如何在 .NET 中通过 ssh 连接实现发送和接收 hl7 数据答案

【问题标题】：How to implement send and receive hl7 data in .NET in ssh connection如何在 .NET 中通过 ssh 连接实现发送和接收 hl7 数据
【发布时间】：2019-10-08 00:44:31
【问题描述】：

我正在.Net 中实现一个应用程序。我必须通过 SSH 创建一个有效的连接，但是 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。请给我一些例子！

在这个项目中，我已经在 Android 上实现了它——它运行良好。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 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();
    }

}

所以我发现 TCP 中的缓冲区大小为 0（由于超时）。在 SimpleMLLP 测试中，SendHK7Message 方法永远不会返回

【问题讨论】：

标签： c# .net ssh hl7 mllp

【解决方案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，它会在您的传入数据中查找 Start Block。它永远找不到它。考虑到垃圾，它只会丢弃您的整个消息。因此，您不会从 Listener 那里得到任何回报。

实施 MLLP 后，您的消息（您在套接字上写入的内容）应该如下所示某事：

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

请注意，<VT>、<CR> 和 <FS> 是上述消息中的占位符。

您可以参考this 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：

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thisgithub项目。

【讨论】：

【解决方案2】：

经过几天的努力，我已经解决了这个问题。主要错误在于端口转发。我建议使用 Renci 的 SSH.Net（Tamir ssh 存在算法错误）。创建 ssh 连接后，我使用它进行端口转发：

           var port = new ForwardedPortLocal(localIP, localPort, "localhost", remotePort);

在 cmd 中使用 ipconfig /all 检查您的本地 IP。或者使用 127.0.0.1 作为回环 IP。 SimpleMLLPClient 对我不起作用，所以我使用了直接 tcp 客户端查询方式。像这样：

            TcpClient ourTcpClient = new TcpClient();
            ourTcpClient.Connect(localIP, (int)localPort); 
            NetworkStream networkStream = ourTcpClient.GetStream();

            var sendMessageByteBuffer = Encoding.UTF8.GetBytes(testHl7MessageToTransmit.ToString());

            if (networkStream.CanWrite)
            {
                networkStream.Write(sendMessageByteBuffer, 0, sendMessageByteBuffer.Length);

                Console.WriteLine("Data was sent to server successfully....");
                byte[] receiveMessageByteBuffer = new byte[ourTcpClient.ReceiveBufferSize];
                var bytesReceivedFromServer = networkStream.Read(receiveMessageByteBuffer, 0, receiveMessageByteBuffer.Length);

                if (bytesReceivedFromServer > 0 && networkStream.CanRead)
                {
                    receivedMessage.Append(Encoding.UTF8.GetString(receiveMessageByteBuffer));
                }

                var message = receivedMessage.Replace("\0", string.Empty);
                Console.WriteLine("Received message from server: {0}", message);
            }

所以它给了我 0 字节的即时答案（不是由于超时）。 Amit Joshi 的帮助来了。我用 START_OF_BLOCK、CARRIAGE_RETURN 和 END_OF_BLOCK 查询了他的建议，终于开始工作了。谢谢阿米特·乔希！

附加信息：在 Android (java/Kotlin) 中，jsch 会话 setPortForwardingL 可以使用三个参数正常工作：

        val session = jsch.getSession("user", sshIP, sshPort)
        session.setPassword("")
        jsch.addIdentity(privatekey.getAbsolutePath())
        // Avoid asking for key confirmation
        val prop = Properties()
        prop.setProperty("StrictHostKeyChecking", "no")
        session.setConfig(prop)
        session.connect(5000)
        session.setPortForwardingL(localForwardPort, "localhost", remotePort)

        val useTls = false
        val context = DefaultHapiContext()
        connection = context.newClient("localhost", localForwardPort, useTls)

【讨论】：