B4X Requires Chilkat v11.0.0+
Google Drive - Resumable Upload

Demonstrates how to do a resumable upload to Google Drive.
Chilkat B4X Downloads

B4X
Dim success As Boolean = False

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

success = True

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

Dim http As ChilkatHttp
http.Initialize("http")

http.AuthToken = "GOOGLE_DRIVE_ACCESS_TOKEN"

'  First we want to initiate the resumable upload.
'  We send a POST to get a session URI, which will be used to upload the file, and resume if needed.

'  Our POST will look like this:

'  POST https://www.googleapis.com/upload/drive/v3/files?uploadType=resumable HTTP/1.1
'  Authorization: Bearer [YOUR_AUTH_TOKEN]          <-- Chilkat automatically adds this header because the AuthToken property was set.
'  Content-Length: 38                               <-- Chilkat will automatically add this header.
'  Content-Type: application/json; charset=UTF-8    <-- This is the type of this POST, and is specified in the call to HttpJson.
'  X-Upload-Content-Type: application/zip           <-- The type of file we'll be uploading
'  X-Upload-Content-Length: 1366807                 <-- The size of the file we'll be uploading
'  
'  {
'    "name": "myObject"
'  }

http.SetRequestHeader("X-Upload-Content-Type", "application/zip")
http.SetRequestHeader("X-Upload-Content-Length", "1366807")

Dim json As ChilkatJsonObject
json.Initialize
json.UpdateString("name", "myZip")

Dim resp As ChilkatHttpResponse
resp.Initialize
success = http.HttpJson("POST", "https://www.googleapis.com/upload/drive/v3/files?uploadType=resumable", json, "application/json", resp)
If success = False Then
    Log(http.LastErrorText)
    Return
End If


Dim statusCode As Int = resp.StatusCode
If statusCode <> 200 Then
    Log(resp.BodyStr)
    Log("response status = " & statusCode)
    Return
End If


'  The session URI is in the "Location" response header:
Dim sbSessionUri As ChilkatStringBuilder
sbSessionUri.Initialize
sbSessionUri.Append(resp.GetHeaderField("Location"))
Dim sessionUri As String = sbSessionUri.GetAsString
Log("Session URI: " & sessionUri)

'  Here's a sample session URI:  https://www.googleapis.com/upload/drive/v3/files?uploadType=resumable&upload_id=AEnB2UrszR8lDqlo3mtXJw_0rYI_Hi1oVh1NPFcLfoyBq9NcSjk85kFopoZaVEgT38OSmLl0XsObPf4iCSJwHlrOvvIJQ_ckIQ

'  -----------------------------------------------------------------------------
'  The next step is to upload the file using the session URI:

'  We'll send a PUT that looks like this:

'  PUT https://www.googleapis.com/upload/drive/v3/files?uploadType=resumable&upload_id=xa298sd_sdlkj2 HTTP/1.1
'  Content-Length: 1366807
'  Content-Type: application/zip
'  
'  [BYTES 0-1366806]

'  First remove the X-Upload-Content-Type and X-Upload-Content-Length request headers we specified earlier, so they don't get sent with subsequent requests.
http.ClearHeaders

'  Because the file is likely large, we'll use HttpSReq which allows to to pass an HTTP request object where the body can be streamed directly from a file.
Dim req As ChilkatHttpRequest
req.Initialize

req.ContentType = "application/zip"
req.HttpVerb = "PUT"

Dim url As ChilkatUrl
url.Initialize
url.ParseUrl(sessionUri)

req.Path = url.PathWithQueryParams
Log("Path with Query Param: " & url.PathWithQueryParams)

'  Specify that the request body is to be streamed directly from a file.
success = req.StreamBodyFromFile("qa_data/zips/big.zip")
If success = False Then
    Log(req.LastErrorText)
    Return
End If


success = http.HttpSReq(url.Host, url.Port, url.Ssl, req, resp)
If success = False Then
    Log(http.LastErrorText)
    Return
End If


Log(resp.BodyStr)
Log("response status = " & resp.StatusCode)

'  Sample output:

'  {
'   "kind": "drive#file",
'   "id": "1rx20i53eurtkVQ-RT7Ry8Ct85PgPYMET",
'   "name": "myZip",
'   "mimeType": "application/zip"
'  }
'  
'  response status = 200