io.viewserver.network.netty.websocket.WebSocketServerHandler.java Source code

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Here is the source code for io.viewserver.network.netty.websocket.WebSocketServerHandler.java

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/*
 * Copyright 2016 Claymore Minds Limited and Niche Solutions (UK) Limited
 *
 * 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 io.viewserver.network.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.*;
import io.netty.handler.codec.http.websocketx.*;
import io.netty.util.CharsetUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.net.URI;

/**
 * Created by nick on 27/06/15.
 */
public class WebSocketServerHandler extends SimpleChannelInboundHandler<Object> {
    private static final Logger log = LoggerFactory.getLogger(WebSocketServerHandler.class);
    private WebSocketServerHandshaker handshaker;
    private URI uri;

    public WebSocketServerHandler(URI uri) {
        this.uri = uri;
    }

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

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

    private void handleHttpRequest(ChannelHandlerContext ctx, FullHttpRequest req) {
        if (!req.getDecoderResult().isSuccess()) {
            sendHttpResponse(ctx, req,
                    new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.BAD_REQUEST));
            return;
        }

        if (req.getMethod() != HttpMethod.GET) {
            sendHttpResponse(ctx, req,
                    new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.FORBIDDEN));
            return;
        }

        WebSocketServerHandshakerFactory handshakerFactory = new WebSocketServerHandshakerFactory(uri.toString(),
                null, true);
        handshaker = handshakerFactory.newHandshaker(req);
        if (handshaker == null) {
            WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(ctx.channel());
        } else {
            handshaker.handshake(ctx.channel(), req);
        }
    }

    private void handleWebSocketFrame(ChannelHandlerContext ctx, WebSocketFrame 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 BinaryWebSocketFrame)) {
            throw new UnsupportedOperationException(
                    String.format("%s frame types not supported", frame.getClass().getName()));
        }

        ctx.fireChannelRead(frame.content().retain());
    }

    private void sendHttpResponse(ChannelHandlerContext ctx, FullHttpRequest req, FullHttpResponse res) {
        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());
        }

        ChannelFuture channelFuture = ctx.channel().writeAndFlush(res);
        if (!HttpHeaders.isKeepAlive(req) || res.getStatus().code() != 200) {
            channelFuture.addListener(ChannelFutureListener.CLOSE);
        }
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        log.error("Error handling web socket request", cause);
        ctx.close();
    }
}