如何使用Netty处理Http Keep-Alive连接

Question

如何使用Netty处理Http Keep-Alive连接

4

我正在尝试编写一个使用HTTP Keep-Alive连接的HTTP客户端。当我从ClientBoostrap连接时，我会得到通道。我可以重复使用这个通道来发送多个HTTP请求吗？是否有示例演示HTTP Keep Alive功能？

此外，我还有另一个问题。现在我的客户端没有使用Keep-Alive连接。我在ClientHandler的messageReceived方法中调用channel.close。但似乎连接没有关闭，一段时间后套接字就会耗尽，然后我会收到BindException。如果有任何指针，将不胜感激。

谢谢。

- Supun Kamburugamuva

1个回答

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- Jonathan Schneider · Accepted Answer

只要连接标头未设置为CLOSE（可能的HttpVersion为1.1，尽管不确定）并且类似于以下代码行...

request.setHeader(HttpHeaders.Names.CONNECTION，HttpHeaders.Values.CLOSE);

...您的通道应保持打开状态以进行多个请求/响应对。

这是我今天编写的一些示例代码，用于测试。您可以在通道关闭之前向Google反弹任意数量的请求：

 public class TestHttpClient {
    static class HttpResponseReader extends SimpleChannelUpstreamHandler {
        int remainingRequests = 2;

        @Override
        public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
            HttpResponse response = (HttpResponse) e.getMessage();

            System.out.println("Beginning -------------------");
            System.out.println(new String(response.getContent().slice(0, 50).array()));
            System.out.println("End -------------------\n");

            if(remainingRequests-- > 0)
                sendRequest(ctx.getChannel());
            else
                ctx.getChannel().close();
        }
    }

    public static void main(String[] args) {
        ClientBootstrap bootstrap = new ClientBootstrap(new NioClientSocketChannelFactory());
        bootstrap.setPipeline(Channels.pipeline(
                new HttpClientCodec(),
                new HttpResponseReader()));
        // bootstrap.setOption("child.keepAlive", true); // no apparent effect

        ChannelFuture future = bootstrap.connect(new InetSocketAddress("google.com", 80));
        Channel channel = future.awaitUninterruptibly().getChannel();

        channel.getCloseFuture().addListener(new ChannelFutureListener() {
            public void operationComplete(ChannelFuture future) throws Exception {
                // this winds up getting called immediately after the receipt of the first message by HttpResponseReader!
                System.out.println("Channel closed");
            }
        });

        sendRequest(channel);

        while(true) {
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    private static void sendRequest(Channel channel) {
        // Prepare the HTTP request.
        HttpRequest request = new DefaultHttpRequest(
                HttpVersion.HTTP_1_1, HttpMethod.GET, "http://www.google.com");
        request.setHeader(HttpHeaders.Names.HOST, "google.com");
        request.setHeader(HttpHeaders.Names.ACCEPT_ENCODING, HttpHeaders.Values.GZIP);

        channel.write(request);
    }
}