HTTPStub.cs

using System;
using System.IO;
using System.Threading;
using Common;
using System.Net;
using System.Net.Sockets;

namespace Server
{
        public class HTTPStub {
                public bool usingProxy;
                public string proxyHost;
                public int proxyPort;
                public int sendTimeoutMS;
                public int receiveTimeoutMS;

                public void Init() {
                        usingProxy = false;
                        proxyHost = "wwwcache.cam.ac.uk";
                        proxyPort = 8080;
                        sendTimeoutMS = 15 * 1000;
                        receiveTimeoutMS = 30 * 1000;
                }

                public HTTPStub() {
                        Init();
                }

                public HTTPResponseQueueObject ServiceRequest(HTTPRequest req) {
                        HTTPResponseQueueObject responseQObj = null;
                        Socket sock = null;
                        try {
                                sock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                                IPEndPoint remoteEndPoint;
                                if (usingProxy) {
                                        remoteEndPoint = new IPEndPoint(Dns.GetHostByName(proxyHost).AddressList[0], proxyPort);
                                } else {
                                        remoteEndPoint = new IPEndPoint(Dns.GetHostByName(req.Hostname).AddressList[0], req.Port);
                                }
                                sock.Connect(remoteEndPoint);
                                sock.Blocking = true;
                                sock.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReceiveTimeout, receiveTimeoutMS);
                                sock.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.SendTimeout, sendTimeoutMS);
                                byte[] outputBuffer = req.ToHTTPByteArray();
                                int bytesSent = sock.Send(outputBuffer);
                                if (bytesSent != outputBuffer.Length) {
                                        throw new ApplicationException("Byte send mismatch");
                                }
                                //sock.Shutdown(SocketShutdown.Send);

                                // build up the response
                                byte[] buffer = new byte[8 * 1024];                             
                                MemoryStream ms = new MemoryStream();
                                int bytesRead = sock.Receive(buffer, buffer.Length, SocketFlags.None);  
                                while (bytesRead != 0) {
                                        ms.Write(buffer, 0, bytesRead);
                                        bytesRead = sock.Receive(buffer, buffer.Length, SocketFlags.None);      
                                }
                                ms.Seek(0, SeekOrigin.Begin);
                                Stream str = (Stream)ms;
                                responseQObj = new HTTPResponseQueueObject(ref str);
                                str.Close();
                                sock.Shutdown(SocketShutdown.Both);
                                sock.Close();
                        } catch (Exception ex) {
                                Console.WriteLine("*** Unable to fetch response: {0} ***", ex); // if error, return browser error and message.
                                string returnheaders = "HTTP/1.0 500 Server Error\r\nContent-type: text/html\r\n\r\n";
                                responseQObj = new HTTPResponseQueueObject(new HTTPResponseHeader(returnheaders));
                                responseQObj.AppendBody(new HTTPBody(System.Text.Encoding.ASCII.GetBytes(FormatError(ex))));
                        }
                                return responseQObj;
                }

                public string FormatError(Exception ex) {
                        System.Text.StringBuilder sb = new System.Text.StringBuilder();
                        sb.Append(@"<HTML><HEAD><TITLE>GPRSWeb Error</TITLE></HEAD><BODY>");
                        sb.Append(String.Format(@"<H1>{0}</H1><P>An error occured when trying to fetch your document. The error message was <i>{1}</i>", ex.GetType().Name, ex.Message));
                        sb.Append(String.Format(@"<P>Stack Trace<P><PRE>{0}</PRE>", ex.StackTrace));
                        sb.Append(String.Format(@"<P>Full details: <p><PRE>{0}</PRE></p></body></html>", ex.ToString()));
                        return sb.ToString();
                }
        }
}

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