Using VBA to Fix the Unauthorized Error When Uploading Files to Google Drive

Uploading Files to Google Drive via VBA - Solving the Unauthorized Error

VBA with Google Drive API and token-based authentication

Sub GoogleDriveAPI()
    Const reqURL As String = "https://www.googleapis.com/upload/drive/v3/files?uploadType=multipart"
    Const Token As String = "api-token" ' Replace with your actual API token
    Dim content() As Byte, fPath As String, FileName As String
    Dim file_metadata As String
    fPath = "D:\" ' Path to the file to be uploaded
    FileName = "M.pdf" ' The file name
    file_metadata = "{'name':'" & FileName & "'}"
    ' Boundary for separating file parts
    Dim Boundary, part As String, ado As Object
    Boundary = CreateBoundary()
    part = BuildMultipartContent(Boundary, file_metadata, fPath, FileName)
    ' Create HTTP request for Google Drive API
    Dim req As New MSXML2.XMLHTTP60
    Set req = New MSXML2.ServerXMLHTTP60
    With req
        .Open "POST", reqURL, False
        .setRequestHeader "Authorization", "Bearer " & Token
        .setRequestHeader "Content-Type", "multipart/related; boundary=" & Boundary
        .send ado.Read
    End With
    If req.Status = 200 Then
        Debug.Print req.responseText ' Success
    Else
        MsgBox req.Status & ": " & req.statusText ' Error handling
    End If
End Sub

Function CreateBoundary() As String
    Dim s As String
    Dim n As Integer
    For n = 1 To 16
        s = s & Chr(65 + Int(Rnd * 25))
    Next
    CreateBoundary = s & CDbl(Now)
End Function

Function BuildMultipartContent(Boundary As String, metadata As String, fPath As String, FileName As String) As String
    Dim part As String
    part = "--" & Boundary & vbCrLf
    part = part & "Content-Type: application/json; charset=UTF-8" & vbCrLf & vbCrLf
    part = part & metadata & vbCrLf
    part = part & "--" & Boundary & vbCrLf
    part = part & "Content-Type: application/pdf" & vbCrLf
    part = part & "Content-Transfer-Encoding: binary" & vbCrLf & vbCrLf
    part = part & ReadBinaryFile(fPath, FileName) & vbCrLf
    part = part & "--" & Boundary & "--"
    BuildMultipartContent = part
End Function

Function ReadBinaryFile(fPath As String, FileName As String) As String
    Dim ado As Object
    Set ado = CreateObject("ADODB.Stream")
    ado.Type = 1 ' Binary mode
    ado.Open
    ado.LoadFromFile fPath & FileName
    ReadBinaryFile = ado.Read
    ado.Close
End Function

Alternative Approach: Uploading Files via Google Drive API using Python

Python with Google Drive API and OAuth 2.0 for authentication

from google.oauth2 import service_account
from googleapiclient.discovery import build
from googleapiclient.http import MediaFileUpload

def upload_to_drive():
    credentials = service_account.Credentials.from_service_account_file('path-to-credentials.json')
    service = build('drive', 'v3', credentials=credentials)

    file_metadata = {'name': 'M.pdf'}
    media = MediaFileUpload('D:/M.pdf', mimetype='application/pdf')

    file = service.files().create(body=file_metadata, media_body=media, fields='id').execute()
    print('File ID: %s' % file.get('id'))

if __name__ == '__main__':
    upload_to_drive()

Frequently Asked Questions about Uploading Files to Google Drive using VBA

1. How do I resolve the "Unauthorized" error in my VBA script?
2. Ensure that the API token you are using has the correct permissions and is not expired. You can refresh the token or use the OAuth 2.0 flow to generate a new one.
3. What is the purpose of the boundary in the multipart request?
4. The boundary is a unique string that separates different parts of the multipart data. It helps the API differentiate between file metadata and file content when using multipart/related requests.
5. Why is my file not uploading correctly?
6. This could be due to incorrect formatting of the multipart data or an invalid file path. Use ADODB.Stream to read the file in binary format and ensure the path is correct.
7. How do I check the response from Google Drive API?
8. You can use Debug.Print to display the server's response in the immediate window of the VBA editor. This helps in understanding if the request was successful or if there was an error.
9. What are some common mistakes when uploading files to Google Drive using VBA?
10. Some common mistakes include using an expired API token, incorrect formatting of the HTTP request, or not including the necessary Authorization headers.

Wrapping Up the Guide on VBA Google Drive Uploads

In conclusion, successfully uploading files from Excel to Google Drive via VBA requires careful attention to authentication and formatting. The use of an accurate token and correct API settings is crucial for avoiding common errors like "Unauthorized."

Furthermore, ensuring the correct construction of multipart requests and handling binary file data efficiently will make the process smooth and error-free. With the right approach and error-handling techniques, these tasks can be automated seamlessly in Excel.