(Delphi ActiveX) Google Drive - Resumable Upload

Demonstrates how to do a resumable upload to Google Drive.

For more information, see https://developers.google.com/drive/api/v3/manage-uploads#resumable

Chilkat for Delphi Downloads Chilkat ActiveX DLL for Delphi Chilkat non-ActiveX DLL for Delphi * The examples here use the ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Integer;
http: TChilkatHttp;
json: TChilkatJsonObject;
resp: IChilkatHttpResponse;
statusCode: Integer;
sbSessionUri: TChilkatStringBuilder;
sessionUri: WideString;
req: TChilkatHttpRequest;
url: TChilkatUrl;

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

success := 1;

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

http := TChilkatHttp.Create(Self);

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 PostJson3.
// 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');

json := TChilkatJsonObject.Create(Self);
json.UpdateString('name','myZip');

resp := http.PostJson3('https://www.googleapis.com/upload/drive/v3/files?uploadType=resumable','application/json',json.ControlInterface);
if (http.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(http.LastErrorText);
    Exit;
  end;

statusCode := resp.StatusCode;
if (statusCode <> 200) then
  begin
    Memo1.Lines.Add(resp.BodyStr);
    Memo1.Lines.Add('response status = ' + IntToStr(statusCode));
    Exit;
  end;

// The session URI is in the "Location" response header:
sbSessionUri := TChilkatStringBuilder.Create(Self);
sbSessionUri.Append(resp.GetHeaderField('Location'));
sessionUri := sbSessionUri.GetAsString();
Memo1.Lines.Add('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 SynchronousRequest which allows to to pass an HTTP request object where the body can be streamed directly from a file.
req := TChilkatHttpRequest.Create(Self);

req.ContentType := 'application/zip';
req.HttpVerb := 'PUT';

url := TChilkatUrl.Create(Self);
url.ParseUrl(sessionUri);

req.Path := url.PathWithQueryParams;
Memo1.Lines.Add('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 = 0) then
  begin
    Memo1.Lines.Add(req.LastErrorText);
    Exit;
  end;

resp := http.SynchronousRequest(url.Host,url.Port,url.Ssl,req.ControlInterface);
if (http.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(http.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add(resp.BodyStr);
Memo1.Lines.Add('response status = ' + IntToStr(statusCode));

// Sample output:

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