mono/mcs/class/System.Runtime.Remoting/System.Runtime.Remoting.Channels.Http/HttpServer.cs

//==========================================================================
//  File:       HttpServer.cs
//
//  Summary:       Implements an HttpServer to be used by the HttpServerChannel class
//				 
//
//  Classes:    internal sealed HttpServer
//		internal  sealed   ReqMessageParser
//		private RequestArguments
//
//	By :
//		Ahmad    Tantawy	[email protected]
//		Ahmad	 Kadry		[email protected]
//		Hussein  Mehanna	[email protected]
//
//==========================================================================
using System;
using System.Net.Sockets;
using System.Text;
using System.Text.RegularExpressions;
using System.Collections;

using System.Runtime.Remoting.Channels;
using System.IO;
using System.Net;
using System.Runtime.Remoting.Messaging;

namespace System.Runtime.Remoting.Channels.Http
{

	class RequestArguments
	{
		public RequestArguments(Socket SOCKET, HttpServerTransportSink SNK)
		{
			socket = SOCKET;
			snk = SNK;
		}
		public Socket socket;
		public HttpServerTransportSink snk;
	}

	internal sealed class HttpServer
	{
		public int port;
		private TcpListener listener=null;
		private const int nTimeOut = 1000;
		
		public HttpServer(int port)
		{
			try
			{
				listener = new TcpListener(port);
			}
			catch(NullReferenceException)
			{
				Console.WriteLine("The port is bound to another application");
			}
		}

		
		public static void ProcessRequest(object Object)
		{
			
			if(Object as RequestArguments == null)
				return;


			Socket socket;
			HttpServerTransportSink snk;

			RequestArguments reqArg = (RequestArguments)Object;
		
			socket = reqArg.socket;
			snk = reqArg.snk;
				
			 if(!socket.Connected)
					return;

				//Step (1) Start Reciceve the header
				ArrayList  Headers = RecieveHeader(socket);
				
				
				//Step (2) Start Parse the header
				IDictionary HeaderFields = new Hashtable();
				IDictionary CustomHeaders = new Hashtable();
				if(!ParseHeader(socket,Headers,HeaderFields,CustomHeaders))
					return;
			



				//Step (3)
			    if(!CheckRequest(socket,HeaderFields,CustomHeaders))
					return;


				//Step (4) Recieve the entity body
				byte [] buffer =new byte[(int)HeaderFields["content-length"]];
				if(!RecieveEntityBody(socket,buffer))
					return ;
				
				

				//Step (5)

			    if(! SendRequestForChannel(socket,snk,HeaderFields,CustomHeaders,buffer))
					return ;

	
		}

		private static ArrayList RecieveHeader(Socket socket)
		{
			bool bLastLine = false;
			bool bEndOfLine = false;
	
			byte[] buffer = new byte[1024];
			ArrayList  Headers = new ArrayList();



			int index =0;
			while(!bLastLine)
			{ 
				//recieve line by line 
				index = 0;
				bEndOfLine = false;

				//Step (1) is it an empty line?
				socket.Receive(buffer,index,1,SocketFlags.None);
				
				if(buffer[index++]==13)
				{
					socket.Receive(buffer,index,1,SocketFlags.None);
					bLastLine=true;
					bEndOfLine = true;
				}
				
				//Step (2) recieve line bytes
				while(!bEndOfLine)
				{
					socket.Receive(buffer,index,1,SocketFlags.None);

					if(buffer[index++]==13)
					{
						bEndOfLine = true;
						socket.Receive(buffer,index,1,SocketFlags.None);
					}
					
				}

				//Step (3) convert bytes to a string
				if(bLastLine)
					continue;
                	Headers.Add( Encoding.ASCII.GetString(buffer,0,index));

				

			}//end while loop
			
			return Headers;
		}
		
		private static bool ParseHeader(Socket socket, ArrayList Headers,IDictionary HeaderFields, IDictionary CustomHeaders)
		{

			for(int i=0;i<Headers.Count;i++)
			{

				if( ReqMessageParser.ParseHeaderField((string)Headers[i],HeaderFields))
					continue;
				if(!ReqMessageParser.IsCustomHeader((string)Headers[i],CustomHeaders ) )
				{
					SendResponse(socket,400,null,null);
					return false;
				}
				
			}

			return true;
		}

		

		private static bool CheckRequest(Socket socket,IDictionary HeaderFields , IDictionary CustomHeaders)
		{
			string temp;
			
			//Check the method
			temp = HeaderFields["method"].ToString();
			if(temp!="POST")
			{
				SendResponse(socket,501,null,null);
                return false;
			}

			//Check for the content-length field
			if(HeaderFields["content-length"]==null)
			{
				SendResponse(socket,411,null,null);
				return false;
			}
			return true;
		}

		
		private static bool RecieveEntityBody(Socket socket, byte[] buffer)
		{
			

			try
			{
				//Recieved = socket.Receive(buffer,0,buffer.Length,SocketFlags.None);
				int nr = 0;
				while (nr < buffer.Length)
					nr += socket.Receive (buffer, nr, buffer.Length - nr,SocketFlags.None);
			}
			catch(SocketException e)
			{
				switch(e.ErrorCode)
				{
					case 10060 : //TimeOut
						SendResponse(socket,408,null,null);
						break;
					default :
						//<Exception>					
						break;
				}
				
				return false;
			}//end catch

			return true;
		}
	
		private static bool SendRequestForChannel(Socket socket ,HttpServerTransportSink snk ,IDictionary HeaderFields , IDictionary CustomHeaders, byte[]buffer)
		{


			TransportHeaders THeaders = new TransportHeaders();


			Stream stream = new MemoryStream(buffer);


			if(stream.Position !=0)
				stream.Seek(0,SeekOrigin.Begin);

			//These two headers are sent to the Soap Formatter
			//IF the Soap formatter on mono will need them , then uncomment them.
			//THeaders["__ConnectionId"] = Int64.Parse("1");
			//THeaders["__IPAddress"]= ((IPEndPoint)socket.RemoteEndPoint).Address;

			THeaders["__RequestUri"] =FixURI((string)HeaderFields["request-url"]);
			THeaders["Content-Type"]=HeaderFields["content-type"];
			THeaders["__RequestVerb"]=HeaderFields["method"];
			THeaders["__HttpVersion"] = HeaderFields["http-version"];
			THeaders["User-Agent"] = HeaderFields["user-agent"];
			THeaders["Host"] = HeaderFields["host"];

			foreach(DictionaryEntry DictEntry in CustomHeaders)
			{
				THeaders[DictEntry.Key.ToString()] = DictEntry.Value.ToString();
			}

			snk.ServiceRequest(socket,stream,THeaders);
			return true;
		}

		private static string FixURI(string RequestURI)
		{

			if(RequestURI.IndexOf ( '.' ) == -1)
				return RequestURI;
			else
				return RequestURI.Substring(1);
			
		}
		
		public static bool SendResponse(Socket socket, int HttpStatusCode, ITransportHeaders  headers , Stream responseStream)
		{
			byte [] headersBuffer = null;
			byte [] entityBuffer = null;

			StringBuilder ResponseStr ;		
			String Reason = GetReasonPhrase(HttpStatusCode);

			
			//Response Line 
			ResponseStr = new StringBuilder( "HTTP/1.1 " + HttpStatusCode.ToString() + " " + Reason + "\r\n" );
			if(headers!=null)
				foreach(DictionaryEntry entry in headers)
				{
					ResponseStr.Append(entry.Key.ToString()+": "+entry.Value.ToString()+"\r\n");
				}
			
			ResponseStr.Append("Server: MS .NET Remoting, MS .NET CLR 1.0.3705.0\r\n");

			if(responseStream != null)
			if(responseStream.Length!=0)
			{
				ResponseStr.Append("Content-Length: "+responseStream.Length.ToString()+"\r\n"); 
				entityBuffer  = new byte[responseStream.Length];
				responseStream.Seek(0 , SeekOrigin.Begin);
                		responseStream.Read(entityBuffer,0,entityBuffer.Length);
			}

   			ResponseStr.Append("\r\n");
		
		   	headersBuffer =   Encoding.ASCII.GetBytes(ResponseStr.ToString());

			try
			{

				//send headersBuffer
				if(socket.Send(headersBuffer,0,headersBuffer.Length,SocketFlags.None) != headersBuffer.Length)
					return false;



				if(entityBuffer != null)
					if(socket.Send(entityBuffer,0,entityBuffer.Length,SocketFlags.None) != entityBuffer.Length)
						return false;

			}
			catch (SocketException )
			{
				//<EXCEPTION>
				//may be its the client's fault so just return with false
				return false;
			}
		 
		  return true;
		}

		public static bool SendResponse(Socket socket , int HttpStatusCode ,string ReasonPhrase, ITransportHeaders headers , Stream responseStream )
		{
			
			return true;
		}

		private static string GetReasonPhrase(int HttpStatusCode)
		{
			switch (HttpStatusCode)
			{
				case 100 : return " Continue" ;
				case 101  :return "Switching Protocols";
				case 200  :return "OK";
				case 201  :return "Created";
				case 202  :return "Accepted";
				case 203   :return "Non-Authoritative Information";
				case 204  :return "No Content";
				case 205   :return "Reset Content";
				case 206   :return "Partial Content";
				case 300   :return "Multiple Choices";
				case 301   :return "Moved Permanently";
				case 302   :return  "Found";
				case 303   :return  "See Other";
				case 304   :return  "Not Modified";
				case 305  :return   "Use Proxy";
				case 307   :return  "Temporary Redirect";
				
				case 400   :return  "Bad Request";
				case 401   :return  "Unauthorized";
				case 402   :return  "Payment Required";
				case 403   :return  "Forbidden";
				case 404   :return  "Not Found";
				case 405   :return  "Method Not Allowed";
				case 406   :return  "Not Acceptable";
											 
				case 407   :return  "Proxy Authentication Required";
				case 408   :return  "Request Time-out";
				case 409   :return  "Conflict";
				case 410   :return  "Gone";
				case 411   :return  "Length Required";
				case 412   :return  "Precondition Failed";
				case 413   :return  "Request Entity Too Large";
				case 414   :return  "Request-URI Too Large";
				case 415   :return  "Unsupported Media Type";
				case 416   :return  "Requested range not satisfiable";
				case 417   :return  "Expectation Failed";
				
				case 500  :return   "Internal Server Error";
				case 501  :return   "Not Implemented";
				case 502   :return  "Bad Gateway";
				case 503  :return   "Service Unavailable";
				case 504   :return  "Gateway Time-out";
				case 505   :return  "HTTP Version not supported";
				default: return "";

			}
		}
		
	}
	
	
	 internal  sealed class   ReqMessageParser
	{
		 private  const int nCountReq = 14;
		 private  const int nCountEntity = 15;

		 private static bool bInitialized = false;

		 private static String [] ReqRegExpString = new String [nCountReq ];
		 private static String [] EntityRegExpString = new String[nCountEntity]; 
		 
		 private static Regex [] ReqRegExp = new Regex[nCountReq];
		 private static Regex [] EntityRegExp = new Regex[nCountEntity];
		 

		 
		 public  ReqMessageParser()
		{
			

		}

		 public static bool  ParseHeaderField(string buffer,IDictionary headers)
		 {
			
			 try
			 {

				 if(!bInitialized)
				 {
					 Initialize();
					 bInitialized =true;
				 }
			 

				 if(IsRequestField(buffer,headers))
					 return true;
				 if(IsEntityField(buffer,headers))
					 return true ;
			 
			 }
			 catch(Exception )
			 {
				 //<Exception>

			 }

			 //Exception

			 return false;

		 }
		  

		 
		 private static bool Initialize()
		 {
			 if(bInitialized)
				 return true;

			 bInitialized = true;

			 //initialize array
			 //Create all the Regular expressions
			 InitializeRequestRegExp();
			 InitiazeEntityRegExp();

			 for(int i=0;i<nCountReq;i++)
				 ReqRegExp[i] = new Regex(ReqRegExpString[i],RegexOptions.Compiled|RegexOptions.IgnoreCase);
			
			 for(int i=0;i<nCountEntity;i++)
				 EntityRegExp[i] = new Regex(EntityRegExpString[i],RegexOptions.Compiled|RegexOptions.IgnoreCase);

			 return true;

		 }

		 private static void InitializeRequestRegExp()
		 {
			 //Request Header Fields
			 //
			 ReqRegExpString[0] = "^accept(\\s*:\\s*)(?<accept>\\S+)(\\s*|)(\\s*)$";
			 ReqRegExpString[1] = "^accept-charset(\\s*:\\s*)(?<accept_charset>\\S+(\\s|\\S)*\\S)(\\s*)$";
			 ReqRegExpString[2] = "^accept-encoding(\\s*:\\s*)(?<accept_Encoding>\\S+(\\s|\\S)*\\S)(\\s*)$";
			 ReqRegExpString[3] = "^authorization(\\s*:\\s*)(?<authorization>\\S+(\\s|\\S)*\\S)(\\s*)$";
			 ReqRegExpString[4] = "^accept-language(\\s*:\\s*)(?<accept_Language>\\S+(\\s|\\S)*\\S)(\\s*)$";
			 ReqRegExpString[5] = "^from(\\s*:\\s*)(?<from>\\S+(\\s|\\S)*\\S)(\\s*)$";
			 ReqRegExpString[6] = "^host(\\s*:\\s*)(?<host>\\S+(\\s|\\S)*\\S)(\\s*)$";
			 ReqRegExpString[7] = "^if-modified-since(\\s*:\\s*)(?<if_modified>\\S+(\\s|\\S)*\\S)(\\s*)$";
			 ReqRegExpString[8] = "^proxy-authorization(\\s*:\\s*)(?<proxy_auth>\\S+(\\s|\\S)*\\S)(\\s*)$";
			 ReqRegExpString[9] = "^range(\\s*:\\s*)(?<range>\\S+(\\s|\\S)*\\S)(\\s*)$";
			 ReqRegExpString[10] = "^user-agent(\\s*:\\s*)(?<user_agent>\\S+(\\s|\\S)*\\S)(\\s*)$";
			 ReqRegExpString[11] = "^expect(\\s*:\\s*)(?<expect>\\S+(\\s|\\S)*\\S)(\\s*)$";
			 ReqRegExpString[12] = "^connection(\\s*:\\s*)(?<connection>\\S+(\\s|\\S)*\\S)(\\s*)$";
			 ReqRegExpString[13] = "^(?<method>\\w+)(\\s+)(?<request_url>\\S+)(\\s+)(?<http_version>\\S+)(\\s*)$";
			// ReqRegExpString[14] = "";			 
		 }

		 private static void InitiazeEntityRegExp()
		 {
			EntityRegExpString[0] = "^allow(\\s*:\\s*)(?<allow>[0-9]+)(\\s*)$";
		    EntityRegExpString[1] = "^content-encoding(\\s*:\\s*)(?<content_encoding>\\S+(\\s|\\S)*\\S)(\\s*)$";
			EntityRegExpString[2] = "^content-language(\\s*:\\s*)(?<content_language>\\S+(\\s|\\S)*\\S)(\\s*)$";
			EntityRegExpString[3] = "^content-length(\\s*:\\s*)(?<content_length>[0-9]+)(\\s*)$";
			EntityRegExpString[4] = "^content-range(\\s*:\\s*)(?<content_range>\\S+(\\s|\\S)*\\S)(\\s*)$";
			EntityRegExpString[5] = "^content-type(\\s*:\\s*)(?<content_type>\\S+(\\s|\\S)*\\S)(\\s*)$";
			EntityRegExpString[6] = "^content-version(\\s*:\\s*)(?<content_version>\\S+(\\s|\\S)*\\S)(\\s*)$";
			EntityRegExpString[7] = "^derived-from(\\s*:\\s*)(?<derived_from>\\S+(\\s|\\S)*\\S)(\\s*)$";
			EntityRegExpString[8] = "^expires(\\s*:\\s*)(?<expires>\\S+(\\s|\\S)*\\S)(\\s*)$";//date
			EntityRegExpString[9] = "^last-modified(\\s*:\\s*)(?<last_modified>\\S+(\\s|\\S)*\\S)(\\s*)$";//date
			EntityRegExpString[10] = "^link(\\s*:\\s*)(?<link>\\S+(\\s|\\S)*\\S)(\\s*)$";
			EntityRegExpString[11] = "^title(\\s*:\\s*)(?<title>\\S+(\\s|\\S)*\\S)(\\s*)$";
		    EntityRegExpString[12] = "^transfere-encoding(\\s*:\\s*)(?<transfere_encoding>\\S+(\\s|\\S)*\\S)(\\s*)$";
		    EntityRegExpString[13] = "^url-header(\\s*:\\s*)(?<url_header>\\S+(\\s|\\S)*\\S)(\\s*)$";
			EntityRegExpString[14] = "^extension-header(\\s*:\\s*)(?<extension_header>\\S+(\\s|\\S)*\\S)(\\s*)$";
		 }
				
		 private static void CopyGroupNames(Regex regEx , Match m , IDictionary headers)
		 {
			 
			 if(!m.Success)
				 return;

			 string [] ar = regEx.GetGroupNames();
			 GroupCollection gc = m.Groups;

			 for(int i=0;i<ar.Length;i++)
			 {
				 if(! char.IsLetter(ar[i],0))
					 continue;
                 
				headers.Add(ar[i],gc[ar[i]].Value);
			 }
		 }
		 

		 private static bool IsRequestField(string buffer , IDictionary HeaderItems)
		 {
			 
			 if(Request_accept(buffer , HeaderItems))
				 return true;

			 if(Request_accept_charset(buffer , HeaderItems))
				 return true;

			 if(Request_accept_encoding(buffer , HeaderItems))
				 return true;

			 if(Request_accept_language(buffer , HeaderItems))
				 return true;

			 if(Request_authorization(buffer , HeaderItems))
				 return true;

			 if(Request_connection(buffer , HeaderItems))
				 return true;

			 if(Request_expect(buffer , HeaderItems))
				 return true;

			 if(Request_from(buffer , HeaderItems))
				 return true;

			 if(Request_host(buffer , HeaderItems))
				 return true;

			 if(Request_modified(buffer , HeaderItems))
				 return true;

			 if(Request_proxy_authorization(buffer , HeaderItems))
				 return true;

			 if(Request_user_agent(buffer , HeaderItems))
				 return true;

			 if(Request_request_line(buffer , HeaderItems))
				 return true;

			 return false;
		 }

		 private static bool IsEntityField(string buffer , IDictionary HeaderItems)
		 {
			 if(Entity_allow(buffer , HeaderItems))
				 return true;

			 if(Entity_content_encoding(buffer , HeaderItems))
				 return true;

			 if(Entity_content_language(buffer , HeaderItems))
				 return true;

			 if(Entity_content_length(buffer , HeaderItems))
				 return true;

			 if(Entity_content_range(buffer , HeaderItems))
				 return true;

			 if(Entity_content_type(buffer , HeaderItems))
				 return true;

			 if(Entity_content_version(buffer , HeaderItems))
				 return true;

			 if(Entity_dervied_from(buffer , HeaderItems))
				 return true;

			 if(Entity_expires(buffer , HeaderItems))
				 return true;

			 if(Entity_extension_header(buffer , HeaderItems))
				 return true;

			 if(Entity_last_modified(buffer , HeaderItems))
				 return true;

			 if(Entity_link(buffer , HeaderItems))
				 return true;

			 if(Entity_title(buffer , HeaderItems))
				 return true;

			 if(Entity_transfere_encoding(buffer , HeaderItems))
				 return true;
			 
			 if(Entity_url_header(buffer , HeaderItems))           
				 return true;

			 return false;

		 }
		
		 public static bool IsCustomHeader(string buffer,IDictionary CustomHeader)
		 {
			 Regex CustomHeaderEx = new Regex("^(?<header>\\S+)(\\s*:\\s*)(?<field>\\S+(\\s|\\S)*\\S)(\\s*)",RegexOptions.Compiled);
			
			 Match m = CustomHeaderEx.Match(buffer);
			 if(!m.Success)
				 return false;

			 CustomHeader.Add(m.Groups["header"].Value,m.Groups["field"].Value);
			 return true;

		 }
		
		 //********************************************************
		 //REQUEST
		 private static bool Request_accept(string buffer,IDictionary HeaderItems)
		 {
			 Match m = ReqRegExp[0].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("accept",m.Groups["accept"].Value);
			 return true;
		 }

		 private static bool Request_accept_charset(string buffer,IDictionary HeaderItems)
		 {
			 Match m = ReqRegExp[1].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("accept-charset",m.Groups["accept_charset"].Value);
			 return true;

		 }
		 private static bool Request_accept_encoding(string buffer,IDictionary HeaderItems)
		 {
			 Match m = ReqRegExp[2].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("accept-encoding",m.Groups["accept_encoding"].Value);
			 return true;
		 }
		 private static bool Request_authorization(string buffer,IDictionary HeaderItems)
		 {
			 Match m = ReqRegExp[3].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("authorization",m.Groups["authorization"].Value);
			 return true;
		 }
		 private static bool Request_accept_language(string buffer,IDictionary HeaderItems)
		 {
			 Match m = ReqRegExp[4].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("accept-language",m.Groups["accept_language"].Value);
			 return true;
		 }
		 private static bool Request_from(string buffer,IDictionary HeaderItems)
		 {
			 Match m = ReqRegExp[5].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("from",m.Groups["from"].Value);
			 return true;
		 }
		 private static bool Request_host(string buffer,IDictionary HeaderItems)
		 {
			 Match m = ReqRegExp[6].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("host",m.Groups["host"].Value);
			 return true;
		 }
		 private static bool Request_modified(string buffer,IDictionary HeaderItems)
		 {
			 Match m = ReqRegExp[7].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("modified",m.Groups["modified"].Value);
			 return true;
		 }
		 private static bool Request_proxy_authorization(string buffer,IDictionary HeaderItems)
		 {
			 Match m = ReqRegExp[8].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("proxy-authorization",m.Groups["proxy_authorization"].Value);
			 return true;
		 }
		 private static bool Request_range(string buffer , IDictionary HeaderItems)
		 {
			 Match m = ReqRegExp[9].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("range",m.Groups["range"].Value);
			 return true;
			 
		 }
		 private static bool Request_user_agent(string buffer,IDictionary HeaderItems)
		 {
			 Match m = ReqRegExp[10].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("user-agent",m.Groups["user_agent"].Value);
			 return true;
		 }
		 private static bool Request_expect(string buffer,IDictionary HeaderItems)
		 {
			 Match m = ReqRegExp[11].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("expect",m.Groups["expect"].Value);
			 return true;
		 }

		 private static bool Request_connection(string buffer,IDictionary HeaderItems)
		 {
			 Match m = ReqRegExp[12].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("connection",m.Groups["connection"].Value);
			 return true;
		 }

		 private static bool Request_request_line(string buffer, IDictionary HeaderItems)
		 {
			 Match m = ReqRegExp[13].Match(buffer);
			 if(!m.Success)
				 return false;
			//ReqRegExpString[13] = "(?<method>\\w+)(\\s+)(?<request_url>\\S+)(\\s+)(?<http_version>\\S+)";
			 
			 HeaderItems.Add("method",m.Groups["method"].Value);
			 HeaderItems.Add("request-url",m.Groups["request_url"].Value);
			 HeaderItems.Add("http-version",m.Groups["http_version"].Value);
			 return true;
		 }
		//********************************************************

		
		 //********************************************************
		 //ENTITY
		 private static bool Entity_allow(string buffer,IDictionary HeaderItems)
		 {
			 Match m = EntityRegExp[0].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("allow",m.Groups["allow"].Value);
			 return true;
		 }

		 
		 private static bool Entity_content_encoding(string buffer,IDictionary HeaderItems)
		 {
			 Match m = EntityRegExp[1].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("content-encoding",m.Groups["content_encoding"].Value);
			 return true;
		 }
		 private static bool Entity_content_language(string buffer,IDictionary HeaderItems)
		 {
			 Match m = EntityRegExp[2].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("content-language",m.Groups["content_language"].Value);
			 return true;
		 }
		 private static bool Entity_content_length(string buffer,IDictionary HeaderItems)
		 {
			 Match m = EntityRegExp[3].Match(buffer);
			 if(!m.Success)
				 return false;
			
			int length;
			 try
			 {
				 length = Int32.Parse(m.Groups["content_length"].ToString());
			 }
			 catch (Exception )
			 {
				 //<Exception>
				 return false;
			 }

			 HeaderItems.Add("content-length",length);
			 return true;
		 }
		 private static bool Entity_content_range(string buffer,IDictionary HeaderItems)
		 {
			 Match m = EntityRegExp[4].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("content-range",m.Groups["content_range"].Value);
			 return true;
		 }
		 private static bool Entity_content_type(string buffer,IDictionary HeaderItems)
		 {
			 Match m = EntityRegExp[5].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("content-type",m.Groups["content_type"].Value);
			 return true;
		 }

		 private static bool Entity_content_version(string buffer,IDictionary HeaderItems)
		 {
			 Match m = EntityRegExp[6].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("content-version",m.Groups["content_version"].Value);
			 return true;
		 }
		 private static bool Entity_dervied_from(string buffer,IDictionary HeaderItems)
		 {
			 Match m = EntityRegExp[7].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("dervied-from",m.Groups["dervied_from"].Value);
			 return true;
		 }
		 private static bool Entity_expires(string buffer,IDictionary HeaderItems)
		 {
			 Match m = EntityRegExp[8].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("expires",m.Groups["expires"].Value);
			 return true;
		 }
		 private static bool Entity_last_modified(string buffer,IDictionary HeaderItems)
		 {
			 Match m = EntityRegExp[9].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("last-modified",m.Groups["last_modified"].Value);
			 return true;
		 }
		 private static bool Entity_link(string buffer,IDictionary HeaderItems)
		 {
			 Match m = EntityRegExp[10].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("link",m.Groups["link"].Value);
			 return true;
		 }
		 private static bool Entity_title(string buffer,IDictionary HeaderItems)
		 {
			 Match m = EntityRegExp[11].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("title",m.Groups["title"].Value);
			 return true;
		 }

		 private static bool Entity_transfere_encoding(string buffer,IDictionary HeaderItems)
		 {
			 Match m = EntityRegExp[12].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("transfere-encoding",m.Groups["transfere_encoding"].Value);
			 return true;
		 }
		 private static bool Entity_url_header(string buffer,IDictionary HeaderItems)
		 {
			 Match m = EntityRegExp[13].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("url-header",m.Groups["url_header"].Value);
			 return true;
		 }

		 private static bool Entity_extension_header(string buffer,IDictionary HeaderItems)
		 {
			 Match m = EntityRegExp[14].Match(buffer);
			 if(!m.Success)
				 return false;
			
			 HeaderItems.Add("extension-header",m.Groups["extension_header"].Value);
			 return true;
		 }

		 //********************************************************		 
	}

}