TcpListener based Web server : Web server « Socket Network « VB.Net Tutorial

1. VB.Net Tutorial
2. Socket Network
3. Web server

'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