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

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Url, HttpResponse, HttpRequest, JsonObject, StringBuilder, Http;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
http: HCkHttp;
json: HCkJsonObject;
resp: HCkHttpResponse;
statusCode: Integer;
sbSessionUri: HCkStringBuilder;
sessionUri: PWideChar;
req: HCkHttpRequest;
url: HCkUrl;

begin
// 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

http := CkHttp_Create();

CkHttp_putAuthToken(http,'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"
// }

CkHttp_SetRequestHeader(http,'X-Upload-Content-Type','application/zip');
CkHttp_SetRequestHeader(http,'X-Upload-Content-Length','1366807');

json := CkJsonObject_Create();
CkJsonObject_UpdateString(json,'name','myZip');

resp := CkHttp_PostJson3(http,'https://www.googleapis.com/upload/drive/v3/files?uploadType=resumable','application/json',json);
if (CkHttp_getLastMethodSuccess(http) = False) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

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

// The session URI is in the "Location" response header:
sbSessionUri := CkStringBuilder_Create();
CkStringBuilder_Append(sbSessionUri,CkHttpResponse__getHeaderField(resp,'Location'));
sessionUri := CkStringBuilder__getAsString(sbSessionUri);
Memo1.Lines.Add('Session URI: ' + sessionUri);

CkHttpResponse_Dispose(resp);

// 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.
CkHttp_ClearHeaders(http);

// 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 := CkHttpRequest_Create();

CkHttpRequest_putContentType(req,'application/zip');
CkHttpRequest_putHttpVerb(req,'PUT');

url := CkUrl_Create();
CkUrl_ParseUrl(url,sessionUri);

CkHttpRequest_putPath(req,CkUrl__pathWithQueryParams(url));
Memo1.Lines.Add('Path with Query Param: ' + CkUrl__pathWithQueryParams(url));

// Specify that the request body is to be streamed directly from a file.
success := CkHttpRequest_StreamBodyFromFile(req,'qa_data/zips/big.zip');
if (success = False) then
  begin
    Memo1.Lines.Add(CkHttpRequest__lastErrorText(req));
    Exit;
  end;

resp := CkHttp_SynchronousRequest(http,CkUrl__host(url),CkUrl_getPort(url),CkUrl_getSsl(url),req);
if (CkHttp_getLastMethodSuccess(http) = False) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

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

// Sample output:

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

CkHttpResponse_Dispose(resp);

CkHttp_Dispose(http);
CkJsonObject_Dispose(json);
CkStringBuilder_Dispose(sbSessionUri);
CkHttpRequest_Dispose(req);
CkUrl_Dispose(url);

end;