSocketHttpHeaders;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.util.UriComponentsBuilder;
/**
* Abstract base class for {@link WebSocketClient} implementations.
*
* @author Rossen Stoyanchev
* @since 4.0
*/
public abstract class AbstractWebSocketClient implements WebSocketClient {
private static final Set<String> specialHeaders = new HashSet<>();
static {
specialHeaders.add("cache-control");
specialHeaders.add("connection");
specialHeaders.add("host");
specialHeaders.add("sec-websocket-extensions");
specialHeaders.add("sec-websocket-key");
specialHeaders.add("sec-websocket-protocol");
specialHeaders.add("sec-websocket-version");
specialHeaders.add("pragma");
specialHeaders.add("upgrade");
}
protected final Log logger = LogFactory.getLog(getClass());
@Override
public ListenableFuture<WebSocketSession> doHandshake(WebSocketHandler webSocketHandler,
String uriTemplate, Object... uriVars) {
Assert.notNull(uriTemplate, "'uriTemplate' must not be null");
URI uri = UriComponentsBuilder.fromUriString(uriTemplate).buildAndExpand(uriVars).encode().toUri();
return doHandshake(webSocketHandler, null, uri);
}
@Override
public final ListenableFuture<WebSocketSession> doHandshake(WebSocketHandler webSocketHandler,
WebSocketHttpHeaders headers, URI uri) {
Assert.notNull(webSocketHandler, "WebSocketHandler must not be null");
assertUri(uri);
if (logger.isDebugEnabled()) {
logger.debug("Connecting to " + uri);
}
HttpHeaders headersToUse = new HttpHeaders();
if (headers != null) {
for (String header : headers.keySet()) {
if (!specialHeaders.contains(header.toLowerCase())) {
headersToUse.put(header, headers.get(header));
}
}
}
List<String> subProtocols = (headers != null && headers.getSecWebSocketProtocol() != null ?
headers.getSecWebSocketProtocol() : Collections.emptyList());
List<WebSocketExtension> extensions = (headers != null && headers.getSecWebSocketExtensions() != null ?
headers.getSecWebSocketExtensions() : Collections.emptyList());
return doHandshakeInternal(webSocketHandler, headersToUse, uri, subProtocols, extensions,
Collections.emptyMap());
}
protected void assertUri(URI uri) {
Assert.notNull(uri, "URI must not be null");
String scheme = uri.getScheme();
if (!"ws".equals(scheme) && !"wss".equals(scheme)) {
throw new IllegalArgumentException("Invalid scheme: " + scheme);
}
}
/**
* Perform the actual handshake to establish a connection to the server.
* @param webSocketHandler the client-side handler for WebSocket messages
* @param headers HTTP headers to use for the handshake, with unwanted (forbidden)
* headers filtered out, never {@code null}
* @param uri the target URI for the handshake, never {@code null}
* @param subProtocols requested sub-protocols, or an empty list
* @param extensions requested WebSocket extensions, or an empty list
* @param attributes attributes to associate with the WebSocketSession, i.e. via
* {@link WebSocketSession#getAttributes()}; currently always an empty map.
* @return the established WebSocket session wrapped in a ListenableFuture.
*/
protected abstract ListenableFuture<WebSocketSession> doHandshakeInternal(WebSocketHandler webSocketHandler,
HttpHeaders headers, URI uri, List<String> subProtocols, List<WebSocketExtension> extensions,
Map<String, Object> attributes);
}