How do I make http requests to a tcp server?

Question

I am wanting to make a TCP server that listens on port 443 so that it can receive HTTP requests and post back.

Right now I am using Apache & PHP to do this in the normal way, but is it possible to do this without a web server?

For instance I've built out a traditional TCP/IP client/server application in C# .NET. Is it possible to use this implementation to handle the HTTP requests instead of using a web server?

Answer 1

This project may help you to create a web server from scratch: MiniHttpd: an HTTP web server library using pure TCP/IP

But instead of dealing with many unnecessary details such as parsing headers, compression, authentication, ssl etc. I would use the built-in HttpListener class.

Here is a simplified(but working) multi-threaded WebServer

void CreateWebServer()
{
    HttpListener listener = new HttpListener();
    listener.Prefixes.Add("http://*:8080/");
    listener.Start();

    new Thread(
        () =>
        {
            while (true)
            {
                HttpListenerContext ctx = listener.GetContext();
                ThreadPool.QueueUserWorkItem((_) => ProcessRequest(ctx));
            }
        }
    ).Start();
}

void ProcessRequest(HttpListenerContext ctx)
{
    string responseText = "Hello";
    byte[] buf = Encoding.UTF8.GetBytes(responseText);

    Console.WriteLine(ctx.Request.Url);

    ctx.Response.ContentEncoding = Encoding.UTF8;
    ctx.Response.ContentType = "text/html";
    ctx.Response.ContentLength64 = buf.Length;


    ctx.Response.OutputStream.Write(buf, 0, buf.Length);
    ctx.Response.Close();
}

---

EDIT

I changed the server a little bit to make it host a RESTful WebService (MyService). It returns the the result as Json. You can call it as http://localhost:8080/?method=Calc&i=5&j=4 (I omitted many error checks for simplicity)

public class MyService
{
    public Result Calc(int i, int j)
    {
        return new Result() { Addition = i + j, Multiplication = i * j };
    }
}

public class Result
{
    public int Addition { set; get; }
    public int Multiplication { set; get; }
}

void CreateWebServer()
{
    MyService service = new MyService();

    HttpListener listener = new HttpListener();
    listener.Prefixes.Add("http://*:8080/");
    listener.Start();

    new Thread(
        () =>
        {
            while (true)
            {
                HttpListenerContext ctx = listener.GetContext();
                ThreadPool.QueueUserWorkItem((_) => ProcessRequest(ctx,service));
            }

        }
    ).Start();
}

void ProcessRequest(HttpListenerContext ctx,MyService service)
{
    try
    {
        string responseText = Execute(ctx, service);

        byte[] buf = Encoding.UTF8.GetBytes(responseText);

        ctx.Response.ContentEncoding = Encoding.UTF8;
        ctx.Response.ContentType = "application/json";
        ctx.Response.ContentLength64 = buf.Length;


        ctx.Response.OutputStream.Write(buf, 0, buf.Length);
    }
    catch
    {
        ctx.Response.StatusCode = (int) HttpStatusCode.NotFound;
    }

    ctx.Response.Close();
}

string Execute(HttpListenerContext ctx, MyService service)
{
    System.Collections.Specialized.NameValueCollection nv = HttpUtility.ParseQueryString(ctx.Request.Url.Query);

    MethodInfo mi = service.GetType().GetMethod(nv["method"]);
    object[] parameters =  mi.GetParameters()
                             .Select(pi => Convert.ChangeType(nv[pi.Name], pi.ParameterType))
                             .ToArray();

    return JsonConvert.SerializeObject(mi.Invoke(service, parameters));
}

Answer 2

At the lowest level, you can do this using an HTTP Listener Class.

http://geekswithblogs.net/Nitin/archive/2008/06/22/using-the-http-listener-class.aspx

I wrote something similar as a uni project once, so I can look for the code if you have any particular questions.

If you want to go higher-up you might look into web services.

Here's part of my code...see what you can do with it. :

IPAddress address = IPAddress.Parse("127.0.0.1");
        IPEndPoint port = new IPEndPoint(address, 9999); //port 9999

        TcpListener listener = new TcpListener(port);

        listener.Start();

        Console.WriteLine("--Server loaded--");

        while (true) //loop forever
        {

            Console.WriteLine("Waiting for New Client");
            Socket sock = listener.AcceptSocket();
            byte[] buffer = new byte[32];

            string incomingMessage="";

            //read:
            while (sock.Available > 0)
            {
                int gotBytes = sock.Receive(buffer);
                incomingMessage += Encoding.ASCII.GetString(buffer, 0, gotBytes);

            }

            //debugging:
            //Console.WriteLine(incomingMessage);

            //Now check whether its a GET or a POST

            if (incomingMessage.ToUpper().Contains("POST") && incomingMessage.ToUpper().Contains("/DOSEARCH")) //a search has been asked for
            {

                Console.WriteLine("Query Has Been Received");

                //extracting the post data

                string htmlPostData = incomingMessage.Substring(incomingMessage.IndexOf("songName"));

                string[] parameters = htmlPostData.Split('&');

                string[] inputs = new string[5];

                for (int i=0; i<parameters.Length; i++)
                {
                    inputs[i] = (parameters[i].Split('='))[1];
                    inputs[i] = inputs[i].Replace('+',' ');
                }

...

byte[] outbuffer = Encoding.ASCII.GetBytes(answerPage.ToString());
                sock.Send(outbuffer);

                Console.WriteLine("Results Sent");

                sock.Close();