Moteur HTTP

Imports System
Imports System.Text
Imports System.IO
Imports System.Net
Imports System.Net.Sockets
Imports Microsoft.VisualBasic

Module ModSocket

    Private pvStrHTTPServer As String
    Private pvStrHTTPPort As Integer
    Private pvStrHTTPRequest As String

    Private pvStrHTTPAnswer As String
    Private pvStrHTTPData As String

    Property StrHTTPServer() As String
        Get
            Return pvStrHTTPServer
        End Get
        Set(ByVal Value As String)
            pvStrHTTPServer = Value
        End Set
    End Property

    Property StrHTTPPort() As Integer
        Get
            Return pvStrHTTPPort
        End Get
        Set(ByVal Value As Integer)
            pvStrHTTPPort = Value
        End Set
    End Property

    Property StrHTTPRequest() As String
        Get
            Return pvStrHTTPRequest
        End Get
        Set(ByVal Value As String)
            pvStrHTTPRequest = Value
        End Set
    End Property

    ReadOnly Property StrHTTPData() As String
        Get
            Return pvStrHTTPData
        End Get
    End Property

    ReadOnly Property StrHTTPAnswer() As String
        Get
            Return pvStrHTTPAnswer
        End Get
    End Property

    Private Function ConnectSocket() As Socket
        Dim s As Socket = Nothing
        Dim hostEntry As IPHostEntry = Nothing

        ' Get host related information.
        hostEntry = Dns.GetHostEntry(pvStrHTTPServer)

        ' Loop through the AddressList to obtain the supported AddressFamily. This is to avoid
        ' an exception that occurs when the host host IP Address is not compatible with the address family
        ' (typical in the IPv6 case).
        Dim address As IPAddress

        For Each address In hostEntry.AddressList
            Dim endPoint As New IPEndPoint(address, pvStrHTTPPort)
            Dim tempSocket As New Socket(endPoint.AddressFamily, SocketType.Stream, ProtocolType.Tcp)

            tempSocket.Connect(endPoint)

            If tempSocket.Connected Then
                s = tempSocket
                Exit For
            End If

        Next address

        Return s
    End Function


    ' This method requests the home page content for the specified server.

    Private Function SocketSendReceive() As String
        'Set up variables and String to write to the server.
        Dim ascii As Encoding = Encoding.Default
        Dim bytesSent As [Byte]() = ascii.GetBytes(pvStrHTTPRequest)
        Dim bytesReceived(255) As [Byte]

        ' Create a socket connection with the specified server and port.
        Dim s As Socket = ConnectSocket()

        If s Is Nothing Then
            Return "Connection failed"
        End If
        ' Send request to the server.
        s.Send(bytesSent, bytesSent.Length, 0)

        ' Receive the server  home page content.
        Dim bytes As Int32

        ' Read the first 256 bytes.
        Dim page As String = ""
        ' The following will block until the page is transmitted.
        Do
            bytes = s.Receive(bytesReceived, bytesReceived.Length, 0)
            'page = page + Encoding.ASCII.GetString(bytesReceived, 0, bytes)
            page = page + Encoding.Default.GetString(bytesReceived, 0, bytes)
        Loop While bytes > 0

        Return page
    End Function

    Public Function MakeHTTPRequest(ByVal Action As Integer, ByVal Host As String, ByVal Chemin As String, ByVal Version As String, ByVal Parametres As String, ByVal Requete As String, ByVal UserAgent As String) As String
        Dim str_entete_http As String

        '----------------------------------------------------------
        If Action = 1 Then
            str_entete_http = "GET "
        ElseIf Action = 2 Then
            str_entete_http = "POST "
        Else
            MessageBox.Show("Erreur MakeHTTPRequest")
            Return vbNullString
            Exit Function
        End If

        str_entete_http = str_entete_http + "/" & Chemin

        If Action = 1 Then
            str_entete_http = str_entete_http + IIf(Parametres = vbNullString, vbNullString, "?" & Parametres)
        End If

        str_entete_http = str_entete_http + " " + Version & ControlChars.CrLf

        '----------------------------------------------------------
        str_entete_http = str_entete_http + "User-Agent: " + UserAgent & ControlChars.CrLf
        str_entete_http = str_entete_http + "Host: " & Host + ControlChars.CrLf
        '----------------------------------------------------------
        str_entete_http = str_entete_http + Requete & ControlChars.CrLf

        '----------------------------------------------------------
        If Action = 2 Then
            str_entete_http = str_entete_http + "Content-Length: " + Len(Parametres).ToString + ControlChars.CrLf + ControlChars.CrLf + Parametres
        End If

        '----------------------------------------------------------
        str_entete_http = str_entete_http + ControlChars.CrLf + ControlChars.CrLf
        Return str_entete_http
    End Function

    Public Function ExecuteHTTPRequest() As String
        Dim res As String
        Dim a As Integer

        res = SocketSendReceive()

        a = InStr(res, ControlChars.CrLf + ControlChars.CrLf)

        pvStrHTTPAnswer = Left(res, a)
        pvStrHTTPData = Right(res, Len(res) - (a + Len(ControlChars.CrLf + ControlChars.CrLf) - 1))

        Return res
    End Function

    Public Sub SetHTTPReferences(Optional ByVal server As String = "", Optional ByVal port As Integer = 0, Optional ByVal request As String = "")
        If server <> vbNullString Then pvStrHTTPServer = server
        If port <> 0 Then pvStrHTTPPort = port
        If request <> vbNullString Then pvStrHTTPRequest = request
    End Sub

End Module