如何在.NET中通过ssh连接实现发送和接收hl7数据

Question

我正在.Net 中实现一个应用程序。我必须通过 SSH 创建连接，该连接有效，但 HL7 数据接收失败。目的地是树莓派。因此，当我调试 ssh 客户端已连接时，端口已转发，tcp 客户端也已连接，但我的查询没有答案。请给我推荐一些例子！

在这个项目中，我已经在 Android 上实现了它 - 它工作得很好。所以在.Net中我尝试了NHapiTools库，我也尝试了直接的TcpClient方式。本地端口 = 远程端口。我用的是 localIP = "localhost"

static void Main(string[] args)
    {
        try
        {
            PrivateKeyFile file = new PrivateKeyFile(@"./key/private.key");
        using (var client = new SshClient(remoteIP, sshPort, username, file))
            {
                client.Connect();
                var ci = client.ConnectionInfo;
                var port = new ForwardedPortLocal(localIP, localPort, client.ConnectionInfo.Host, remotePort);
                client.AddForwardedPort(port);
                port.Start();
                var req = "MSH|^~\\&|TestAppName||AVR||20181107201939.357+0000||QRY^R02^QRY_R02|923456|P|2.5";

                ////TCP
                var tcpClient = new TcpClient();
                tcpClient.Connect(localIP, (int)localPort);
                Byte[] data = System.Text.Encoding.ASCII.GetBytes(req);

                using (var stream = tcpClient.GetStream())
                {
                    stream.Write(data, 0, data.Length);

                    using (var buffer = new MemoryStream())
                    {
                        byte[] chunk = new byte[4096];
                        int bytesRead;

                        while ((bytesRead = stream.Read(chunk, 0, chunk.Length)) > 0)
                        {
                            buffer.Write(chunk, 0, bytesRead);
                        }

                        data = buffer.ToArray();
                    }
                }
   //I used this also with same result -> no respond
   //SimpleMLLP
   /*
   var connection = new SimpleMLLPClient(localIP, localPort, 
   Encoding.UTF8);
   var response = connection.SendHL7Message(req);
   */
            }
        }

        catch (Exception ex)
        {
            Console.WriteLine(ex);
        }
        Console.ReadLine();
    }

}

所以我体验到TCP中缓冲区大小为0（由于超时）。在SimpleMLLP测试中SendHK7Message方法永远不会返回

Answer 1

您在发送消息时没有实现MLLP（也称为 LLP）协议。

Description                 HEX     ASCII   Symbol
Message starting character  0B      11      <VT>
Message ending characters   1C,0D   28,13   <FS>,<CR>

这样，当您向侦听器（TCP/MLLP 服务器）发送消息时，它会在传入数据中查找起始块。它永远找不到它。它只是将您的整个消息视为垃圾而丢弃。因此，您从 Listener 得不到任何回报。

实现 MLLP 后，您的消息（您在套接字上编写的内容）应如下所示：

<VT>MSH|^~\\&|TestAppName||AVR||20181107201939.357+0000||QRY^R02^QRY_R02|923456|P|2.5<FS><CR>

请注意上面消息中的<VT>、<CR>和<FS>是占位符。

您可以参考这篇文章了解详细信息（阅读第 4 步及以后）：

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
namespace SimpleMllpHl7ClientAdvanced
{
    public class Program
    {
        private static char END_OF_BLOCK = '\u001c';
        private static char START_OF_BLOCK = '\u000b';
        private static char CARRIAGE_RETURN = (char)13;
        static void Main(string[] args)
        {
            TcpClient ourTcpClient = null;
            NetworkStream networkStream = null;
            var testHl7MessageToTransmit = new StringBuilder();
            //a HL7 test message that is enveloped with MLLP as described in my article
            testHl7MessageToTransmit.Append(START_OF_BLOCK)
                .Append("MSH|^~\\&|AcmeHIS|StJohn|CATH|StJohn|20061019172719||ORM^O01|MSGID12349876|P|2.3")
                .Append(CARRIAGE_RETURN)
                .Append("PID|||20301||Durden^Tyler^^^Mr.||19700312|M|||88 Punchward Dr.^^Los Angeles^CA^11221^USA|||||||")
                .Append(CARRIAGE_RETURN)
                .Append("PV1||O|OP^^||||4652^Paulson^Robert|||OP|||||||||9|||||||||||||||||||||||||20061019172717|20061019172718")
                .Append(CARRIAGE_RETURN)
                .Append("ORC|NW|20061019172719")
                .Append(CARRIAGE_RETURN)
                .Append("OBR|1|20061019172719||76770^Ultrasound: retroperitoneal^C4|||12349876")
                .Append(CARRIAGE_RETURN)
                .Append(END_OF_BLOCK)
                .Append(CARRIAGE_RETURN);
            try
            {
                //initiate a TCP client connection to local loopback address at port 1080
                ourTcpClient = new TcpClient();
                ourTcpClient.Connect(new IPEndPoint(IPAddress.Loopback, 1080));
                Console.WriteLine("Connected to server....");
                //get the IO stream on this connection to write to
                networkStream = ourTcpClient.GetStream();
                //use UTF-8 and either 8-bit encoding due to MLLP-related recommendations
                var sendMessageByteBuffer = Encoding.UTF8.GetBytes(testHl7MessageToTransmit.ToString());
                if (networkStream.CanWrite)
                {
                    //send a message through this connection using the IO stream
                    networkStream.Write(sendMessageByteBuffer, 0, sendMessageByteBuffer.Length);
                    Console.WriteLine("Data was sent data to server successfully....");
                    var receiveMessageByteBuffer = Encoding.UTF8.GetBytes(testHl7MessageToTransmit.ToString());
                    var bytesReceivedFromServer = networkStream.Read(receiveMessageByteBuffer, 0, receiveMessageByteBuffer.Length);
                    // Our server for this example has been designed to echo back the message
                    // keep reading from this stream until the message is echoed back
                    while (bytesReceivedFromServer > 0)
                    {
                        if (networkStream.CanRead)
                        {
                            bytesReceivedFromServer = networkStream.Read(receiveMessageByteBuffer, 0, receiveMessageByteBuffer.Length);
                            if (bytesReceivedFromServer == 0)
                            {
                                break;
                            }
                        }                            
                    }
                    var receivedMessage = Encoding.UTF8.GetString(receiveMessageByteBuffer);
                    Console.WriteLine("Received message from server: {0}", receivedMessage);
                }
                Console.WriteLine("Press any key to exit...");
                Console.ReadLine();
            }
            catch (Exception ex)
            {
                //display any exceptions that occur to console
                Console.WriteLine(ex.Message);
            }
            finally
            {
                //close the IO strem and the TCP connection
                networkStream?.Close();
                ourTcpClient?.Close();
            }
        }
    }
}

您应该修改以下代码行，如下所示：

var req = START_OF_BLOCK + "MSH|^~\\&|TestAppName||AVR||20181107201939.357+0000||QRY^R02^QRY_R02|923456|P|2.5" + END_OF_BLOCK + CARRIAGE_RETURN;

更多开源代码可以参考这个github项目。