opendaylight/md-sal/sal-rest-connector/src/main/java/org/opendaylight/controller/sal/streams/websockets/WebSocketServerHandler.java

   1 package org.opendaylight.controller.sal.streams.websockets;
   2
   3 import static io.netty.handler.codec.http.HttpHeaders.isKeepAlive;
   4 import static io.netty.handler.codec.http.HttpHeaders.setContentLength;
   5 import static io.netty.handler.codec.http.HttpHeaders.Names.HOST;
   6 import static io.netty.handler.codec.http.HttpMethod.GET;
   7 import static io.netty.handler.codec.http.HttpResponseStatus.BAD_REQUEST;
   8 import static io.netty.handler.codec.http.HttpResponseStatus.FORBIDDEN;
   9 import static io.netty.handler.codec.http.HttpResponseStatus.INTERNAL_SERVER_ERROR;
  10 import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;
  11 import io.netty.buffer.ByteBuf;
  12 import io.netty.buffer.Unpooled;
  13 import io.netty.channel.ChannelFuture;
  14 import io.netty.channel.ChannelFutureListener;
  15 import io.netty.channel.ChannelHandlerContext;
  16 import io.netty.channel.SimpleChannelInboundHandler;
  17 import io.netty.handler.codec.http.DefaultFullHttpResponse;
  18 import io.netty.handler.codec.http.FullHttpRequest;
  19 import io.netty.handler.codec.http.FullHttpResponse;
  20 import io.netty.handler.codec.http.HttpRequest;
  21 import io.netty.handler.codec.http.websocketx.CloseWebSocketFrame;
  22 import io.netty.handler.codec.http.websocketx.PingWebSocketFrame;
  23 import io.netty.handler.codec.http.websocketx.PongWebSocketFrame;
  24 import io.netty.handler.codec.http.websocketx.WebSocketFrame;
  25 import io.netty.handler.codec.http.websocketx.WebSocketServerHandshaker;
  26 import io.netty.handler.codec.http.websocketx.WebSocketServerHandshakerFactory;
  27 import io.netty.util.CharsetUtil;
  28
  29 import java.io.IOException;
  30
  31 import org.opendaylight.controller.sal.streams.listeners.ListenerAdapter;
  32 import org.opendaylight.controller.sal.streams.listeners.Notificator;
  33 import org.slf4j.Logger;
  34 import org.slf4j.LoggerFactory;
  35
  36 /**
  37  * {@link WebSocketServerHandler} is implementation of
  38  * {@link SimpleChannelInboundHandler} which allow handle
  39  * {@link FullHttpRequest} and {@link WebSocketFrame} messages.
  40  */
  41 public class WebSocketServerHandler extends SimpleChannelInboundHandler<Object> {
  42
  43     private static final Logger logger = LoggerFactory
  44             .getLogger(WebSocketServerHandler.class);
  45
  46     private WebSocketServerHandshaker handshaker;
  47
  48     @Override
  49     protected void channelRead0(ChannelHandlerContext ctx, Object msg)
  50             throws Exception {
  51         if (msg instanceof FullHttpRequest) {
  52             handleHttpRequest(ctx, (FullHttpRequest) msg);
  53         } else if (msg instanceof WebSocketFrame) {
  54             handleWebSocketFrame(ctx, (WebSocketFrame) msg);
  55         }
  56     }
  57
  58     /**
  59      * Checks if HTTP request method is GET and if is possible to decode HTTP
  60      * result of request.
  61      *
  62      * @param ctx
  63      *            ChannelHandlerContext
  64      * @param req
  65      *            FullHttpRequest
  66      */
  67     private void handleHttpRequest(ChannelHandlerContext ctx,
  68             FullHttpRequest req) throws Exception {
  69         // Handle a bad request.
  70         if (!req.getDecoderResult().isSuccess()) {
  71             sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1,
  72                     BAD_REQUEST));
  73             return;
  74         }
  75
  76         // Allow only GET methods.
  77         if (req.getMethod() != GET) {
  78             sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1,
  79                     FORBIDDEN));
  80             return;
  81         }
  82
  83         String streamName = Notificator.createStreamNameFromUri(req.getUri());
  84         ListenerAdapter listener = Notificator.getListenerFor(streamName);
  85         if (listener != null) {
  86             listener.addSubscriber(ctx.channel());
  87             logger.debug("Subscriber successfully registered.");
  88         } else {
  89             logger.error("Listener for stream with name '{}' was not found.",
  90                     streamName);
  91             sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1,
  92                     INTERNAL_SERVER_ERROR));
  93         }
  94
  95         // Handshake
  96         WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory(
  97                 getWebSocketLocation(req), null, false);
  98         handshaker = wsFactory.newHandshaker(req);
  99         if (handshaker == null) {
 100             WebSocketServerHandshakerFactory
 101                     .sendUnsupportedWebSocketVersionResponse(ctx.channel());
 102         } else {
 103             handshaker.handshake(ctx.channel(), req);
 104         }
 105
 106     }
 107
 108     /**
 109      * Checks response status, send response and close connection if necessary
 110      *
 111      * @param ctx
 112      *            ChannelHandlerContext
 113      * @param req
 114      *            HttpRequest
 115      * @param res
 116      *            FullHttpResponse
 117      */
 118     private static void sendHttpResponse(ChannelHandlerContext ctx,
 119             HttpRequest req, FullHttpResponse res) {
 120         // Generate an error page if response getStatus code is not OK (200).
 121         if (res.getStatus().code() != 200) {
 122             ByteBuf buf = Unpooled.copiedBuffer(res.getStatus().toString(),
 123                     CharsetUtil.UTF_8);
 124             res.content().writeBytes(buf);
 125             buf.release();
 126             setContentLength(res, res.content().readableBytes());
 127         }
 128
 129         // Send the response and close the connection if necessary.
 130         ChannelFuture f = ctx.channel().writeAndFlush(res);
 131         if (!isKeepAlive(req) || res.getStatus().code() != 200) {
 132             f.addListener(ChannelFutureListener.CLOSE);
 133         }
 134     }
 135
 136     /**
 137      * Handles web socket frame.
 138      *
 139      * @param ctx
 140      *            {@link ChannelHandlerContext}
 141      * @param frame
 142      *            {@link WebSocketFrame}
 143      */
 144     private void handleWebSocketFrame(ChannelHandlerContext ctx,
 145             WebSocketFrame frame) throws IOException {
 146         if (frame instanceof CloseWebSocketFrame) {
 147             handshaker.close(ctx.channel(),
 148                     (CloseWebSocketFrame) frame.retain());
 149             String streamName = Notificator
 150                     .createStreamNameFromUri(((CloseWebSocketFrame) frame)
 151                             .reasonText());
 152             ListenerAdapter listener = Notificator.getListenerFor(streamName);
 153             if (listener != null) {
 154                 listener.removeSubscriber(ctx.channel());
 155                 logger.debug("Subscriber successfully registered.");
 156             }
 157             Notificator.removeListenerIfNoSubscriberExists(listener);
 158             return;
 159         } else if (frame instanceof PingWebSocketFrame) {
 160             ctx.channel().write(
 161                     new PongWebSocketFrame(frame.content().retain()));
 162             return;
 163         }
 164     }
 165
 166     @Override
 167     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
 168             throws Exception {
 169         if (cause instanceof java.nio.channels.ClosedChannelException == false) {
 170             // cause.printStackTrace();
 171         }
 172         ctx.close();
 173     }
 174
 175     /**
 176      * Get web socket location from HTTP request.
 177      *
 178      * @param req
 179      *            HTTP request from which the location will be returned
 180      * @return String representation of web socket location.
 181      */
 182     private static String getWebSocketLocation(HttpRequest req) {
 183         return "http://" + req.headers().get(HOST) + req.getUri();
 184     }
 185
 186 }