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/*
* Copyright (c) 2014, 2015 Cisco Systems, Inc. and others. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/epl-v10.html
*/
package org.opendaylight.netconf.sal.streams.websockets;
import static io.netty.handler.codec.http.HttpHeaderNames.HOST;
import static io.netty.handler.codec.http.HttpMethod.GET;
import static io.netty.handler.codec.http.HttpResponseStatus.BAD_REQUEST;
import static io.netty.handler.codec.http.HttpResponseStatus.FORBIDDEN;
import static io.netty.handler.codec.http.HttpResponseStatus.INTERNAL_SERVER_ERROR;
import static io.netty.handler.codec.http.HttpResponseStatus.OK;
import static io.netty.handler.codec.http.HttpUtil.isKeepAlive;
import static io.netty.handler.codec.http.HttpUtil.setContentLength;
import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.DefaultFullHttpResponse;
import io.netty.handler.codec.http.FullHttpRequest;
import io.netty.handler.codec.http.FullHttpResponse;
import io.netty.handler.codec.http.HttpRequest;
import io.netty.handler.codec.http.websocketx.CloseWebSocketFrame;
import io.netty.handler.codec.http.websocketx.PingWebSocketFrame;
import io.netty.handler.codec.http.websocketx.PongWebSocketFrame;
import io.netty.handler.codec.http.websocketx.WebSocketFrame;
import io.netty.handler.codec.http.websocketx.WebSocketServerHandshaker;
import io.netty.handler.codec.http.websocketx.WebSocketServerHandshakerFactory;
import io.netty.util.CharsetUtil;
import java.util.List;
import org.opendaylight.netconf.sal.restconf.impl.RestconfImpl;
import org.opendaylight.netconf.sal.streams.listeners.ListenerAdapter;
import org.opendaylight.netconf.sal.streams.listeners.NotificationListenerAdapter;
import org.opendaylight.netconf.sal.streams.listeners.Notificator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* {@link WebSocketServerHandler} is implementation of {@link SimpleChannelInboundHandler} which allow handle
* {@link FullHttpRequest} and {@link WebSocketFrame} messages.
*/
public class WebSocketServerHandler extends SimpleChannelInboundHandler<Object> {
private static final Logger LOG = LoggerFactory.getLogger(WebSocketServerHandler.class);
private WebSocketServerHandshaker handshaker;
@Override
protected void channelRead0(final ChannelHandlerContext ctx, final Object msg) {
if (msg instanceof FullHttpRequest) {
handleHttpRequest(ctx, (FullHttpRequest) msg);
} else if (msg instanceof WebSocketFrame) {
handleWebSocketFrame(ctx, (WebSocketFrame) msg);
}
}
/**
* Checks if HTTP request method is GET and if is possible to decode HTTP result of request.
*
* @param ctx ChannelHandlerContext
* @param req FullHttpRequest
*/
private void handleHttpRequest(final ChannelHandlerContext ctx, final FullHttpRequest req) {
// Handle a bad request.
if (!req.decoderResult().isSuccess()) {
sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, BAD_REQUEST));
return;
}
// Allow only GET methods.
if (req.method() != GET) {
sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, FORBIDDEN));
return;
}
final String streamName = Notificator.createStreamNameFromUri(req.uri());
if (streamName.contains(RestconfImpl.DATA_SUBSCR)) {
final ListenerAdapter listener = Notificator.getListenerFor(streamName);
if (listener != null) {
listener.addSubscriber(ctx.channel());
LOG.debug("Subscriber successfully registered.");
} else {
LOG.error("Listener for stream with name '{}' was not found.", streamName);
sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, INTERNAL_SERVER_ERROR));
}
} else if (streamName.contains(RestconfImpl.NOTIFICATION_STREAM)) {
final List<NotificationListenerAdapter> listeners = Notificator.getNotificationListenerFor(streamName);
if (listeners != null && !listeners.isEmpty()) {
for (final NotificationListenerAdapter listener : listeners) {
listener.addSubscriber(ctx.channel());
LOG.debug("Subscriber successfully registered.");
}
} else {
LOG.error("Listener for stream with name '{}' was not found.", streamName);
sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, INTERNAL_SERVER_ERROR));
}
}
// Handshake
final WebSocketServerHandshakerFactory wsFactory =
new WebSocketServerHandshakerFactory(getWebSocketLocation(req),
null, false);
this.handshaker = wsFactory.newHandshaker(req);
if (this.handshaker == null) {
WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(ctx.channel());
} else {
this.handshaker.handshake(ctx.channel(), req);
}
}
/**
* Checks response status, send response and close connection if necessary.
*
* @param ctx ChannelHandlerContext
* @param req HttpRequest
* @param res FullHttpResponse
*/
private static void sendHttpResponse(final ChannelHandlerContext ctx, final HttpRequest req,
final FullHttpResponse res) {
// Generate an error page if response getStatus code is not OK (200).
final boolean notOkay = !OK.equals(res.status());
if (notOkay) {
res.content().writeCharSequence(res.status().toString(), CharsetUtil.UTF_8);
setContentLength(res, res.content().readableBytes());
}
// Send the response and close the connection if necessary.
final ChannelFuture f = ctx.channel().writeAndFlush(res);
if (notOkay || !isKeepAlive(req)) {
f.addListener(ChannelFutureListener.CLOSE);
}
}
/**
* Handles web socket frame.
*
* @param ctx {@link ChannelHandlerContext}
* @param frame {@link WebSocketFrame}
*/
private void handleWebSocketFrame(final ChannelHandlerContext ctx, final WebSocketFrame frame) {
if (frame instanceof CloseWebSocketFrame) {
this.handshaker.close(ctx.channel(), (CloseWebSocketFrame) frame.retain());
final String streamName = Notificator.createStreamNameFromUri(((CloseWebSocketFrame) frame).reasonText());
if (streamName.contains(RestconfImpl.DATA_SUBSCR)) {
final ListenerAdapter listener = Notificator.getListenerFor(streamName);
if (listener != null) {
listener.removeSubscriber(ctx.channel());
LOG.debug("Subscriber successfully registered.");
Notificator.removeListenerIfNoSubscriberExists(listener);
}
} else if (streamName.contains(RestconfImpl.NOTIFICATION_STREAM)) {
final List<NotificationListenerAdapter> listeners = Notificator.getNotificationListenerFor(streamName);
if (listeners != null && !listeners.isEmpty()) {
for (final NotificationListenerAdapter listener : listeners) {
listener.removeSubscriber(ctx.channel());
}
}
}
return;
} else if (frame instanceof PingWebSocketFrame) {
ctx.channel().writeAndFlush(new PongWebSocketFrame(frame.content().retain()));
return;
}
}
@Override
public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable cause) {
ctx.close();
}
/**
* Get web socket location from HTTP request.
*
* @param req HTTP request from which the location will be returned
* @return String representation of web socket location.
*/
private static String getWebSocketLocation(final HttpRequest req) {
return "ws://" + req.headers().get(HOST) + req.uri();
}
}
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