[SOLVED] Upload file to Google Drive from web file chooser using chilkat

I am developing a web application in Xojo and I use the Chilkat plugin to manage the Google Drive cloud but I am a bit lost with uploading files to the Google cloud with this plugin. In my web application I have added a file selector (to select an excel file) and added a button that executes the upload method. I have based this on an example on Chilkat's own website which has the following code:

Dim success As Boolean
success = True

//  This example requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

//  This example uses a previously obtained access token having permission for the
//  Google Drive scope.
//  See Get Google Drive OAuth2 Access Token

Dim gAuth As New Chilkat.AuthGoogle
gAuth.AccessToken = "GOOGLE-DRIVE-ACCESS-TOKEN"

Dim rest As New Chilkat.Rest

//  Connect using TLS.
Dim bAutoReconnect As Boolean
bAutoReconnect = True
success = rest.Connect("www.googleapis.com",443,True,bAutoReconnect)

//  Provide the authentication credentials (i.e. the access token)
success = rest.SetAuthGoogle(gAuth)

//  -------------------------------------------------------------------------
//  A multipart upload to Google Drive needs a multipart/related Content-Type
success = rest.AddHeader("Content-Type","multipart/related")

//  Specify each part of the request.

//  The 1st part is JSON with information about the file.
rest.PartSelector = "1"
success = rest.AddHeader("Content-Type","application/json; charset=UTF-8")

//  Construct the JSON that will contain the metadata about the file data to be uploaded...
Dim json As New Chilkat.JsonObject
success = json.AppendString("name","starfish.jpg")
success = json.AppendString("description","A picture of a starfish.")
success = json.AppendString("mimeType","image/jpeg")

//  To place the file in a folder, we must add a parents[] array to the JSON
//  and add the folder ID.
//  In a previous example (see Lookup Google Drive Folder ID
//  we showed how to find the folder ID for a folder in Google Drive.

//  Use the folder ID we already looked up..
Dim folderId As String
folderId = "1Fksv-TfA1ILii1YjXsNa1-rDu8Cdrg72"
Dim parents As Chilkat.JsonArray
parents = json.AppendArray("parents")
success = parents.AddStringAt(-1,folderId)

success = rest.SetMultipartBodyString(json.Emit())

//  The 2nd part is the file content, which will contain the binary image data.
rest.PartSelector = "2"
success = rest.AddHeader("Content-Type","image/jpeg")

Dim jpgBytes As New Chilkat.BinData
success = jpgBytes.LoadFile("qa_data/jpg/starfish.jpg")

//  Add the data to our upload
success = rest.SetMultipartBodyBd(jpgBytes)

Dim jsonResponse As String
jsonResponse = rest.FullRequestMultipart("POST","/upload/drive/v3/files?uploadType=multipart")
If (rest.LastMethodSuccess <> True) Then
    System.DebugLog(rest.LastErrorText)
    Return
End If

//  A successful response will have a status code equal to 200.
If (rest.ResponseStatusCode <> 200) Then
    System.DebugLog("response status code = " + Str(rest.ResponseStatusCode))
    System.DebugLog("response status text = " + rest.ResponseStatusText)
    System.DebugLog("response header: " + rest.ResponseHeader)
    System.DebugLog("response JSON: " + jsonResponse)
    Return
End If

success = json.Load(jsonResponse)

//  Show the full JSON response.
json.EmitCompact = False
System.DebugLog(json.Emit())

//  A successful response looks like this:
//  {
//    "kind": "drive#file",
//    "id": "0B53Q6OSTWYoldmJ0Z3ZqT2x5MFk",
//    "name": "starfish.jpg",
//    "mimeType": "image/jpeg"
//  }

//  Get the fileId:
System.DebugLog("fileId: " + json.StringOf("id"))

The problem is in this part of the code:

Dim jpgBytes As New Chilkat.BinData
success = jpgBytes.LoadFile("qa_data/jpg/starfish.jpg")

I don't know how to load the path of the selected file since I don't know it (it must be a temporary path of the browser).

Update: (2021/08/31)

I have managed with javascript to upload a file directly to Google Drive but I don't know if the script could be adapted to work in Chilkat. What do you think about this, Matt?

Var s As String
Var id_folder As String = "1lwDHPYPFetdrDcwND2g07AsmCSWIUIbY" 

s = ""
s = s + "Var input_file = $('#formFileLg')[0].files[0];"
s = s + "Var formData = new FormData();"
s = s + "formData.append('formFileLg', input_file, input_file.name);"
s = s + "formData.append('upload_file', true);"
s = s + "var metadata = {"
s = s + "name: input_file.name,"
s = s + "mimeType: input_file.name.type,"
s = s + "parents: ['"+id_folder+"']"
s = s + "};"

s = s + "formData.append( 'metadata', new Blob( [JSON.stringify( metadata )], {type: 'application/json'} ));"
s = s + "$.ajax({"
s = s + "type: 'POST',"
s = s + "beforeSend: function(request) {"
s = s + "request.setRequestHeader('Authorization', 'Bearer' + ' ' + '"+API_TOKEN+"');"
s = s + "},"
s = s + "url: 'https://www.googleapis.com/upload/drive/v3/files?access_token="+API_TOKEN+"',"
s = s + "dataType: 'json',"
s = s + "data:{"
s = s + "uploadType:'media'},"
s = s + "xhr: function () {"
s = s + "var myXhr = $.ajaxSettings.xhr();"
s = s + "if (myXhr.upload) {"
s = s + "}"
s = s + "return myXhr;"
s = s + "},"
s = s + "success: function (data) {"
s = s + "console.log(data);"
s = s + "},"
s = s + "error: function (error) {"
s = s + "console.log(error);"
s = s + "},"
s = s + "async: true,"
s = s + "data: formData,"
s = s + "cache: false,"
s = s + "contentType: false,"
s = s + "processData: false,"
s = s + "timeout: 60000"
s = s + "});"

Me.ExecuteJavaScript(s)

I still don't know how to enter the temporary path of the selected file from the file chooser. In javascript I have used this code

s = s + "Var input_file = $('#formFileLg')[0].files[0];"

and it works but... what about in chilkat?

Could someone help me, please?.

Thank you very much.

Best regards,

Wardiam