Question

I have a function(please see code below) which reads some data from the web. The problem with this function is that sometimes it will return fast but another time it will wait indefinitely. I heard that threads helps me to wait for a definite period of time and return.

Can you please tell me how to make a thread wait for ‘x’ seconds and return if there is no activity recorded. My function also returns a string as a result, Is it possible to catch that value while using a thread?

 private string ReadMessage(SslStream sslStream)
        {
            // Read the  message sent by the server.
            // The end of the message is signaled using the
            // "<EOF>" marker.
            byte[] buffer = new byte[2048];
            StringBuilder messageData = new StringBuilder();
            int bytes = -1;

            try
            {
                bytes = sslStream.Read(buffer, 0, buffer.Length);

                // Use Decoder class to convert from bytes to UTF8
                // in case a character spans two buffers.
                Decoder decoder = Encoding.ASCII.GetDecoder();
                char[] chars = new char[decoder.GetCharCount(buffer, 0, bytes)];
                decoder.GetChars(buffer, 0, bytes, chars, 0);
                messageData.Append(chars);
                // Check for EOF.
            }
            catch (Exception ex)
            {

                throw;
            }



            return messageData.ToString();
        }

For Andre Calil’s comment:

My need is to read/write some value to a SSL server. For every write operation the server sends some response, The ReadMessage is responsible for reading the incoming message. I’ve found situations wnen the ReadMessage(sslStream.Read(buffer, 0, buffer.Length);) waits forever. To combat this problem, i considered threads which can wait for ‘x’ seconds and return after that. Following code demonstrates the working of ReadMEssage

 byte[] messsage = Encoding.UTF8.GetBytes(inputmsg);
            // Send hello message to the server. 
            sslStream.Write(messsage);
            sslStream.Flush();
            // Read message from the server.
            outputmsg = ReadMessage(sslStream);
           // Console.WriteLine("Server says: {0}", serverMessage);
            // Close the client connection.
            client.Close();

Answer 1

You can’t (sanely) make a second thread interrupt the one you’re executing this code from. Use a read timeout instead:

private string ReadMessage(SslStream sslStream)
{
    // set a timeout here or when creating the stream
    sslStream.ReadTimeout = 20*1000;
    // …
    try 
    {
        bytes = sslStream.Read(…);
    } 
    catch (IOException) 
    {
        // a timeout occurred, handle it
    }
}

As an aside, the following construct is pointless:

try
{
    // some code
}
catch (Exception ex) {
    throw;
}

If all you’re doing is rethrowing, you don’t need the try..catch block at all.