Constant reading from StreamReader from TCP connection, C#

Question

I have working script in Swift, perfectly reading TCP connection stream non-stop. I need to make the same in C# and here i got stuck. The remote service works like this: it waits for the first command, which is "*99*1##", then it replies "*#*1##" and start forwarding another similar messages to the same stream. All i need is to record all those server answers to a file. The problem is i can't get more then one server answer. Just after first server answer, i'm not able to read from the stream anymore. Peek()/Read() methods return -1, and ReadLine returns null. And i'm sure that it's wrong as from Swift script i can see that server sends me much more then just one message. First, here is Swift code (reading stream)

    let queryString: String = "*99*1##"
    let queryData: Data = queryString.data(using: String.Encoding.utf8, allowLossyConversion: false)! as Data
    queryData.withUnsafeBytes { outputStream.write($0, maxLength: queryData.count) }
    var readChars: Int = 0
    while true {
        readChars = inputStream.read(&buffer, maxLength: buffer.count)
        if (readChars > 0) {
            let readString: String = NSString(data: NSData(bytes:buffer, length:readChars) as Data, encoding: String.Encoding.utf8.rawValue)! as String
            print("\(readString)\n")
        } else {
            print ("Server closed connection\n")
            inputStream.close()
            outputStream.close()
            break
        }
    }

Communication looks like that:

Client->*99*1##
Server->*#*1##
Server->*1*34*#6#4#02##
Server->*1*1*13#4#01##
Server->*1*0*13#4#01##
and etc...

In C# i have tried StreamReader methods like ReadLine, Read, ReadToEnd and none of them gave me more then one server answer.

string address = "192.168.0.10";
int port = 20000;
TcpClient client = new TcpClient(address, port);
StreamReader sr = new StreamReader(client.GetStream());
StreamWriter sw = new StreamWriter(client.GetStream());
string command = "*99*1##";
Console.WriteLine("Client->" + command);
sw.WriteLine(command);
sw.Flush();

string data;
while (true)
{
    data = sr.ReadToEnd();
    if (data != null) 
    {
        Console.WriteLine(Server->" + data);
    } else
    {
        break;
    }
}
Console.WriteLine("Server closed connection.");

Here communication looks totally wrong:

Client->*99*1##
Server->*#*1##
Server closed connection

Second and other server answers comes after 5 to 10 seconds later then first. Maybe there is some timeout problem on my side? Server has timeout around 30 mins and i can keep session with it through the Swift or Telnet that long.

Thank you in advance for all the ideas.

Answer 1

You should use Read() instead of ReadToEnd() because reader stream keeps alive continuously. So, try like this;

string address = "127.0.0.1";
int port = 25000;
var client = new TcpClient(address, port);
StreamReader sr = new StreamReader(client.GetStream());
StreamWriter sw = new StreamWriter(client.GetStream());
client.
string command = "*99*1##";
Console.WriteLine("Client->" + command);
sw.WriteLine(command);
sw.Flush();
char[] charArray = new char[100];
while (true)
{
    var readByteCount = sr.Read(charArray, 0, charArray.Length);
    if (readByteCount > 0)
    {
        var data = new string(charArray, 0, readByteCount);
        Console.WriteLine(data + " + data");
    }
    if (!client.Connected)
    {
        break;
    }
}
Console.WriteLine("Server closed connection.");