(Delphi ActiveX) 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 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
rest: TChilkatRest;
success: Integer;
oauth2: TChilkatOAuth2;
bAutoReconnect: Integer;
jsonAttr: TChilkatJsonObject;
fileStream: TChilkatStream;
responseBody: WideString;

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

rest := TChilkatRest.Create(Self);

//   Provide a previously obtained OAuth2 access token.
oauth2 := TChilkatOAuth2.Create(Self);
oauth2.AccessToken := 'BOX_ACCESS_TOKEN';
rest.SetAuthOAuth2(oauth2.ControlInterface);

// 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 := 1;

// ----------------------------------------------------------------------
// IMPORTANT: Note that the domain is "upload.box.com", not "api.box.com"
// ----------------------------------------------------------------------
success := rest.Connect('upload.box.com',443,1,bAutoReconnect);
if (success <> 1) then
  begin
    Memo1.Lines.Add(rest.LastErrorText);
    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.)

rest.AddHeader('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 := TChilkatJsonObject.Create(Self);
jsonAttr.UpdateString('name','hedgehogs.jpg');
jsonAttr.UpdateString('parent.id','0');

rest.PartSelector := '1';
rest.AddHeader('Content-Disposition','form-data; name="attributes"; ');
rest.SetMultipartBodyString(jsonAttr.Emit());

// The upload will stream directly from a file.
rest.PartSelector := '2';
rest.AddHeader('Content-Disposition','form-data; name="file"; filename="hedgehogs.jpg"');
// "application/octet-stream" can be safely used for any type file..
rest.AddHeader('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 := TChilkatStream.Create(Self);
fileStream.SourceFile := 'qa_data/jpg/hedgehogs.jpg';
rest.SetMultipartBodyStream(fileStream.ControlInterface);

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

// Send the multipart/form-data request, which uploads the file by streaming directly from the filesystem.
responseBody := rest.FullRequestMultipart('POST','/api/2.0/files/content');
if (rest.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(rest.LastErrorText);
    Exit;
  end;

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

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