ca.lambtoncollege.netty.webSocket.ServerHandlerWebSocket.java Source code

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Here is the source code for ca.lambtoncollege.netty.webSocket.ServerHandlerWebSocket.java

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package ca.lambtoncollege.netty.webSocket;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
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.HttpHeaders;
import static io.netty.handler.codec.http.HttpHeaders.Names.CONTENT_TYPE;
import static io.netty.handler.codec.http.HttpHeaders.Names.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.NOT_FOUND;
import static io.netty.handler.codec.http.HttpResponseStatus.OK;
import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;
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.TextWebSocketFrame;
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;

/**
 *
 * @author c0647015
 */
public class ServerHandlerWebSocket extends SimpleChannelInboundHandler<Object> {

    private static final String WEBSOCKET_PATH = "/websocket";

    private WebSocketServerHandshaker handshaker;

    @Override
    public void channelRead0(ChannelHandlerContext ctx, Object msg) {
        if (msg instanceof FullHttpRequest) {
            handleHttpRequest(ctx, (FullHttpRequest) msg);
        } else if (msg instanceof WebSocketFrame) {
            handleWebSocketFrame(ctx, (WebSocketFrame) msg);
        }
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) {
        ctx.flush();
    }

    private void handleHttpRequest(ChannelHandlerContext ctx, FullHttpRequest req) {
        // Handle a bad request.
        if (!req.getDecoderResult().isSuccess()) {
            sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, BAD_REQUEST));
            return;
        }

        // Allow only GET methods.
        if (req.getMethod() != GET) {
            sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, FORBIDDEN));
            return;
        }

        // Send the demo page and favicon.ico
        if ("/".equals(req.getUri())) {
            ByteBuf content = ServerIndexPageWebSocket.getContent(getWebSocketLocation(req));
            FullHttpResponse res = new DefaultFullHttpResponse(HTTP_1_1, OK, content);

            res.headers().set(CONTENT_TYPE, "text/html; charset=UTF-8");
            HttpHeaders.setContentLength(res, content.readableBytes());

            sendHttpResponse(ctx, req, res);
            return;
        }
        if ("/favicon.ico".equals(req.getUri())) {
            FullHttpResponse res = new DefaultFullHttpResponse(HTTP_1_1, NOT_FOUND);
            sendHttpResponse(ctx, req, res);
            return;
        }

        // Handshake
        WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory(getWebSocketLocation(req),
                null, true);
        handshaker = wsFactory.newHandshaker(req);
        if (handshaker == null) {
            WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(ctx.channel());
        } else {
            handshaker.handshake(ctx.channel(), req);
        }
    }

    private void handleWebSocketFrame(ChannelHandlerContext ctx, WebSocketFrame frame) {

        // Check for closing frame
        if (frame instanceof CloseWebSocketFrame) {
            handshaker.close(ctx.channel(), (CloseWebSocketFrame) frame.retain());
            return;
        }
        if (frame instanceof PingWebSocketFrame) {
            ctx.channel().write(new PongWebSocketFrame(frame.content().retain()));
            return;
        }
        if (!(frame instanceof TextWebSocketFrame)) {
            throw new UnsupportedOperationException(
                    String.format("%s frame types not supported", frame.getClass().getName()));
        }

        // Send the uppercase string back.
        String request = ((TextWebSocketFrame) frame).text();
        System.err.printf("%s received %s%n", ctx.channel(), request);
        ctx.channel().write(new TextWebSocketFrame(request.toUpperCase()));
    }

    private static void sendHttpResponse(ChannelHandlerContext ctx, FullHttpRequest req, FullHttpResponse res) {
        // Generate an error page if response getStatus code is not OK (200).
        if (res.getStatus().code() != 200) {
            ByteBuf buf = Unpooled.copiedBuffer(res.getStatus().toString(), CharsetUtil.UTF_8);
            res.content().writeBytes(buf);
            buf.release();
            HttpHeaders.setContentLength(res, res.content().readableBytes());
        }

        // Send the response and close the connection if necessary.
        ChannelFuture f = ctx.channel().writeAndFlush(res);
        if (!HttpHeaders.isKeepAlive(req) || res.getStatus().code() != 200) {
            f.addListener(ChannelFutureListener.CLOSE);
        }
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        cause.printStackTrace();
        ctx.close();
    }

    private static String getWebSocketLocation(FullHttpRequest req) {
        String location = req.headers().get(HOST) + WEBSOCKET_PATH;
        if (ServerWebSocket.SSL) {
            return "wss://" + location;
        } else {
            return "ws://" + location;
        }
    }
}