RestSharp in Visual basic 6 - asp.net

Question

I have this code in Visual Basic .net and I would like to make the same thing in Visual Basic 6. The code upload an image to a given URL. I have to use Rest protocol because the server I upload the image request it.
Dim res As New RestSharp.RestRequest("URL_OF_SERVER", RestSharp.Method.POST)
res.AddFile("file", "File_location_on_PC")
Dim restClient As New RestSharp.RestClient()
Dim r As New RestSharp.RestResponse
r = restClient.Execute(res)
Is it posible to do the same Rest Protocol in Visual Basic 6?
EDIT 1: I HAVE TRIED THIS BUT AN ERROR HAPPENS
Dim xmlhttp As MSXML2.XMLHTTP30
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 NombreArchivo 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=""image002""; filename=""C:\image002.jpg" & _
"--" & STR_BOUNDARY & "--"
'--- post
Set xmlhttp = New MSXML2.XMLHTTP30
With xmlhttp
.Open "POST", Url, False
.setRequestHeader "Content-Type", "multipart/form-data; boundary=" & STR_BOUNDARY
.send pvToByteArray(sPostData)
End With
Private Function pvToByteArray(sText As String) As Byte()
pvToByteArray = StrConv(sText, vbFromUnicode)
End Function
ERROR :
responseText
{"message":"file.not_found","error":"There is no file in request.","status":400,"cause":[]}
Thanks!

Answer 1

If you need just to post a file here is a simple function
Private Sub pvPostFile(sUrl As String, sFileName As String, Optional ByVal bAsync As Boolean)
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)
End With
End Sub
Private Function pvToByteArray(sText As String) As Byte()
pvToByteArray = StrConv(sText, vbFromUnicode)
End Function
You can switch to MSXML2.ServerXMLHTTP to be able to use its SetTimeouts method if your file is large enough and timeouts in 30 sec.

Answer 2

You can create a COM callable wrapper (CCW) for the RestSharp assembly - see this URL for details of how to do this:
http://msdn.microsoft.com/en-us/library/ms973802.aspx
Once it is registered, you can use RestSharp from VB6.