/*
* Copyright 2002-2019 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
*
* https://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.sockjs.transport.handler;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.Map;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.util.StringUtils;
import org.springframework.web.socket.CloseStatus;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.sockjs.SockJsException;
import org.springframework.web.socket.sockjs.SockJsTransportFailureException;
import org.springframework.web.socket.sockjs.frame.DefaultSockJsFrameFormat;
import org.springframework.web.socket.sockjs.frame.SockJsFrameFormat;
import org.springframework.web.socket.sockjs.transport.SockJsServiceConfig;
import org.springframework.web.socket.sockjs.transport.SockJsSession;
import org.springframework.web.socket.sockjs.transport.TransportHandler;
import org.springframework.web.socket.sockjs.transport.TransportType;
import org.springframework.web.socket.sockjs.transport.session.AbstractHttpSockJsSession;
import org.springframework.web.socket.sockjs.transport.session.StreamingSockJsSession;
import org.springframework.web.util.JavaScriptUtils;
/**
* An HTTP {@link TransportHandler} that uses a famous browser
* {@code document.domain technique}. See
* stackoverflow.com/questions/1481251/what-does-document-domain-document-domain-do
* for details.
*
* @author Rossen Stoyanchev
* @since 4.0
*/
public class HtmlFileTransportHandler extends AbstractHttpSendingTransportHandler {
private static final String PARTIAL_HTML_CONTENT;
// Safari needs at least 1024 bytes to parse the website.
// https://code.google.com/p/browsersec/wiki/Part2#Survey_of_content_sniffing_behaviors
private static final int MINIMUM_PARTIAL_HTML_CONTENT_LENGTH = 1024;
static {
StringBuilder sb = new StringBuilder(
"\n" +
"\n" +
" \n" +
" \n" +
"Don't panic!
\n" +
" "
);
while (sb.length() < MINIMUM_PARTIAL_HTML_CONTENT_LENGTH) {
sb.append(" ");
}
PARTIAL_HTML_CONTENT = sb.toString();
}
@Override
public TransportType getTransportType() {
return TransportType.HTML_FILE;
}
@Override
protected MediaType getContentType() {
return new MediaType("text", "html", StandardCharsets.UTF_8);
}
@Override
public boolean checkSessionType(SockJsSession session) {
return (session instanceof HtmlFileStreamingSockJsSession);
}
@Override
public StreamingSockJsSession createSession(
String sessionId, WebSocketHandler handler, Map attributes) {
return new HtmlFileStreamingSockJsSession(sessionId, getServiceConfig(), handler, attributes);
}
@Override
public void handleRequestInternal(ServerHttpRequest request, ServerHttpResponse response,
AbstractHttpSockJsSession sockJsSession) throws SockJsException {
String callback = getCallbackParam(request);
if (!StringUtils.hasText(callback)) {
response.setStatusCode(HttpStatus.INTERNAL_SERVER_ERROR);
try {
response.getBody().write("\"callback\" parameter required".getBytes(StandardCharsets.UTF_8));
}
catch (IOException ex) {
sockJsSession.tryCloseWithSockJsTransportError(ex, CloseStatus.SERVER_ERROR);
throw new SockJsTransportFailureException("Failed to write to response", sockJsSession.getId(), ex);
}
return;
}
super.handleRequestInternal(request, response, sockJsSession);
}
@Override
protected SockJsFrameFormat getFrameFormat(ServerHttpRequest request) {
return new DefaultSockJsFrameFormat("\r\n") {
@Override
protected String preProcessContent(String content) {
return JavaScriptUtils.javaScriptEscape(content);
}
};
}
private class HtmlFileStreamingSockJsSession extends StreamingSockJsSession {
public HtmlFileStreamingSockJsSession(String sessionId, SockJsServiceConfig config,
WebSocketHandler wsHandler, Map attributes) {
super(sessionId, config, wsHandler, attributes);
}
@Override
protected byte[] getPrelude(ServerHttpRequest request) {
// We already validated the parameter above...
String callback = getCallbackParam(request);
String html = String.format(PARTIAL_HTML_CONTENT, callback);
return html.getBytes(StandardCharsets.UTF_8);
}
}
}