Mocking a TCP/IP connection with C#

Question

Hi,

I'm a bit of a network n00b, so please be gentle and explain things in a really, REALLY dummy way (it seems to me that every time it comes to network related stuff, people start talking a totally different language). I'm a fairly experienced C# programmer, but lacks some skill when it comes to communication between machines.

The scenario is this: I'm working with a product that communicates with other devices through tcp/ip. Is it possible to make a dummy program that acts like ta tcp/ip connection (locally on my machine), so I can hook up my other program to it by setting its IP address (and port), and then have it return whatever mocking/testing data I want?

Answer 1

Yes: you can setup a TCP connection to a program running on your own machine. The host name you should use is localhost, or the IP address is 127.0.0.1: see also Loopback (Virtual Network Interface).

Answer 2

Yep, entirely possible. Take a look at the System.Net.Sockets.TcpClient and System.Net.Sockets.TcpListener classes - they should be a good starting point.

Answer 3

To be honest I don't see the point of 'mocking' anything here just use the proper TCP/IP connection, because obviously you can send the data over TCP/IP between 2 different applications on the same IP.

Check out this example:

http://www.codeproject.com/KB/IP/tcpclientserver.aspx

Answer 4

I have done this before. I have created a set of tools for Mocking various technologies that you can download at:

http://www.codeproject.com/KB/biztalk/Excellence.aspx

This allows you to setup a data to be sent and received. You might have to tweak it a bit but main stuff is already there.

I believe you are interested in TcpReceiveMiniServer.

Here is a mini-sample:

    static void Main(string[] args)
    {
        TcpReceiveMiniServer server = new TcpReceiveMiniServer(8789);
        server.Start();
        server.DataArrived += new TcpReceiveMiniServer.DataArrivedHandler(server_DataArrived);
        Console.Read();
    }

    static void server_DataArrived(object sender, DataArrivedEventArgs e)
    {
        // do something with e.Data
    }