VB.Net Tutorial/Socket Network/Web server

Socket based Web server

<source lang="vbnet">"Visual Basic.Net JingCai Programming 100 Examples "Author: Yong Zhang "Publisher: Water Publisher China "ISBN: 750841156 Imports System.Net Imports System.Net.Sockets Imports System.Threading Imports System.Text Imports System.IO

Public Class WebServer

 Public Shared Sub Main()
   Dim serverSocket As System.Net.Sockets.Socket
   Try
     Dim hostName As String = Dns.GetHostName()
     Dim serverIP As IPAddress = Dns.Resolve(hostName).AddressList(0)
     " Web Server Port = 80
     Dim Port As String = "80"
     Dim serverHost As New IPEndPoint(serverIP, Int32.Parse(Port))
     serverSocket = New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
     serverSocket.Bind(serverHost)
     " Backlog = 50
     serverSocket.Listen(50)
     Console.WriteLine("Web server started at: " & serverHost.Address.ToString() & ":" & Port)
     Dim httpSession As New HTTPSession(serverSocket)
     Dim serverThread As New Thread(New ThreadStart(AddressOf httpSession.ProcessThread))
     serverThread.Start()
   Catch ex As Exception
     Console.WriteLine(ex.StackTrace.ToString())
   End Try
 End Sub

End Class

Public Class HTTPSession

 Private serverSocket As System.Net.Sockets.Socket
 Private clientSocket As System.Net.Sockets.Socket

 Public Sub New(ByVal serverSocket As System.Net.Sockets.Socket)
   Me.serverSocket = serverSocket
 End Sub
 Public Sub ProcessThread()
   While (True)
     Try
       clientSocket = serverSocket.Accept()
       " Socket Information
       Dim clientInfo As IPEndPoint = CType(clientSocket.RemoteEndPoint, IPEndPoint)
       Dim serverInfo As IPEndPoint = CType(serverSocket.LocalEndPoint, IPEndPoint)
       Console.WriteLine("Client: " + clientInfo.Address.ToString() + ":" + clientInfo.Port.ToString())
       Console.WriteLine("Server: " + serverInfo.Address.ToString() + ":" + serverInfo.Port.ToString())
       " Set Thread for each Web Browser Connection
       Dim clientThread As New Thread(New ThreadStart(AddressOf ProcessRequest))
       clientThread.Start()
     Catch ex As Exception
       Console.WriteLine(ex.StackTrace.ToString())
       If clientSocket.Connected Then
         clientSocket.Close()
       End If
     End Try
   End While
 End Sub

 Protected Sub ProcessRequest()
   Dim recvBytes(1024) As Byte
   Dim htmlReq As String = Nothing
   Dim bytes As Int32
   Try
     " Receive HTTP Request from Web Browser
     bytes = clientSocket.Receive(recvBytes, 0, clientSocket.Available, SocketFlags.None)
     htmlReq = Encoding.ASCII.GetString(recvBytes, 0, bytes)
     Console.WriteLine("HTTP Request: ")
     Console.WriteLine(htmlReq)
     " Set WWW Root Path
     Dim rootPath As String = Directory.GetCurrentDirectory() & "\WWWRoot\"
     " Set default page
     Dim defaultPage As String = "index.html"
     Dim strArray() As String
     Dim strRequest As String
     strArray = htmlReq.Trim.Split(" ")
     " Determine the HTTP method (GET only)
     If strArray(0).Trim().ToUpper.Equals("GET") Then
       strRequest = strArray(1).Trim
       If (strRequest.StartsWith("/")) Then
         strRequest = strRequest.Substring(1)
       End If
       If (strRequest.EndsWith("/") Or strRequest.Equals("")) Then
         strRequest = strRequest & defaultPage
       End If
       strRequest = rootPath & strRequest
       sendHTMLResponse(strRequest)
     Else " Not HTTP GET method
       strRequest = rootPath & "Error\" & "400.html"
       sendHTMLResponse(strRequest)
     End If
   Catch ex As Exception
     Console.WriteLine(ex.StackTrace.ToString())
     If clientSocket.Connected Then
       clientSocket.Close()
     End If
   End Try
 End Sub
 " Send HTTP Response
 Private Sub sendHTMLResponse(ByVal httpRequest As String)
   Try
     " Get the file content of HTTP Request 
     Dim streamReader As StreamReader = New StreamReader(httpRequest, Encoding.Default)
     Dim strBuff As String = streamReader.ReadToEnd()
     streamReader.Close()
     streamReader = Nothing
     " The content Length of HTTP Request
     Dim respByte() As Byte = Encoding.Default.GetBytes(strBuff)
     " Set HTML Header
     Dim htmlHeader As String = _
         "HTTP/1.0 200 OK" & ControlChars.CrLf & _
         "Server: WebServer 1.0" & ControlChars.CrLf & _
         "Content-Length: " & respByte.Length & ControlChars.CrLf & _
         "Content-Type: " & getContentType(httpRequest) & _
         ControlChars.CrLf & ControlChars.CrLf
     " The content Length of HTML Header
     Dim headerByte() As Byte = Encoding.ASCII.GetBytes(htmlHeader)
     Console.WriteLine("HTML Header: " & ControlChars.CrLf & htmlHeader)
     " Send HTML Header back to Web Browser
     clientSocket.Send(headerByte, 0, headerByte.Length, SocketFlags.None)
     " Send HTML Content back to Web Browser
     clientSocket.Send(respByte, 0, respByte.Length, SocketFlags.None)
     " Close HTTP Socket connection
     clientSocket.Shutdown(SocketShutdown.Both)
     clientSocket.Close()
   Catch ex As Exception
     Console.WriteLine(ex.StackTrace.ToString())
     If clientSocket.Connected Then
       clientSocket.Close()
     End If
   End Try
 End Sub
 " Get Content Type
 Private Function getContentType(ByVal httpRequest As String) As String
   If (httpRequest.EndsWith("html")) Then
     Return "text/html"
   ElseIf (httpRequest.EndsWith("htm")) Then
     Return "text/html"
   ElseIf (httpRequest.EndsWith("txt")) Then
     Return "text/plain"
   ElseIf (httpRequest.EndsWith("gif")) Then
     Return "image/gif"
   ElseIf (httpRequest.EndsWith("jpg")) Then
     Return "image/jpeg"
   ElseIf (httpRequest.EndsWith("jpeg")) Then
     Return "image/jpeg"
   ElseIf (httpRequest.EndsWith("pdf")) Then
     Return "application/pdf"
   ElseIf (httpRequest.EndsWith("pdf")) Then
     Return "application/pdf"
   ElseIf (httpRequest.EndsWith("doc")) Then
     Return "application/msword"
   ElseIf (httpRequest.EndsWith("xls")) Then
     Return "application/vnd.ms-excel"
   ElseIf (httpRequest.EndsWith("ppt")) Then
     Return "application/vnd.ms-powerpoint"
   Else
     Return "text/plain"
   End If
 End Function

End Class</source>

TcpListener based Web server

<source lang="vbnet">"Visual Basic.Net JingCai Programming 100 Examples "Author: Yong Zhang "Publisher: Water Publisher China "ISBN: 750841156 Imports System.Net Imports System.Net.Sockets Imports System.Threading Imports System.Text Imports System.IO Public Class WebServer

 Public Shared Sub Main()
   Try
     Dim hostName As String = Dns.GetHostName()
     Dim serverIP As IPAddress = Dns.Resolve(hostName).AddressList(0)
     " Web Server Port = 80
     Dim Port As String = "80"
     Dim tcpListener As New TcpListener(serverIP, Int32.Parse(Port))
     tcpListener.Start()
     Console.WriteLine("Web server started at: " & serverIP.ToString() & ":" & Port)
     Dim httpSession As New HTTPSession(tcpListener)
     Dim serverThread As New Thread(New ThreadStart(AddressOf httpSession.ProcessThread))
     serverThread.Start()
   Catch ex As Exception
     Console.WriteLine(ex.StackTrace.ToString())
   End Try
 End Sub

End Class

Public Class HTTPSession

 Private tcpListener As System.Net.Sockets.TcpListener
 Private clientSocket As System.Net.Sockets.Socket
 Public Sub New(ByVal tcpListener As System.Net.Sockets.TcpListener)
   Me.tcpListener = tcpListener
 End Sub
 Public Sub ProcessThread()
   While (True)
     Try
       clientSocket = tcpListener.AcceptSocket()
       " Socket Information
       Dim clientInfo As IPEndPoint = CType(clientSocket.RemoteEndPoint, IPEndPoint)
       Console.WriteLine("Client: " + clientInfo.Address.ToString() + ":" + clientInfo.Port.ToString())
       " Set Thread for each Web Browser Connection
       Dim clientThread As New Thread(New ThreadStart(AddressOf ProcessRequest))
       clientThread.Start()
     Catch ex As Exception
       Console.WriteLine(ex.StackTrace.ToString())
       If clientSocket.Connected Then
         clientSocket.Close()
       End If
     End Try
   End While
 End Sub
 Protected Sub ProcessRequest()
   Dim recvBytes(1024) As Byte
   Dim htmlReq As String = Nothing
   Dim bytes As Int32
   Try
     " Receive HTTP Request from Web Browser
     bytes = clientSocket.Receive(recvBytes, 0, clientSocket.Available, SocketFlags.None)
     htmlReq = Encoding.ASCII.GetString(recvBytes, 0, bytes)
     Console.WriteLine("HTTP Request: ")
     Console.WriteLine(htmlReq)
     " Set WWW Root Path
     Dim rootPath As String = Directory.GetCurrentDirectory() & "\WWWRoot\"
     " Set default page
     Dim defaultPage As String = "index.html"
     Dim strArray() As String
     Dim strRequest As String
     strArray = htmlReq.Trim.Split(" ")
     " Determine the HTTP method (GET only)
     If strArray(0).Trim().ToUpper.Equals("GET") Then
       strRequest = strArray(1).Trim
       If (strRequest.StartsWith("/")) Then
         strRequest = strRequest.Substring(1)
       End If
       If (strRequest.EndsWith("/") Or strRequest.Equals("")) Then
         strRequest = strRequest & defaultPage
       End If
       strRequest = rootPath & strRequest
       sendHTMLResponse(strRequest)
     Else " Not HTTP GET method
       strRequest = rootPath & "Error\" & "400.html"
       sendHTMLResponse(strRequest)
     End If
   Catch ex As Exception
     Console.WriteLine(ex.StackTrace.ToString())
     If clientSocket.Connected Then
       clientSocket.Close()
     End If
   End Try
 End Sub
 " Send HTTP Response
 Private Sub sendHTMLResponse(ByVal httpRequest As String)
   Try
     " Get the file content of HTTP Request 
     Dim streamReader As StreamReader = New StreamReader(httpRequest)
     Dim strBuff As String = streamReader.ReadToEnd()
     streamReader.Close()
     streamReader = Nothing
     " The content Length of HTTP Request
     Dim respByte() As Byte = Encoding.ASCII.GetBytes(strBuff)
     " Set HTML Header
     Dim htmlHeader As String = _
         "HTTP/1.0 200 OK" & ControlChars.CrLf & _
         "Server: WebServer 1.0" & ControlChars.CrLf & _
         "Content-Length: " & respByte.Length & ControlChars.CrLf & _
         "Content-Type: " & getContentType(httpRequest) & _
         ControlChars.CrLf & ControlChars.CrLf
     " The content Length of HTML Header
     Dim headerByte() As Byte = Encoding.ASCII.GetBytes(htmlHeader)
     Console.WriteLine("HTML Header: " & ControlChars.CrLf & htmlHeader)
     " Send HTML Header back to Web Browser
     clientSocket.Send(headerByte, 0, headerByte.Length, SocketFlags.None)
     " Send HTML Content back to Web Browser
     clientSocket.Send(respByte, 0, respByte.Length, SocketFlags.None)
     " Close HTTP Socket connection
     clientSocket.Shutdown(SocketShutdown.Both)
     clientSocket.Close()
   Catch ex As Exception
     Console.WriteLine(ex.StackTrace.ToString())
     If clientSocket.Connected Then
       clientSocket.Close()
     End If
   End Try
 End Sub
 " Get Content Type
 Private Function getContentType(ByVal httpRequest As String) As String
   If (httpRequest.EndsWith("html")) Then
     Return "text/html"
   ElseIf (httpRequest.EndsWith("htm")) Then
     Return "text/html"
   ElseIf (httpRequest.EndsWith("txt")) Then
     Return "text/plain"
   ElseIf (httpRequest.EndsWith("gif")) Then
     Return "image/gif"
   ElseIf (httpRequest.EndsWith("jpg")) Then
     Return "image/jpeg"
   ElseIf (httpRequest.EndsWith("jpeg")) Then
     Return "image/jpeg"
   ElseIf (httpRequest.EndsWith("pdf")) Then
     Return "application/pdf"
   ElseIf (httpRequest.EndsWith("pdf")) Then
     Return "application/pdf"
   ElseIf (httpRequest.EndsWith("doc")) Then
     Return "application/msword"
   ElseIf (httpRequest.EndsWith("xls")) Then
     Return "application/vnd.ms-excel"
   ElseIf (httpRequest.EndsWith("ppt")) Then
     Return "application/vnd.ms-powerpoint"
   Else
     Return "text/plain"
   End If
 End Function

End Class</source>