TIP: WinInet Wrapper Module

Thursday Sep 19th 2002 by Sam Huggill
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If you've ever wanted to perform a true POST operation from Visual Basic to a CGI script, then this module includes everything you need.

This module is called modWinInet.bas. Use the SplitAddr() function to get the address in the correct format for PostInfo.

Option Explicit

'Author:    Sam Huggill
'Email:     

Private Declare Function _
   InternetOpen Lib "wininet.dll" _
 Alias "InternetOpenA" _
  (ByVal lpszCallerName As String, _
   ByVal dwAccessType As Long, _
   ByVal lpszProxyName As String, _
   ByVal lpszProxyBypass As String, _
   ByVal dwFlags As Long) As Long

 Private Declare Function InternetConnect Lib "wininet.dll" _
   Alias "InternetConnectA" _
   (ByVal hInternetSession As Long, _
    ByVal lpszServerName As String, _
    ByVal nProxyPort As Integer, _
    ByVal lpszUsername As String, _
    ByVal lpszPassword As String, _
    ByVal dwService As Long, _
    ByVal dwFlags As Long, _
    ByVal dwContext As Long) As Long

 Private Declare Function InternetReadFile Lib "wininet.dll" _
   (ByVal hFile As Long, _
    ByVal sBuffer As String, _
    ByVal lNumBytesToRead As Long, _
    lNumberOfBytesRead As Long) As Integer

 Private Declare Function HttpOpenRequest Lib "wininet.dll" _
    Alias "HttpOpenRequestA" _
    (ByVal hInternetSession As Long, _
     ByVal lpszVerb As String, _
     ByVal lpszObjectName As String, _
     ByVal lpszVersion As String, _
     ByVal lpszReferer As String, _
     ByVal lpszAcceptTypes As Long, _
     ByVal dwFlags As Long, _
     ByVal dwContext As Long) As Long

 Private Declare Function HttpSendRequest Lib "wininet.dll" _
  Alias "HttpSendRequestA" _
  (ByVal hHttpRequest As Long, _
   ByVal sHeaders As String, _
   ByVal lHeadersLength As Long, _
   ByVal sOptional As String, _
   ByVal lOptionalLength As Long) As Boolean

 Private Declare Function InternetCloseHandle Lib "wininet.dll" _
  (ByVal hInternetHandle As Long) As Boolean

 Private Declare Function HttpAddRequestHeaders Lib "wininet.dll" _
   Alias "HttpAddRequestHeadersA" _
   (ByVal hHttpRequest As Long, _
    ByVal sHeaders As String, _
    ByVal lHeadersLength As Long, _
    ByVal lModifiers As Long) As Integer


Public Function PostInfo$(srv$, script$, postdat$)

  Dim hInternetOpen As Long
  Dim hInternetConnect As Long
  Dim hHttpOpenRequest As Long
  Dim bRet As Boolean
  
  hInternetOpen = 0
  hInternetConnect = 0
  hHttpOpenRequest = 0
  
  'Use registry access settings.
  Const INTERNET_OPEN_TYPE_PRECONFIG = 0
  hInternetOpen = InternetOpen("http generic", _
                  INTERNET_OPEN_TYPE_PRECONFIG, _
                  vbNullString, _
                  vbNullString, _
                  0)
  
  If hInternetOpen <> 0 Then
     'Type of service to access.
     Const INTERNET_SERVICE_HTTP = 3
     Const INTERNET_DEFAULT_HTTP_PORT = 80
     'Change the server to your server name
     hInternetConnect = InternetConnect(hInternetOpen, _
                        srv$, _
                        INTERNET_DEFAULT_HTTP_PORT, _
                        vbNullString, _
                        "HTTP/1.0", _
                        INTERNET_SERVICE_HTTP, _
                        0, _
                        0)
  
     If hInternetConnect <> 0 Then
      'Brings the data across the wire even if it locally cached.
       Const INTERNET_FLAG_RELOAD = &H80000000
       hHttpOpenRequest = HttpOpenRequest(hInternetConnect, _
                           "POST", _
                           script$, _
                           "HTTP/1.0", _
                           vbNullString, _
                           0, _
                           INTERNET_FLAG_RELOAD, _
                           0)
  
        If hHttpOpenRequest <> 0 Then
           Dim sHeader As String
           Const HTTP_ADDREQ_FLAG_ADD = &H20000000
           Const HTTP_ADDREQ_FLAG_REPLACE = &H80000000
  sHeader = "Content-Type: application/x-www-form-urlencoded" _
             & vbCrLf
           bRet = HttpAddRequestHeaders(hHttpOpenRequest, _
             sHeader, Len(sHeader), HTTP_ADDREQ_FLAG_REPLACE _
             Or HTTP_ADDREQ_FLAG_ADD)
  
           Dim lpszPostData As String
           Dim lPostDataLen As Long
  
           lpszPostData = postdat$
           lPostDataLen = Len(lpszPostData)
           bRet = HttpSendRequest(hHttpOpenRequest, _
                  vbNullString, _
                  0, _
                  lpszPostData, _
                  lPostDataLen)
  
           Dim bDoLoop             As Boolean
           Dim sReadBuffer         As String * 2048
           Dim lNumberOfBytesRead  As Long
           Dim sBuffer             As String
           bDoLoop = True
           While bDoLoop
            sReadBuffer = vbNullString
            bDoLoop = InternetReadFile(hHttpOpenRequest, _
               sReadBuffer, Len(sReadBuffer), lNumberOfBytesRead)
            sBuffer = sBuffer & _
                 Left(sReadBuffer, lNumberOfBytesRead)
            If Not CBool(lNumberOfBytesRead) Then bDoLoop = False
           Wend
           PostInfo = sBuffer
           bRet = InternetCloseHandle(hHttpOpenRequest)
        End If
        bRet = InternetCloseHandle(hInternetConnect)
     End If
     bRet = InternetCloseHandle(hInternetOpen)
  End I

nd Function Public Sub SplitAddr(ByVal addr$, srv$, script$) 'Inputs: The full url including http:// ' Two variables that will be changed ' 'Returns: Splits the addr$ var into the server name ' and the script path Dim i% i = InStr(addr$, "/") srv$ = Mid(addr$, i + 2, Len(addr$) - (i + 1)) i = InStr(srv$, "/") script$ = Mid(srv$, i, Len(srv$) + 1 - i) srv$ = Left$(srv$, i - 1) End Sub

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