HelloWorldHttp1Handler.java

package chapter7.recipe1.server;

import static io.netty.handler.codec.http.HttpHeaderNames.CONNECTION;
import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_LENGTH;
import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_TYPE;
import static io.netty.handler.codec.http.HttpResponseStatus.CONTINUE;
import static io.netty.handler.codec.http.HttpResponseStatus.OK;
import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;
import io.netty.buffer.ByteBuf;
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.FullHttpResponse;
import io.netty.handler.codec.http.HttpHeaderUtil;
import io.netty.handler.codec.http.HttpHeaderValues;
import io.netty.handler.codec.http.HttpRequest;

/**
 * HTTP handler that responds with a "Hello World"
 */
public class HelloWorldHttp1Handler extends SimpleChannelInboundHandler<HttpRequest> {

    @Override
    public void messageReceived(ChannelHandlerContext ctx, HttpRequest req) throws Exception {
        if (HttpHeaderUtil.is100ContinueExpected(req)) {
            ctx.write(new DefaultFullHttpResponse(HTTP_1_1, CONTINUE));
        }
        boolean keepAlive = HttpHeaderUtil.isKeepAlive(req);

        ByteBuf content = ctx.alloc().buffer();
        content.writeBytes(HelloWorldHttp2Handler.RESPONSE_BYTES.duplicate());

        FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, OK, content);
        response.headers().set(CONTENT_TYPE, "text/plain; charset=UTF-8");
        response.headers().setInt(CONTENT_LENGTH, response.content().readableBytes());

        if (!keepAlive) {
            ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
        } else {
            response.headers().set(CONNECTION, HttpHeaderValues.KEEP_ALIVE);
            ctx.writeAndFlush(response);
        }
    }

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