Sending a multiline string over NamedPipe?

Question

How can I send a multiline string with blank lines over a NamedPipe?

If I send a string

string text= @"line 1 
line2

line four
";
StreamWriter sw = new StreamWriter(client);
sw.Write(text);

I get on the server side only "line 1":

StreamReader sr = new StreamReader(server);
string message = sr.ReadLine();

When I try something like this

StringBuilder message = new StringBuilder();
string line;
while ((line = sr.ReadLine()) != null)
{
    message.Append(line + Environment.NewLine);
}

It hangs in the loop while the client is connected and only releases when the client disconnects.

Any ideas how I can get the whole string without hanging in this loop? I need to to process the string and return it on the same way to the client.

It's important that I keep the original formatting of the string including blank lines and whitespace.

Answer 1

StreamReader is a line-oriented reader. It will read the first line (terminated by a newline). If you want the rest of the text, you have to issue multiple readlines. That is:

StreamReader sr = new StreamReader(server);
string message = sr.ReadLine(); // will get "line1"
string message2 = sr.ReadLine(); // will get "line2"

You don't want to "read to end" on a network stream, because that's going to hang the reader until the server closes the connection. That might be a very long time and could overflow a buffer.

Typically, you'll see this:

NetworkStream stream = CreateNetworkStream(); // however you're creating the stream
using (StreamReader reader = new StreamReader(stream))
{
    string line;
    while ((line = reader.ReadLine()) != null)
    {
        // process line received from stream
    }
}

That gives you each line as it's received, and will terminate when the server closes the stream.

If you want the reader to process the entire multi-line string as a single entity, you can't reliably do it with StreamReader. You'll probably want to use a BinaryWriter on the server and a BinaryReader on the client.