使用netty-client建立websocket连接

背景

还是由于apitable，apitable使用socket-io进行连接，连接协议是websocket

apitable本地启动的话，websocket连接正常，但是一旦将server部署到测试环境，那么websocket就会连接失败。

基于如上的问题背景，那么我就想试试使用netty-client，测试一下连接是否正常。

之前了解到的用法都是不带path的，比如ws://127.0.0.1:8080这样直接连，但是项目里的连接地址是带path的

类似如下这样ws://127.0.0.1:8080/path

经过搜索之后并没有找到使用Netty client如何进行连接。

那么写这篇文章记录下，如何使用Netty client建立带path的连接

用法

直接上代码

public class ApiTable {
    static final String URL = System.getProperty("url", "ws://10.10.134.124:31000/notification/");
  
    public static void main(String[] args) throws Exception {
        URI uri = new URI(URL);
        String scheme = uri.getScheme() == null ? "ws" : uri.getScheme();
        final String host = uri.getHost() == null ? "127.0.0.1" : uri.getHost();
        final int port;
        if (uri.getPort() == -1) {
            if ("ws".equalsIgnoreCase(scheme)) {
                port = 80;
            } else if ("wss".equalsIgnoreCase(scheme)) {
                port = 443;
            } else {
                port = -1;
            }
        } else {
            port = uri.getPort();
        }

        if (!"ws".equalsIgnoreCase(scheme) && !"wss".equalsIgnoreCase(scheme)) {
            System.err.println("Only WS(S) is supported.");
            return;
        }

        final boolean ssl = "wss".equalsIgnoreCase(scheme);
        final SslContext sslCtx;
        if (ssl) {
            sslCtx = SslContextBuilder.forClient()
                    .trustManager(InsecureTrustManagerFactory.INSTANCE).build();
        } else {
            sslCtx = null;
        }

        EventLoopGroup group = new NioEventLoopGroup();
        try {
            // Connect with V13 (RFC 6455 aka HyBi-17). You can change it to V08 or V00.
            // If you change it to V00, ping is not supported and remember to change
            // HttpResponseDecoder to WebSocketHttpResponseDecoder in the pipeline.
            final WebSocketClientHandler handler =
                    new WebSocketClientHandler(
                            WebSocketClientHandshakerFactory
                                    .newHandshaker(uri,
                                            WebSocketVersion.V13, null, true
                                            , new DefaultHttpHeaders()));

            Bootstrap b = new Bootstrap();
            b.group(group)
                    .channel(NioSocketChannel.class)
                    .handler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel ch) {
                            ChannelPipeline p = ch.pipeline();
                            if (sslCtx != null) {
                                p.addLast(sslCtx.newHandler(ch.alloc(), host, port));
                            }
                            p.addLast(handler);
                        }
                    });

            Channel ch = b.connect(uri.getHost(), port).sync().channel();
            handler.handshakeFuture().sync();
            boolean active = ch.isActive();
            boolean open = ch.isOpen();
            System.out.println("active: " + active + ", open: " + open);

            BufferedReader console = new BufferedReader(new InputStreamReader(System.in));
            while (true) {
                String msg = console.readLine();
                if (msg == null) {
                    break;
                } else if ("bye".equals(msg.toLowerCase())) {
                    ch.writeAndFlush(new CloseWebSocketFrame());
                    ch.closeFuture().sync();
                    break;
                } else if ("ping".equals(msg.toLowerCase())) {
                    WebSocketFrame frame = new PingWebSocketFrame(Unpooled.wrappedBuffer(new byte[]{8, 1, 8, 1}));
                    ch.writeAndFlush(frame);
                } else {
                    WebSocketFrame frame = new TextWebSocketFrame(msg);
                    ch.writeAndFlush(frame);
                }
            }
        } finally {
            group.shutdownGracefully();
        }
    }
}

handler

public class WebSocketClientHandler extends SimpleChannelInboundHandler<Object> {

    private final WebSocketClientHandshaker handshaker;
    private ChannelPromise handshakeFuture;

    public WebSocketClientHandler(WebSocketClientHandshaker handshaker) {
        this.handshaker = handshaker;
    }

    public ChannelFuture handshakeFuture() {
        return handshakeFuture;
    }

    @Override
    public void handlerAdded(ChannelHandlerContext ctx) {
        handshakeFuture = ctx.newPromise();
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) {
        handshaker.handshake(ctx.channel());
        System.out.println("ctx connect: " + ctx.channel().isActive());
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) {
        System.out.println("WebSocket Client disconnected!");
    }

    @Override
    public void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
        Channel ch = ctx.channel();
        if (!handshaker.isHandshakeComplete()) {
            try {
                handshaker.finishHandshake(ch, (FullHttpResponse) msg);
                System.out.println("WebSocket Client connected!");
                handshakeFuture.setSuccess();
            } catch (WebSocketHandshakeException e) {
                System.out.println("WebSocket Client failed to connect");
                handshakeFuture.setFailure(e);
            }
            return;
        }

        if (msg instanceof FullHttpResponse) {
            FullHttpResponse response = (FullHttpResponse) msg;
            throw new IllegalStateException(
                    "Unexpected FullHttpResponse (getStatus=" + response.status() +
                            ", content=" + response.content().toString(CharsetUtil.UTF_8) + ')');
        }

        WebSocketFrame frame = (WebSocketFrame) msg;
        if (frame instanceof TextWebSocketFrame) {
            TextWebSocketFrame textFrame = (TextWebSocketFrame) frame;
            System.out.println("WebSocket Client received message: " + textFrame.text());
        } else if (frame instanceof PongWebSocketFrame) {
            System.out.println("WebSocket Client received pong");
        } else if (frame instanceof CloseWebSocketFrame) {
            System.out.println("WebSocket Client received closing");
            ch.close();
        }
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        cause.printStackTrace();
        if (!handshakeFuture.isDone()) {
            handshakeFuture.setFailure(cause);
        }
        ctx.close();
    }
}