如何使用node.js构架用于通过TCP发送的消息? [英] How do I frame messages for sending over TCP with node.js?

问题描述

我需要从node.js TCP服务器向多个TCP客户端发送JSON字符串.

I need to send a JSON string to a number of TCP clients from a node.js TCP server.

为了从客户端的套接字/流中读取消息，我需要执行某种消息框架.一种方法是在消息的长度之前将消息的长度作为数组前缀-然后在客户端将其转换为消息的缓冲区大小.

In order to read the messages from the socket/stream on the client side I need to do some sort of message framing. One way to do this is to prefix the message with the length of the message as an array - then convert that to the buffer size for the message on the client side.

我该如何在服务器上的node.js/javascript中执行类似的操作，然后使用.NET客户端在客户端将其读出?

How would I do something like this in node.js/javascript on the server and then read it out on the client side using a .NET client?

鉴于此客户端代码，我如何使用javascript/node在服务器端正确构建消息?

Given this client side code, how would I frame the message correctly on the server side using javascript/node?

        TcpClient client = new TcpClient(server, port);
        var netStream = client.GetStream();

        // read the length of the message from the first 4 bytes
        byte[] b = new byte[4];
        netStream.Read(b, 0, b.Length);
        int messageLength = BitConverter.ToInt32(b, 0);

        // knowing the length, read the rest of the message
        byte[] buffer = new byte[messageLength];
        netStream.Read(buffer, b.Length, buffer.Length);
        var message = System.Text.Encoding.UTF8.GetString(buffer);

推荐答案

以便在Node.js中解包传入的数据，您可以尝试使用节点缓冲区 或手动创建自己的 FSM 并将其与传入的数据块一起输入

to unframe incoming data in nodejs you can try to use node-bufferlist or node-buffers or create your own FSM manually and feed it with incoming chunks of data

服务器端更简单:

function sendPacket(stream, buffer)
{
    var prefix = new Buffer(4);
    var length = buffer.length;
    var offset = 0;
    // serialize 32bit little endian unsigned int
    prefix[offset++] = length & 0xff;
    prefix[offset++] = (length >> 8)  & 0xff );
    prefix[offset++] = (length >> 16)  & 0xff );
    prefix[offset++] = (length >> 24)  & 0xff );
    stream.write(prefix);
    stream.write(buffer);
}

或者您可以使用节点v0.5 + buffer.writeUInt32

or you can use node v0.5+ buffer.writeUInt32

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