Uploading a file to Azure Blob Storage using VBA and MS XMLHTTP

问题

I've been trying to upload file to Azure storage using VBA in Microsoft Access but so far without success.

I have had a good search around and have found some code which looks promising but I can't get it to work. Seems like many others have been looking for a similar solution or help with working with Azure from VBA.

This is the code;

Private Function pvPostFile(sUrl As String, sFileName As String, Optional ByVal bAsync As Boolean) As String
Const STR_BOUNDARY  As String = "3fbd04f5-b1ed-4060-99b9-fca7ff59c113"
Dim nFile           As Integer
Dim baBuffer()      As Byte
Dim sPostData       As String

'--- read file
nFile = FreeFile
Open sFileName For Binary Access Read As nFile
If LOF(nFile) > 0 Then
    ReDim baBuffer(0 To LOF(nFile) - 1) As Byte
    Get nFile, , baBuffer
    sPostData = StrConv(baBuffer, vbUnicode)
End If
Close nFile
'--- prepare body
sPostData = "--" & STR_BOUNDARY & vbCrLf & _
    "Content-Disposition: form-data; name=""uploadfile""; filename=""" & Mid$(sFileName, InStrRev(sFileName, "\") + 1) & """" & vbCrLf & _
    "Content-Type: application/octet-stream" & vbCrLf & vbCrLf & _
    sPostData & vbCrLf & _
    "--" & STR_BOUNDARY & "--"
'--- post
With CreateObject("Microsoft.XMLHTTP")
    .Open "POST", sUrl, bAsync
    .SetRequestHeader "Content-Type", "multipart/form-data; boundary=" & STR_BOUNDARY
    .Send pvToByteArray(sPostData)
    If Not bAsync Then
        pvPostFile = .ResponseText
    End If
End With
End Sub

Private Function pvToByteArray(sText As String) As Byte()
    pvToByteArray = StrConv(sText, vbFromUnicode)
End Function

(Thanks to - https://wqweto.wordpress.com/2011/07/12/vb6-using-wininet-to-post-binary-file/)

When I try this code using my azure storage URL in the form

https://XXXXX.blob.core.windows.net/

and a filename (C:\Temp\Test.txt) I get the following error;

<?xml version="1.0" encoding="utf-8"?><Error><Code>UnsupportedHttpVerb</Code><Message>The resource doesn't support specified Http Verb.

I suspect there's a problem in the header or post data rather than the VBA and this is not really my area.

Any help greatly appreciated.

回答1:

I came across this post as I'm searching the same answer for uploading images to Azure Blob Storage. I took me 2 days to get the answer. And the code posted above did help me to partly solve the problem.

I would like to post my solution here in case anyone else is looking for the same answer.

Before you can use the code below, you need to get the Shared Access Signature (SAS) from your Azure portal (manage panel). You should be able to google the answers on this.

Public Sub UploadAfIle(sUrl As String, sFileName As String)
    Dim adoStream As Object
    Set adoStream = CreateObject("ADODB.Stream")
    adoStream.Mode = 3          ' read write
    adoStream.Type = 1          ' adTypeBinary
    adoStream.Open
    adoStream.LoadFromFile (sFileName)
    With CreateObject("Microsoft.XMLHTTP")
        adoStream.Position = 0
        .Open "PUT", sUrl, False
        .setRequestHeader "Content-Length", "0" 'this is not a must
        .setRequestHeader "x-ms-blob-type", "BlockBlob"
        .Send adoStream.Read(adoStream.Size)
    End With
    Set adoStream = Nothing
End Sub

sURL is a URL looks like (I'm in China so the Host is different): https://myaccount.blob.core.chinacloudapi.cn/products/newimagename.jpg?sv=2016-05-31&ss=bfpq&srt=dco&sp=rydlscup&se=2017-07-30T18:40:26Z&st=2017-07-28T10:40:26Z&spr=https&sig=mJgDyECayITp0ivVrD4Oug%2Bz%2chN7Wpo2nNtcn0pYRCU%4d

The one bolded is the SAS token you generated from Azure.

回答2:

Worth noting the format of the sUrl in SiliconXu's answer is made up of 3 parts, I didn't realise at first so got a sore head for a while!!

1) Azure blob container URL (from the properties in the Storage Explorer) 2) the filename (this is the part I omitted by mistake) 3) Shared Access Signature

So is built like this

sURL = destination_folder & "/" & local_file_name & "?" & conn_SAS

I don't have the reputation require to comment directly below that answer

Great code though, as soon as I worked out the format of the sURL it worked like a dream

回答3:

Azure Storage Service uses private key authentication. Since VBA runs on the end user's machine you are exposing yourself to a whole slew of risks associated with that key getting into the wild. I would recommend rethinking the whole premise of going directly from VBA to Azure Storage and utilize your own WebAPI to handle storing data to Blob.

This would have the dual benefit of:

1) making it easier to integrate with from VBA and

2) protecting your Azure Storage private key behind a component of your solution that doesn't get deployed to the end user's machine.

来源：https://stackoverflow.com/questions/33285667/uploading-a-file-to-azure-blob-storage-using-vba-and-ms-xmlhttp

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vba