HttpRequestHandler.java

package com.manning.nettyinaction.chapter12;

import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandler;
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 io.netty.handler.codec.http.HttpResponseStatus;
import io.netty.handler.codec.http.HttpVersion;
import io.netty.util.CharsetUtil;

/**
 * @author <a href="mailto:norman.maurer@googlemail.com">Norman Maurer</a>
 */
@ChannelHandler.Sharable
public class HttpRequestHandler extends SimpleChannelInboundHandler<FullHttpRequest> {
    @Override
    public void channelRead0(ChannelHandlerContext ctx, FullHttpRequest request) throws Exception {
        if (HttpHeaders.is100ContinueExpected(request)) {
            send100Continue(ctx);
        }

        FullHttpResponse response = new DefaultFullHttpResponse(request.getProtocolVersion(), HttpResponseStatus.OK);
        response.content().writeBytes(getContent().getBytes(CharsetUtil.UTF_8));
        response.headers().set(HttpHeaders.Names.CONTENT_TYPE, "text/plain; charset=UTF-8");

        boolean keepAlive = HttpHeaders.isKeepAlive(request);

        if (keepAlive) {
            response.headers().set(HttpHeaders.Names.CONTENT_LENGTH, response.content().readableBytes());
            response.headers().set(HttpHeaders.Names.CONNECTION, HttpHeaders.Values.KEEP_ALIVE);
        }
        ChannelFuture future = ctx.writeAndFlush(response);

        if (!keepAlive) {
            future.addListener(ChannelFutureListener.CLOSE);
        }
    }

    protected String getContent() {
        return "This content is transmitted via HTTP\r\n";
    }

    private static void send100Continue(ChannelHandlerContext ctx) {
        FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.CONTINUE);
        ctx.writeAndFlush(response);
    }

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