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Excel VBA how to read in text file from web (not cached)?


I have been using the following code to read in a text file from the web:

'import the text file into a string
Function DownloadTextFile(URL As String) As String
On Error GoTo Err_GetFromWebpage

Dim objWeb As Object
Dim strXML As String

 ' Instantiate an instance of the web object
Set objWeb = CreateObject("Microsoft.XMLHTTP")

 ' Pass the URL to the web object, and send the request
objWeb.Open "GET", URL, False
objWeb.send

 ' Look at the HTML string returned
strXML = objWeb.responseText

DownloadTextFile = strXML


End_GetFromWebpage:
 ' Clean up after ourselves!
Set objWeb = Nothing
Exit Function

Err_GetFromWebpage:
 ' Just in case there's an error!
MsgBox Err.Description & " (" & Err.Number & ")"
Resume End_GetFromWebpage

End Function

It worked fine the first time, but when I make changes to the text file, it's not being reflected in the returned string. It's as if Excel is caching the file. What can I do to fix this? Thanks!


Solution

  • In addition to setting the request headers, as suggested by @dee, I've also changed "Microsoft.XMLHTTP" to "Msxml2.ServerXMLHTTP", and now it works! Here is the final code:

    'import the text file into a string
    Function DownloadTextFile(URL As String) As String
        On Error GoTo Err_GetFromWebpage
    
        Dim objWeb As Object
        Dim strXML As String
    
         ' Instantiate an instance of the web object
        Set objWeb = CreateObject("Msxml2.ServerXMLHTTP")
    
         ' Pass the URL to the web object
        objWeb.Open "GET", URL, False
    
        'don't cache the file
        objWeb.setRequestHeader "Content-Type", "text/xml"
        objWeb.setRequestHeader "Cache-Control", "no-cache"
        objWeb.setRequestHeader "Pragma", "no-cache"
    
        'send the request
        objWeb.send
    
         ' Look at the HTML string returned
        strXML = objWeb.responseText
    
        DownloadTextFile = strXML
    
        End_GetFromWebpage:
         ' Clean up after ourselves!
        Set objWeb = Nothing
        Exit Function
    
        Err_GetFromWebpage:
         ' Just in case there's an error!
        MsgBox Err.Description & " (" & Err.Number & ")"
        Resume End_GetFromWebpage 
    
    End Function