/*
* Copyright 2014 Jeanfrancois Arcand
*
* 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.atmosphere.interceptor;
import org.atmosphere.cpr.Action;
import org.atmosphere.cpr.AsyncIOInterceptorAdapter;
import org.atmosphere.cpr.AsyncIOWriter;
import org.atmosphere.cpr.AtmosphereInterceptorAdapter;
import org.atmosphere.cpr.AtmosphereInterceptorWriter;
import org.atmosphere.cpr.AtmosphereRequest;
import org.atmosphere.cpr.AtmosphereResource;
import org.atmosphere.cpr.AtmosphereResource.TRANSPORT;
import org.atmosphere.cpr.AtmosphereResourceEvent;
import org.atmosphere.cpr.AtmosphereResourceEventListenerAdapter;
import org.atmosphere.cpr.AtmosphereResponse;
import org.atmosphere.cpr.FrameworkConfig;
import org.atmosphere.cpr.HeaderConfig;
import org.atmosphere.util.Utils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import static org.atmosphere.cpr.FrameworkConfig.INJECTED_ATMOSPHERE_RESOURCE;
/**
* Padding interceptor for Browser that needs whitespace when streaming is used.
*
* @author Jeanfrancois Arcand
*/
public class PaddingAtmosphereInterceptor extends AtmosphereInterceptorAdapter {
private static final Logger logger = LoggerFactory.getLogger(PaddingAtmosphereInterceptor.class);
private final byte[] padding;
private final String paddingText;
public PaddingAtmosphereInterceptor(){
paddingText = confPadding(2048);
padding = paddingText.getBytes();
}
public PaddingAtmosphereInterceptor(int size){
paddingText = confPadding(size);
padding = paddingText.getBytes();
}
protected final static String confPadding(int size) {
StringBuilder whitespace = new StringBuilder();
for (int i = 0; i < size; i++) {
whitespace.append(" ");
}
whitespace.append("\n");
return whitespace.toString();
}
private void writePadding(AtmosphereResponse response) {
AtmosphereRequest request = response.request();
if (request != null && request.getAttribute("paddingWritten") != null) return;
if (response.resource() != null && response.resource().transport().equals(TRANSPORT.STREAMING)) {
request.setAttribute(FrameworkConfig.TRANSPORT_IN_USE, HeaderConfig.STREAMING_TRANSPORT);
response.setContentType("text/plain");
}
response.write(padding, true);
try {
response.flushBuffer();
} catch (IOException e) {
logger.trace("", e);
}
}
@Override
public Action inspect(final AtmosphereResource r) {
if (Utils.webSocketMessage(r)) return Action.CONTINUE;
final AtmosphereResponse response = r.getResponse();
final AtmosphereRequest request = r.getRequest();
String uuid = request.getHeader(HeaderConfig.X_ATMOSPHERE_TRACKING_ID);
boolean padding = r.transport().equals(TRANSPORT.STREAMING) || r.transport().equals(TRANSPORT.LONG_POLLING);
if (uuid != null
&& !uuid.equals("0")
&& r.transport().equals(TRANSPORT.WEBSOCKET)
&& request.getAttribute(INJECTED_ATMOSPHERE_RESOURCE) != null) {
padding = true;
}
if (padding) {
r.addEventListener(new ForcePreSuspend(response));
super.inspect(r);
AsyncIOWriter writer = response.getAsyncIOWriter();
if (AtmosphereInterceptorWriter.class.isAssignableFrom(writer.getClass())) {
AtmosphereInterceptorWriter.class.cast(writer).interceptor(new AsyncIOInterceptorAdapter() {
private void padding() {
if (!r.isSuspended()) {
writePadding(response);
request.setAttribute("paddingWritten", "true");
}
}
@Override
public void prePayload(AtmosphereResponse response, byte[] data, int offset, int length) {
padding();
}
@Override
public void postPayload(AtmosphereResponse response, byte[] data, int offset, int length) {
}
});
} else {
logger.warn("Unable to apply {}. Your AsyncIOWriter must implement {}", getClass().getName(), AtmosphereInterceptorWriter.class.getName());
}
}
return Action.CONTINUE;
}
@Override
public String toString() {
return "Browser Padding Interceptor Support";
}
public final class ForcePreSuspend extends AtmosphereResourceEventListenerAdapter implements AllowInterceptor {
private final AtmosphereResponse response;
public ForcePreSuspend(AtmosphereResponse response) {
this.response = response;
}
@Override
public void onPreSuspend(AtmosphereResourceEvent event) {
writePadding(response);
event.getResource().removeEventListener(this);
}
}
}