如何使用 Netty 连接到运行 HTTP 服务器的 UNIX 域套接字？答案

【问题标题】：How do I connect to a UNIX domain socket running an HTTP server using Netty?如何使用 Netty 连接到运行 HTTP 服务器的 UNIX 域套接字？
【发布时间】：2020-02-15 17:26:46
【问题描述】：

我正在尝试使用 Netty 连接到 Docker UNIX 域套接字。到目前为止，这是我的尝试。

@PostConstruct
public void init() throws Exception {
    io.netty.bootstrap.Bootstrap bootstrap = new io.netty.bootstrap.Bootstrap();
    bootstrap
            .group(new NioEventLoopGroup())
            .channel(NioSocketChannel.class)
            .option(ChannelOption.SO_KEEPALIVE, true)
            .remoteAddress(new DomainSocketAddress("/var/run/docker.sock"))
            .handler(new ChannelInitializer<SocketChannel>() {
                @Override
                protected void initChannel(SocketChannel socketChannel) throws Exception {
                    socketChannel
                            .pipeline()
                            .addLast(new SimpleChannelInboundHandler<HttpObject>() {
                                @Override
                                protected void channelRead0(ChannelHandlerContext channelHandlerContext, HttpObject httpObject) throws Exception {
                                    System.out.println(httpObject);
                                }
                            });
                }
            });
    final Channel channel = bootstrap.connect().sync().channel();

    final FullHttpRequest request = new DefaultFullHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.GET, "/services", Unpooled.EMPTY_BUFFER);
    request.headers().set(HttpHeaderNames.CONNECTION, HttpHeaderValues.CLOSE);
    channel.writeAndFlush(request);
    channel.closeFuture().sync();
    System.out.println("DONE");
}

此刻我正在接受

原因：java.nio.channels.UnsupportedAddressTypeException: null

有没有关于如何使用 Netty 与 UDS 进行 HTTP 连接的示例？到目前为止，我只找到了原始 UDS 和 TCP HTTP，但没有找到组合。

【问题讨论】：

标签： docker http netty unix-socket

【解决方案1】：

这是一个有效的实现。

        io.netty.bootstrap.Bootstrap bootstrap = new io.netty.bootstrap.Bootstrap();
        final EpollEventLoopGroup epollEventLoopGroup = new EpollEventLoopGroup();
        try {
            bootstrap
                    .group(epollEventLoopGroup)
                    .channel(EpollDomainSocketChannel.class)
                    .handler(new ChannelInitializer<UnixChannel>() {
                        @Override
                        public void initChannel(UnixChannel ch) throws Exception {
                            ch
                                    .pipeline()
                                    .addLast(new HttpClientCodec())
                                    .addLast(new HttpContentDecompressor())
                                    .addLast(new SimpleChannelInboundHandler<HttpObject>() {
                                        private StringBuilder messageBuilder = new StringBuilder();
                                        @Override
                                        public void channelRead0(ChannelHandlerContext ctx, HttpObject msg) throws Exception {
                                            if (msg instanceof HttpContent) {
                                                HttpContent content = (HttpContent) msg;
                                                messageBuilder.append(content.content().toString(StandardCharsets.UTF_8));
                                                if (msg instanceof LastHttpContent) {
                                                    System.out.println(messageBuilder);
                                                }
                                            } else {
                                                System.out.println(msg.getClass());
                                            }
                                        }
                                    });
                        }
                    });
            final Channel channel = bootstrap.connect(new DomainSocketAddress("/var/run/docker.sock")).sync().channel();

            final FullHttpRequest request = new DefaultFullHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.GET, "/services", Unpooled.EMPTY_BUFFER);
            request.headers().set(HttpHeaderNames.HOST, "daemon");
            channel.writeAndFlush(request);
            channel.closeFuture().sync();
        } finally {
            epollEventLoopGroup.shutdownGracefully();
        }

注意事项：

将EpollEventLoopGroup 和EpollDomainSocketChannel 与ChannelInitializer<UnixChannel> 结合使用。
HTTP 需要管道中的 new HttpCodec() 才能使用 Netty HTTP 对象。
数据可能被分块，因此您需要将其组装并等待LastHttpContent 对象

https://github.com/trajano/netty-docker-daemon-socket

【讨论】：