README.md

LibNetty RESP Project

Provides codec components for RESP(REdis Serialization Protocol).

Quick Start

Client Side

RespMessageEncoder respMessageEncoder = new RespMessageEncoder();
EventLoopGroup group = new NioEventLoopGroup();
Bootstrap b = new Bootstrap().group(group).channel(NioSocketChannel.class)
    .option(ChannelOption.TCP_NODELAY, true)
    .handler(new ChannelInitializer<Channel>() {
        @Override
        protected void initChannel(Channel ch) throws Exception {
            ch.pipeline().addLast(respMessageEncoder)
                .addLast(new DefaultRespMessageDecoder())
                .addLast(new TestClientHandler());
        }
    });
ChannelFuture future = b.connect("127.0.0.1", 6379).sync();
if (future.isSuccess()) {
    Channel channel = future.channel();
    DefaultArrayMessage cmd = DefaultArrayMessage.bulkStringArrayAscii(channel.alloc(), "GET", "key");
    channel.writeAndFlush(cmd);
}

TestClientHandler.java

class TestClientHandler extends SimpleChannelInboundHandler<RespMessage> {
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, RespMessage msg) throws Exception {
        // RespIntegerMessage, RespErrorMessage, RespIntegerMessage, RespBulkStringMessage, RespArrayMessage
        System.out.println(msg);
        ...
    }
}

Server Side

RespMessageEncoder respMessageEncoder = new RespMessageEncoder();
NioEventLoopGroup group = new NioEventLoopGroup();
try {
    ServerBootstrap b = new ServerBootstrap().group(group).channel(NioServerSocketChannel.class)
            .option(ChannelOption.SO_BACKLOG, 512).childOption(ChannelOption.TCP_NODELAY, true)
            .childHandler(new ChannelInitializer<Channel>() {
                @Override
                protected void initChannel(Channel ch) throws Exception {
                    ch.pipeline().addLast(respMessageEncoder)
                        .addLast(new RedisRequestDecoder())
                        .addLast(new TestServerHandler());
                }
            });
    b.bind(6379).sync();
    System.out.println("TestServer started!");
    System.in.read();
} finally {
    group.shutdownGracefully();
}

TestServerHandler.java

class TestServerHandler extends SimpleChannelInboundHandler<RedisRequest> {
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, RedisRequest msg) throws Exception {
        // message received
        System.out.println("-- message received --");
        System.out.println(msg);
        String commond = msg.command().toText().toUpperCase();
        switch (commond) {
        case "ECHO":
            // always returns message
            ctx.writeAndFlush((msg.argument(1).retainedDuplicate());
            break;
        case "QUIT":
            ctx.writeAndFlush(RespMessages.ok()).addListener(CLOSE);
            break;
        case "PING":
            ctx.writeAndFlush(RespMessages.pong());
            break;
        case "SELECT":
            // just returns OK
            ctx.writeAndFlush(RespMessages.ok());
            break;
        default:
            RespErrorMessage error = DefaultErrorMessage.createErrAscii(ctx.alloc(), "unknown command " + command);
            ctx.writeAndFlush(error).addListener(CLOSE);
            break;
        }
    }
}