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How to upload files to a Web server by using ASP

This article was previously published under Q299692
For a Microsoft Visual Basic .NET version of this article, see 315832.
This article describes how to enable your Web server to receive file transfers from Microsoft Active Server Pages (ASP) pages by using a server-side Microsoft COM+ component.

NOTE: Microsoft Support boundaries for Visual Basic 6 development have changed. For more information, please see

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  1. Microsoft Windows 2000 with Microsoft Internet Information Server 5.0 (IIS) installed and configured
  2. If your development computer is a different computer than the server, you must have a valid network or Internet connection to the server that hosts the ASP pages.
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Microsoft Visual Basic 6 Project Setup and Code

  1. Start Visual Basic, and then start a new ActiveX DLL project.
  2. Name the project ASPFileUpload.
  3. Change the name of Class1 to File.
  4. On the Project menu, click References.
  5. In the References dialog box, click to select the following options, and then click OK:
    • Visual Basic For Applications
    • Visual Basic runtime objects and procedures
    • Visual Basic objects and procedures
    • OLE Automation
    • COM+ Services Type Library
    • Microsoft Active Server Pages Object Library
    • Microsoft Scripting Runtime
  6. On the Project menu, click ASPFileUpload Properties.
  7. In the Project Properties dialog box, click to select Unattended Execution and Retained In Memory, and then click OK.
  8. Paste the following code to File.cls:
    Option ExplicitConst ERR_INVALID_FILENAME = vbObjectError + 1000Const ERR_INVALID_TARGET = vbObjectError + 1001Const ERR_FILE_EXISTS = vbObjectError + 1002Const ERR_UPLOAD_CALLED = vbObjectError + 1003Const VB_ERR_PATH_NOT_FOUND = 76Private m_objContext As ObjectContextPrivate m_objRequest As ASPTypeLibrary.RequestPrivate m_strTarget As StringPrivate m_strFileName As StringPrivate m_blnOverWrite As BooleanPrivate m_blnUploaded As BooleanPrivate m_lngTotalBytes As Long'All other form elements go here.Private m_formCol As Scripting.DictionaryImplements ObjectControlPrivate Function ObjectControl_CanBePooled() As Boolean  ObjectControl_CanBePooled = FalseEnd FunctionPrivate Sub ObjectControl_Activate()  Set m_objContext = GetObjectContext()  Set m_objRequest = m_objContext("Request")  Set m_formCol = New Scripting.DictionaryEnd SubPrivate Sub ObjectControl_Deactivate()  Set m_objContext = Nothing  Set m_objRequest = Nothing  Set m_formCol = NothingEnd SubPublic Sub Upload()    Const DEFAULT_CHUNK_SIZE = 262144 '256kb    Dim bytBeginOfChunk() As Byte  Dim bytEndOfChunk() As Byte  Dim bytBeginOfName() As Byte  Dim bytEndOfName() As Byte  Dim bytBeginOfFile() As Byte  Dim bytEndOfFile() As Byte  Dim bytBeginOfValue() As Byte  Dim bytEndOfValue() As Byte  Dim bytName() As Byte  Dim bytValue() As Byte  Dim bytThisChunk() As Byte  Dim bytFileName() As Byte  Dim lngBeginOfChunk As Long  Dim lngEndOfChunk As Long    Dim lngBeginOfAttribute As Long  Dim lngEndOfAttribute As Long  Dim lngBeginOfValue As Long  Dim lngEndOfValue As Long  Dim blnEndOfData As Boolean  Dim lngChunkSize As Long  Dim lngBytesLeft As Long  Dim lngFileNum As Long  Dim strFileName As String    On Error GoTo UploadErr    If Uploaded Then    Err.Raise ERR_UPLOAD_CALLED, App.Title, "The Upload method has already been called."  End If       bytBeginOfChunk = StrConv("-----------------------------", vbFromUnicode)  bytEndOfChunk = StrConv("-----------------------------", vbFromUnicode)    bytBeginOfName = StrConv("name=", vbFromUnicode) & ChrB(34)  bytEndOfName = ChrB(34)    bytBeginOfFile = StrConv("filename=", vbFromUnicode) & ChrB(34)  bytEndOfFile = ChrB(34)    bytBeginOfValue = ChrB(13) & ChrB(10) & ChrB(13) & ChrB(10)  bytEndOfValue = ChrB(13) & ChrB(10) & StrConv("-----------------------------", vbFromUnicode)       'Initialize the chunk size.  If m_objRequest.TotalBytes <= DEFAULT_CHUNK_SIZE Then    lngChunkSize = m_objRequest.TotalBytes  Else    lngChunkSize = DEFAULT_CHUNK_SIZE  End If      'Get the chunk from the request object.  bytThisChunk = m_objRequest.BinaryRead(CVar(lngChunkSize))  'Initialize the value.  lngBeginOfChunk = 1    'Repeat until the end of the data.  Do While Not blnEndOfData    'Begin the chunk.    lngBeginOfChunk = InStrB(lngBeginOfChunk, bytThisChunk, bytBeginOfChunk) + UBound(bytBeginOfChunk)        'Get name of the item.    lngBeginOfAttribute = InStrB(lngBeginOfChunk, bytThisChunk, bytBeginOfName) + UBound(bytBeginOfName) + 1    lngEndOfAttribute = InStrB(lngBeginOfAttribute, bytThisChunk, bytEndOfName)    bytName = MidB(bytThisChunk, lngBeginOfAttribute, lngEndOfAttribute - lngBeginOfAttribute)        'Get the value of the item.    lngBeginOfValue = InStrB(lngEndOfAttribute, bytThisChunk, bytBeginOfValue, vbBinaryCompare) + UBound(bytBeginOfValue) + 1    lngEndOfValue = InStrB(lngBeginOfValue, bytThisChunk, bytEndOfValue, vbBinaryCompare)        If lngEndOfValue = 0 Then      'The item extends the past current chunk.      bytValue = MidB(bytThisChunk, lngBeginOfValue, lngChunkSize)    Else      'The item value exists in the current chunk.      bytValue = MidB(bytThisChunk, lngBeginOfValue, lngEndOfValue - lngBeginOfValue)    End If        If UCase(StrConv(bytName, vbUnicode)) = "FILE" Then      lngBeginOfAttribute = InStrB(lngBeginOfChunk, bytThisChunk, bytBeginOfFile, vbBinaryCompare) + UBound(bytBeginOfFile) + 1      lngEndOfAttribute = InStrB(lngBeginOfAttribute, bytThisChunk, bytEndOfFile, vbBinaryCompare)            bytFileName = MidB(bytThisChunk, lngBeginOfAttribute, lngEndOfAttribute - lngBeginOfAttribute)            If UBound(bytFileName) < 0 Or UBound(bytValue) < 0 Then        Err.Raise ERR_INVALID_FILENAME, App.Title, "Invalid File Name."      End If            If Me.Target = "" Then        Err.Raise ERR_INVALID_TARGET, App.Title, "Invalid Target."      End If            'Use the original file name.      If Me.FileName = "" Then              'Trim the path from the file name.        While InStrB(1, bytFileName, StrConv("\", vbFromUnicode), vbBinaryCompare) > 0          bytFileName = MidB(bytFileName, InStrB(1, bytFileName, StrConv("\", vbFromUnicode)) + 1)        Wend                'Set the property.        Me.FileName = StrConv(bytFileName, vbUnicode)                'Convert the byte to Unicode.        strFileName = Me.Target & Me.FileName             Else        strFileName = Me.Target & Me.FileName      End If            'Check for overwrite.      If Me.OverWrite Then        'This is the hack check. Make sure that wildcard characters cannot be used.        If Not InStr(1, strFileName, "*") Then          If FileExists(strFileName) Then            Kill strFileName          End If        Else          Err.Raise ERR_INVALID_FILENAME, App.Title, "The specified file name appears to be invalid."        End If      Else        If FileExists(strFileName) Then          Err.Raise ERR_FILE_EXISTS, App.Title, "The file already exists."        End If      End If            lngFileNum = FreeFile            Open strFileName For Binary Access Write As #lngFileNum            'Write the file to the destination directory.      Put #lngFileNum, , bytValue      'This chunk is empty. Therefore, get a new chunk.      lngBytesLeft = m_objRequest.TotalBytes - lngChunkSize              'Start the chunking machine.      Do While lngBytesLeft > 0              'Get a new chunk.        bytThisChunk = m_objRequest.BinaryRead(CVar(lngChunkSize))                            lngEndOfValue = InStrB(1, bytThisChunk, bytEndOfValue, vbBinaryCompare)                    If lngEndOfValue > 0 Then            'The item value exists in the current chunk.            bytThisChunk = MidB(bytThisChunk, 1, lngEndOfValue - 1)          End If                    'Append the chunk to the file.          Put #lngFileNum, , bytThisChunk                    lngBytesLeft = lngBytesLeft - lngChunkSize                    If lngBytesLeft < lngChunkSize Then            lngChunkSize = lngBytesLeft          End If        Loop                Close #lngFileNum                TotalBytes = FileLen(strFileName)             ' Exit Do     Else      If UCase(StrConv(bytName, vbUnicode)) = "SAVEAS" Then       Me.FileName = StrConv(bytValue, vbUnicode)      Else        'form field other than file, such as textboxes        If UBound(bytValue) > 0 And UBound(bytName) > 0 Then         m_formCol.Add StrConv(bytName, vbUnicode), StrConv(bytValue, vbUnicode)       Else        m_formCol.Add StrConv(bytName, vbUnicode), ""       End If      End If     End If        'Get the next chunk.    lngBeginOfChunk = lngEndOfValue        If InStrB(lngBeginOfChunk, bytThisChunk, bytBeginOfName, vbBinaryCompare) = 0 Then      blnEndOfData = True    End If  Loop  Uploaded = True    Exit Sub  UploadErr:    If Err.Number = VB_ERR_PATH_NOT_FOUND Then    Err.Raise ERR_INVALID_TARGET, App.Title, "The Target specified does not exist."  Else    Err.Raise Err.Number, Err.Source, Err.Description  End IfEnd SubPublic Property Get Form() As Collection    Set Form = m_formColEnd PropertyPublic Property Get FileName() As String  FileName = m_strFileNameEnd PropertyPublic Property Let FileName(ByVal strNewValue As String)  If Uploaded Then    Err.Raise ERR_UPLOAD_CALLED, App.Title, "The Upload method has already been called."  Else    m_strFileName = strNewValue  End IfEnd PropertyPublic Property Get OverWrite() As Boolean  OverWrite = m_blnOverWriteEnd PropertyPublic Property Let OverWrite(ByVal blnNewValue As Boolean)  If Uploaded Then    Err.Raise ERR_UPLOAD_CALLED, App.Title, "The Upload method has already been called."  Else    m_blnOverWrite = blnNewValue  End IfEnd PropertyPrivate Property Get Uploaded() As Boolean  Uploaded = m_blnUploadedEnd PropertyPrivate Property Let Uploaded(ByVal blnNewValue As Boolean)  m_blnUploaded = blnNewValueEnd PropertyPublic Property Get Target() As String  Target = m_strTargetEnd PropertyPublic Property Let Target(ByVal NewValue As String)  If Uploaded Then    Err.Raise ERR_UPLOAD_CALLED, App.Title, "The Upload method has already been called."  Else    m_strTarget = NewValue  End IfEnd PropertyPrivate Function FileExists(ByVal FileName As String) As Boolean  On Error GoTo FileExistsErr    FileLen FileName  FileExists = True  Exit Function  FileExistsErr:  If Err.Number = VB_ERR_PATH_NOT_FOUND Then    FileExists = False  End IfEnd FunctionPublic Property Get TotalBytes() As Long  TotalBytes = m_lngTotalBytesEnd PropertyPrivate Property Let TotalBytes(ByVal NewValue As Long)  m_lngTotalBytes = NewValueEnd Property
  9. Compile the project
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ASP Code

  1. Paste the following code to an editor such as Notepad or Microsoft Visual Interdev, and then save it as PostFile.asp:
    <%@ Language=VBScript %><html><head></head><body><form enctype="multipart/form-data" action="uploadfile.asp" method="post" name="main1"><input name="file" type="file" size="50"><INPUT type="text" id=text1 name=text1><INPUT type="text" id=text2 name=text2><input name="submit" type="submit" value="Upload"></form></body></html>
  2. Copy the following code to an editor such as Notepad or Visual Interdev, and then save it as UploadFile.asp:
    <%@ Language=VBScript %><%  '//////////////////////////////////////////////////////////////////////////////////  '//  ASPFileUpload.File API  '//    '//  Properties  '//     FileName  '//       - Read/Write   '//       - The file will be saved with this file name.   '//       - This property can only be set before calling Upload.  '//       - If no value is specified, the original file name  '//       - in the HTTP post will be used.  '//       '//     OverWrite  '//       - Read/Write  '//       - This property can only be set before calling Upload.  '//       - If set to false and if the destination file exists, an error  '//       - is raised. The default value is False.  '//       '//     Target   '//       - Read/Write  '//       - The file will be written to this folder.  '//       - This property can only be set before calling Upload.  '//       - There is no default value for this property and it is required.  '//         '//      Form  '//        - ReadOnly  '//        - Scripting.Dictionary object  '//        - Can access a specific item by using aspfileupload.Form("item").  '//        - Acts like the asp form collection.  '//        - Can enumerate all values in a collection with for each.  '//        - Only filled after the Upload method is called.  '//           '//  Methods  '//     Upload  '//       - This method parses the HTTP Post and writes the file.  '//    '//  Other  '//    - ASPFileUpload requires COM+  '//    - Any call to the Request.Form() collection will cause the Upload  '//      method to fail as the method references the Binary contents of the  '//      Request object through the Request.BinaryRead method.   '//    - Also, if you access a variable in the Request collection without   '//      specifying the subcollection that it belongs to, the Request.Form collection   '//      may be searched. This causes an error in the Upload method.  '//        '//////////////////////////////////////////////////////////////////////////////////    Dim strMsg 'As String   ' On Error Resume Next  dim fuFile  set fuFile = server.CreateObject("aspFileupload.file")    'Set the destination folder.  fuFile.Target = "C:\TEMP\AspFileUpload\"  fuFile.Upload    If Err.number = 0 Then    strMsg = fuFile.FileName  & " was uploaded successfully."  Else    strMsg = "An error occurred when uploading your file: " & Err.Description   End If  for each o in fuFile.Form	Response.Write o  & "<BR>"		next		Response.Write fuFile.Form.item("text1") & "  :  " & fuFile.Form.item("text2")'  Response.Write Request.Form("test") set fufile = nothing%><html><head></head><body><%=strMsg%></body></html>
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Set Up the Server

  1. Create a folder on the Web server that will receive the uploaded files, such as C:\TEMP\AspFileUpload.
  2. Copy the ASPFileUpload.dll file to the Web server, and then register it by using the following command at the command prompt:
    regsvr32 PathToDLL\ASPFileUpload.dll
  3. Apply file permissions (Write access) for the users who you want to be able to upload the files.
  4. Click Start, point to Settings, and then click Control Panel.
  5. In Control Panel, click Administrative Tools, and then click Component Services to open Component Services in the Microsoft Management Console (MMC).
  6. Expand the Component Services node, the Computers node, the My Computer node, and the COM+ Applications node.
  7. Right-click the node, point to New, and then click Application.
  8. In the Install or Create a New Application dialog box, click Create an empty application, name the application, make sure that you click to select Server application, and then click Next.
  9. In the Set Application Identity dialog box, click This User, and then type the credentials for the appropriate user account. The user account must have Write access to the folder that will receive the uploaded file.
  10. Click Finish.
  11. Expand the node that you have just created for this application.
  12. Right-click the nod, point to New, and then click Component.
  13. Click Install new components, and locate the folder where you have saved and registered the .dll file, click the file, click Next, and then click Finish.
  14. Copy the Postfile.asp file and the Uploadfile.asp file to your Web root folder. By default, the Web root folder is C:\Inetpub\Wwwroot.
  15. Edit the target folder of Uploadfile.asp to reflect the folder that you created in step 1. The target folder assignment is located in the following line of code:
    fuFile.Target = "C:\TEMP\AspFileUpload\"					
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Upload a File

  1. In a Web browser, open the Postfile.asp page at the following URL:
  2. Select a file that you want to upload, and then click Upload.
  3. Check your upload folder. The file that you uploaded appears in this folder.
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  • If you do not type a file name, and if you try to submit the Postfile.asp page, you receive a generic, server-side error message. You may want to modify the code to provide a more friendly error message on either the client side or on the server side.
  • If you require high volume upload capacity, Microsoft recommends that you buy or build a compiled, multithreaded component that can more efficiently handle the load than this Visual Basic component.
  • A potential security risk exists whenever you allow users to upload files to your Web server. This is especially true if your server is on the Internet, and if you allow anonymous uploads. You must correctly configure Windows permissions and IIS user authentication to make sure that you give users only the access that they require. This is important so that you do not allow users a way to gain access by bypassing the security controls of your system.
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Article ID: 299692 - Last Review: 01/04/2012 20:46:00 - Revision: 7.0

  • Microsoft Active Server Pages 4.0
  • Microsoft Internet Information Services 5.0
  • kbaspobj kbcodesnippet kbconfig kbdeployment kbfile kbfso kbGuidelines kbhowto kbsample kbscript kbsecurity kbserver kbsetup kbwebserver KB299692