serverhttp.cs
----------------------------
using System;
using System.Collections;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Threading;

class HttpProcessor {

private Socket s;
private BufferedStream bs;
private StreamReader sr;
private StreamWriter sw;
private String method;
private String url;
private String protocol;
private Hashtable hashTable;

public HttpProcessor(Socket s) {
this.s = s;
hashTable = new Hashtable();
}

public void process() {
NetworkStream ns = new NetworkStream(s, FileAccess.ReadWrite);
bs = new BufferedStream(ns);
sr = new StreamReader(bs);
sw = new StreamWriter(bs);
parseRequest();
readHeaders();
writeURL();
s.Shutdown(SocketShutdown.SdBoth);
ns.Close();
}

public void parseRequest() {
String request = sr.ReadLine();
string[] tokens = request.Split(new char[]{' '});
method = tokens[0];
url = tokens[1];
protocol = tokens[2];
}

public void readHeaders() {
String line;
while((line = sr.ReadLine()) != null && line != "") {
string[] tokens = line.Split(new char[]{':'});
String name = tokens[0];
String value = "";
for(int i = 1; i < tokens.Length; i++) {
value += tokens[i];
if(i < tokens.Length - 1) tokens[i] += ":";
}
hashTable[name] = value;
}
}

public void writeURL() {
try {
FileStream fs = new FileStream(url.Substring(1), FileMode.Open, FileAccess.Read);
writeSuccess();
BufferedStream bs2 = new BufferedStream(fs);
byte[] bytes = new byte[4096];
int read;
while((read = bs2.Read(bytes, 0, bytes.Length)) != 0) {
bs.Write(bytes, 0, read);
}
bs2.Close();
} catch(FileNotFoundException) {
writeFailure();
sw.WriteLine("File not found: " + url);
}
sw.Flush();
}

public void writeSuccess() {
sw.WriteLine("HTTP/1.0 200 OK");
sw.WriteLine("Connection: close");
sw.WriteLine();
}

public void writeFailure() {
sw.WriteLine("HTTP/1.0 404 File not found");
sw.WriteLine("Connection: close");
sw.WriteLine();
}
}

public class HttpServer {

// ============================================================
// Data

protected int port;

// ============================================================
// Constructor

public HttpServer() : this(80) {
}

public HttpServer(int port) {
this.port = port;
}

// ============================================================
// Listener

public void listen() {
Socket listener = new Socket(0, SocketType.SockStream, ProtocolType.ProtTCP);
IPAddress ipaddress = new IPAddress("127.0.0.1");
IPEndPoint endpoint = new IPEndPoint(ipaddress, port);
listener.Bind(endpoint);
listener.Blocking = true;
listener.Listen(-1);
while(true) {
Socket s = listener.Accept();
HttpProcessor processor = new HttpProcessor(s);
Thread thread = new Thread(new ThreadStart(processor.process));
thread.Start();
}
}

// ============================================================
// Main

public static int Main(String[] args) {
HttpServer httpServer;
if(args.GetLength(0) > 0) {
httpServer = new HttpServer(args[0].ToUInt16());
} else {
httpServer = new HttpServer();
}
Thread thread = new Thread(new ThreadStart(httpServer.listen));
thread.Start();
return 0;
}
}