/*
* Copyright 2002-2014 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.sockjs.client;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import org.springframework.core.task.SimpleAsyncTaskExecutor;
import org.springframework.core.task.TaskExecutor;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.http.client.ClientHttpRequest;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.util.Assert;
import org.springframework.util.StreamUtils;
import org.springframework.util.concurrent.SettableListenableFuture;
import org.springframework.web.client.HttpServerErrorException;
import org.springframework.web.client.RequestCallback;
import org.springframework.web.client.ResponseExtractor;
import org.springframework.web.client.RestOperations;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.socket.CloseStatus;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.sockjs.frame.SockJsFrame;
/**
* An {@code XhrTransport} implementation that uses a
* {@link org.springframework.web.client.RestTemplate RestTemplate}.
*
* @author Rossen Stoyanchev
* @since 4.1
*/
public class RestTemplateXhrTransport extends AbstractXhrTransport implements XhrTransport {
private final RestOperations restTemplate;
private TaskExecutor taskExecutor = new SimpleAsyncTaskExecutor();
public RestTemplateXhrTransport() {
this(new RestTemplate());
}
public RestTemplateXhrTransport(RestOperations restTemplate) {
Assert.notNull(restTemplate, "'restTemplate' is required");
this.restTemplate = restTemplate;
}
/**
* Return the configured {@code RestTemplate}.
*/
public RestOperations getRestTemplate() {
return this.restTemplate;
}
/**
* Configure the {@code TaskExecutor} to use to execute XHR receive requests.
* <p>By default {@link org.springframework.core.task.SimpleAsyncTaskExecutor
* SimpleAsyncTaskExecutor} is configured which creates a new thread every
* time the transports connects.
*/
public void setTaskExecutor(TaskExecutor taskExecutor) {
Assert.notNull(this.taskExecutor);
this.taskExecutor = taskExecutor;
}
/**
* Return the configured {@code TaskExecutor}.
*/
public TaskExecutor getTaskExecutor() {
return this.taskExecutor;
}
@Override
public ResponseEntity<String> executeInfoRequestInternal(URI infoUrl) {
RequestCallback requestCallback = new XhrRequestCallback(getRequestHeaders());
return this.restTemplate.execute(infoUrl, HttpMethod.GET, requestCallback, textExtractor);
}
@Override
public ResponseEntity<String> executeSendRequestInternal(URI url, HttpHeaders headers, TextMessage message) {
RequestCallback requestCallback = new XhrRequestCallback(headers, message.getPayload());
return this.restTemplate.execute(url, HttpMethod.POST, requestCallback, textExtractor);
}
@Override
protected void connectInternal(final TransportRequest request, final WebSocketHandler handler,
final URI receiveUrl, final HttpHeaders handshakeHeaders, final XhrClientSockJsSession session,
final SettableListenableFuture<WebSocketSession> connectFuture) {
getTaskExecutor().execute(new Runnable() {
@Override
public void run() {
XhrRequestCallback requestCallback = new XhrRequestCallback(handshakeHeaders);
XhrRequestCallback requestCallbackAfterHandshake = new XhrRequestCallback(getRequestHeaders());
XhrReceiveExtractor responseExtractor = new XhrReceiveExtractor(session);
while (true) {
if (session.isDisconnected()) {
session.afterTransportClosed(null);
break;
}
try {
if (logger.isTraceEnabled()) {
logger.trace("Starting XHR receive request, url=" + receiveUrl);
}
getRestTemplate().execute(receiveUrl, HttpMethod.POST, requestCallback, responseExtractor);
requestCallback = requestCallbackAfterHandshake;
}
catch (Throwable ex) {
if (!connectFuture.isDone()) {
connectFuture.setException(ex);
}
else {
session.handleTransportError(ex);
session.afterTransportClosed(new CloseStatus(1006, ex.getMessage()));
}
break;
}
}
}
});
}
/**
* A simple ResponseExtractor that reads the body into a String.
*/
private final static ResponseExtractor<ResponseEntity<String>> textExtractor =
new ResponseExtractor<ResponseEntity<String>>() {
@Override
public ResponseEntity<String> extractData(ClientHttpResponse response) throws IOException {
if (response.getBody() == null) {
return new ResponseEntity<String>(response.getHeaders(), response.getStatusCode());
}
else {
String body = StreamUtils.copyToString(response.getBody(), SockJsFrame.CHARSET);
return new ResponseEntity<String>(body, response.getHeaders(), response.getStatusCode());
}
}
};
/**
* A RequestCallback to add the headers and (optionally) String content.
*/
private static class XhrRequestCallback implements RequestCallback {
private final HttpHeaders headers;
private final String body;
public XhrRequestCallback(HttpHeaders headers) {
this(headers, null);
}
public XhrRequestCallback(HttpHeaders headers, String body) {
this.headers = headers;
this.body = body;
}
@Override
public void doWithRequest(ClientHttpRequest request) throws IOException {
if (this.headers != null) {
request.getHeaders().putAll(this.headers);
}
if (this.body != null) {
StreamUtils.copy(this.body, SockJsFrame.CHARSET, request.getBody());
}
}
}
/**
* Splits the body of an HTTP response into SockJS frames and delegates those
* to an {@link XhrClientSockJsSession}.
*/
private class XhrReceiveExtractor implements ResponseExtractor<Object> {
private final XhrClientSockJsSession sockJsSession;
public XhrReceiveExtractor(XhrClientSockJsSession sockJsSession) {
this.sockJsSession = sockJsSession;
}
@Override
public Object extractData(ClientHttpResponse response) throws IOException {
if (!HttpStatus.OK.equals(response.getStatusCode())) {
throw new HttpServerErrorException(response.getStatusCode());
}
if (logger.isTraceEnabled()) {
logger.trace("XHR receive headers: " + response.getHeaders());
}
InputStream is = response.getBody();
ByteArrayOutputStream os = new ByteArrayOutputStream();
while (true) {
if (this.sockJsSession.isDisconnected()) {
if (logger.isDebugEnabled()) {
logger.debug("SockJS sockJsSession closed, closing response.");
}
response.close();
break;
}
int b = is.read();
if (b == -1) {
if (os.size() > 0) {
handleFrame(os);
}
if (logger.isTraceEnabled()) {
logger.trace("XHR receive completed");
}
break;
}
if (b == '\n') {
handleFrame(os);
}
else {
os.write(b);
}
}
return null;
}
private void handleFrame(ByteArrayOutputStream os) {
byte[] bytes = os.toByteArray();
os.reset();
String content = new String(bytes, SockJsFrame.CHARSET);
if (logger.isTraceEnabled()) {
logger.trace("XHR receive content: " + content);
}
if (!PRELUDE.equals(content)) {
this.sockJsSession.handleFrame(new String(bytes, SockJsFrame.CHARSET));
}
}
}
}