I am trying to upload a file with https://file.io with VBA in Excel, using their Api (https://www.file.io/#one, see below).

I've found this thread how to upload file to file.io and get link, however, I didn't know how to accurately transfer it from C# to VBA.

The syntax on File.io is:

$ curl -F "file=@test.txt" https://file.io
{"success":true,"key":"2ojE41","link":"https://file.io/2ojE41","expiry":"14 days"}
$ curl https://file.io/2ojE41 
This is a test
$ curl https://file.io/2ojE41
{"success":false,"error":404,"message":"Not Found"}

My current code looks as following:

Set objhttp = CreateObject("MSXML2.ServerXMLHTTP")
URL = "https://file.io"
objhttp.Open "post", URL, False
objhttp.setRequestHeader "Content-type", "application/json" 
objhttp.Send ("file=@C:/Users/me/Downloads/image.jpg")
Debug.Print objhttp.responsetext

My Responsetext says:

{"success":false,"error":400,"message":"Trouble uploading file"}

I'm not even sure about the "@" in the Path or if there's normally a standard folder to be used, etc. Many thanks in advance! All help is appreciated.

Steps to post multipart/form-data using XmlHttp VBA

1. Use Chrome/Firefox/Fiddler to watch HTTP request.
2. First manually upload the file and see all request & response which browser does
   (especially xhr, document request with status code 200)
3. Pass the cookies, parameters in the post request

I have used chrome browser in this case and the image below shows the parameter which the browser sends along in the request.

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 Sub UploadFilesUsingVBA()
     'this proc will upload below files to https://file.io/
          '  png, jpg, txt

        Dim fileFullPath As String
        fileFullPath = "C:\Users\santosh\Desktop\abcd.txt"

        POST_multipart_form_data fileFullPath
    End Sub

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Confirmation message in case of successful file upload

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Private Function GetGUID() As String
    ' Generate uuid version 4 using VBA
    GetGUID = WorksheetFunction.Concat(WorksheetFunction.Dec2Hex(WorksheetFunction.RandBetween(0, 4294967295#), 8), "-", WorksheetFunction.Dec2Hex(WorksheetFunction.RandBetween(0, 65535), 4), "-", WorksheetFunction.Dec2Hex(WorksheetFunction.RandBetween(16384, 20479), 4), "-", WorksheetFunction.Dec2Hex(WorksheetFunction.RandBetween(32768, 49151), 4), "-", WorksheetFunction.Dec2Hex(WorksheetFunction.RandBetween(0, 65535), 4), WorksheetFunction.Dec2Hex(WorksheetFunction.RandBetween(0, 4294967295#), 8))

End Function

Private Function GetFileSize(fileFullPath As String) As Long

    Dim lngFSize As Long, lngDSize As Long
    Dim oFO As Object, OFS As Object

    lngFSize = 0
    Set OFS = CreateObject("Scripting.FileSystemObject")

    If OFS.FileExists(fileFullPath) Then
        Set oFO = OFS.getFile(fileFullPath)
        GetFileSize = oFO.Size
    Else
        GetFileSize = 0
    End If

    Set oFO = Nothing
    Set OFS = Nothing
End Function



Private Function ReadBinary(strFilePath As String)
    Dim ado As Object, bytFile
    Set ado = CreateObject("ADODB.Stream")
    ado.Type = 1
    ado.Open
    ado.LoadFromFile strFilePath
    bytFile = ado.Read
    ado.Close

    ReadBinary = bytFile

    Set ado = Nothing
End Function


Private Function toArray(str)
    Dim ado As Object
     Set ado = CreateObject("ADODB.Stream")
     ado.Type = 2
     ado.Charset = "_autodetect"
     ado.Open
     ado.WriteText (str)
     ado.Position = 0
     ado.Type = 1
     toArray = ado.Read()
     Set ado = Nothing
End Function


Sub POST_multipart_form_data(filePath As String)

    Dim oFields As Object, ado As Object
    Dim sBoundary As String, sPayLoad As String, GUID As String
    Dim fileType As String, fileExtn As String, fileName As String
    Dim sName As Variant

    fileName = Right(filePath, Len(filePath) - InStrRev(filePath, "\"))
    fileExtn = Right(filePath, Len(fileName) - InStrRev(fileName, "."))

    Select Case fileExtn
     Case "png"
        fileType = "image/png"
     Case "jpg"
        fileType = "image/jpeg"
     Case "txt"
        fileType = "text/plain"
    End Select

    Set oFields = CreateObject("Scripting.Dictionary")
    With oFields
        .Add "qquuid", GetGUID
        .Add "qqtotalfilesize", GetFileSize(filePath)
    End With

    sBoundary = String(27, "-") & "7e234f1f1d0654"
    sPayLoad = ""
    For Each sName In oFields
        sPayLoad = sPayLoad & "--" & sBoundary & vbCrLf
        sPayLoad = sPayLoad & "Content-Disposition: form-data; name=""" & sName & """" & vbCrLf & vbCrLf
        sPayLoad = sPayLoad & oFields(sName) & vbCrLf
    Next

    sPayLoad = sPayLoad & "--" & sBoundary & vbCrLf
    sPayLoad = sPayLoad & "Content-Disposition: form-data; name=""file""; " & "filename=""" & fileName & """" & vbCrLf
    sPayLoad = sPayLoad & "Content-Type: " & fileType & vbCrLf & vbCrLf & vbCrLf & vbCrLf & vbCrLf



     sPayLoad = sPayLoad & "--" & sBoundary & "--"


      Set ado = CreateObject("ADODB.Stream")
      ado.Type = 1
      ado.Open
      ado.Write toArray(sPayLoad)
      ado.Write ReadBinary(filePath)
      ado.Position = 0

    With CreateObject("MSXML2.ServerXMLHTTP")
        .Open "POST", "https://file.io", False
        .SetRequestHeader "Content-Type", "multipart/form-data; boundary=" & sBoundary
        .Send (ado.Read())
        MsgBox .responseText
    End With

End Sub

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Links which helped to answer this question
1. https://stackoverflow.com/a/43266809/2227085
2. https://wqweto.wordpress.com/