(Delphi DLL) Box.com Streaming Upload File

Demonstrates how to upload a file to box.com, streaming the file directly from the filesystem.

Note: This example requires a fix that is included in Chilkat v9.5.0.70 and above.

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, OAuth2, Rest, JsonObject, Stream;

...

procedure TForm1.Button1Click(Sender: TObject);
var
rest: HCkRest;
success: Boolean;
oauth2: HCkOAuth2;
bAutoReconnect: Boolean;
jsonAttr: HCkJsonObject;
fileStream: HCkStream;
responseBody: PWideChar;

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

rest := CkRest_Create();

//    Provide a previously obtained OAuth2 access token.
oauth2 := CkOAuth2_Create();
CkOAuth2_putAccessToken(oauth2,'BOX_ACCESS_TOKEN');
CkRest_SetAuthOAuth2(rest,oauth2);

//  First, make the initial connection.
//  A single REST object, once connected, can be used for many Box REST API calls.
//  The auto-reconnect indicates that if the already-established HTTPS connection is closed,
//  then it will be automatically re-established as needed.
bAutoReconnect := True;

//  ----------------------------------------------------------------------
//  IMPORTANT: Note that the domain is "upload.box.com", not "api.box.com"
//  ----------------------------------------------------------------------
success := CkRest_Connect(rest,'upload.box.com',443,True,bAutoReconnect);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

//  The request body uses the "multipart/form-data" format to transmit two "parts".
//  The first part is called "attributes" and contains a JSON object with information about the file, including the name of the file
//  and the ID of the parent folder. The second part contains the contents of the file.
//  (Note that the name of the second "part" is ignored.)

CkRest_AddHeader(rest,'Content-Type','multipart/form-data');

//  Provide the content for each part of the request...

//  First the JSON attributes.  Use "0" for the root folder.
//    {"name":"hedgehogs.jpg", "parent":{"id":"0"}}
jsonAttr := CkJsonObject_Create();
CkJsonObject_UpdateString(jsonAttr,'name','hedgehogs.jpg');
CkJsonObject_UpdateString(jsonAttr,'parent.id','0');

CkRest_putPartSelector(rest,'1');
CkRest_AddHeader(rest,'Content-Disposition','form-data; name="attributes"; ');
CkRest_SetMultipartBodyString(rest,CkJsonObject__emit(jsonAttr));

//  The upload will stream directly from a file.
CkRest_putPartSelector(rest,'2');
CkRest_AddHeader(rest,'Content-Disposition','form-data; name="file"; filename="hedgehogs.jpg"');
//  "application/octet-stream" can be safely used for any type file..
CkRest_AddHeader(rest,'Content-Type','application/octet-stream');

//  IMPORTANT: This example requires Chilkat v9.5.0.70 or later, for a fix that was made in
//  multipart/streaming uploads.
fileStream := CkStream_Create();
CkStream_putSourceFile(fileStream,'qa_data/jpg/hedgehogs.jpg');
CkRest_SetMultipartBodyStream(rest,fileStream);

//  Restore the PartSelector to "0" (for safety, in case something else sends another request on this object)
CkRest_putPartSelector(rest,'0');

//  Send the multipart/form-data request, which uploads the file by streaming directly from the filesystem.
responseBody := CkRest__fullRequestMultipart(rest,'POST','/api/2.0/files/content');
if (CkRest_getLastMethodSuccess(rest) <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

//  A 201 is received for a successful upload
if (CkRest_getResponseStatusCode(rest) <> 201) then
  begin
    Memo1.Lines.Add('Box.com upload failed.');
    Memo1.Lines.Add('Request header:');
    Memo1.Lines.Add(CkRest__lastRequestHeader(rest));
    Memo1.Lines.Add('---');
    Memo1.Lines.Add('Response status code = ' + IntToStr(CkRest_getResponseStatusCode(rest)));
    Memo1.Lines.Add('Response body:');
    Memo1.Lines.Add(responseBody);
    Exit;
  end;

Memo1.Lines.Add('File uploaded.');

CkRest_Dispose(rest);
CkOAuth2_Dispose(oauth2);
CkJsonObject_Dispose(jsonAttr);
CkStream_Dispose(fileStream);

end;