Pascal (Lazarus/Delphi)

Download File from Dropbox into a String Variable

See more Dropbox Examples

Demonstrates how to download a file from Dropbox directly into a string variable. Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Rest,
  Chilkat.DtObj,
  Chilkat.JsonObject,
  Chilkat.CkDateTime;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  rest: TRest;
  json: TJsonObject;
  fileContent: string;
  apiResult: string;
  jsonResult: TJsonObject;
  size: Integer;
  rev: string;
  clientModified: string;
  ckdt: TCkDateTime;
  bLocalTime: Boolean;
  dt: TDtObj;

begin
  success := False;

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

  //  A Dropbox access token should have been previously obtained.
  //  Dropbox access tokens do not expire.
  //  See Dropbox Access Token.

  rest := TRest.Create;

  //  Connect to Dropbox
  success := rest.Connect('content.dropboxapi.com',443,True,True);
  if (success = False) then
    begin
      WriteLn(rest.LastErrorText);
      Exit;
    end;

  //  Add request headers.
  rest.AddHeader('Authorization','Bearer DROPBOX_ACCESS_TOKEN');

  //  The download "parameters" are contained in JSON passed in an HTTP request header.
  //  This is the JSON indicating the file to be downloaded:
  //  { 
  //     "path": "/jack.txt",
  //  }

  json := TJsonObject.Create;
  json.AppendString('path','/jack.txt');
  rest.AddHeader('Dropbox-API-Arg',json.Emit());

  //  The content of the file on Dropbox is returned.
  fileContent := rest.FullRequestNoBody('POST','/2/files/download');
  if (rest.LastMethodSuccess = False) then
    begin
      WriteLn(rest.LastErrorText);
      Exit;
    end;

  //  When successful, Dropbox responds with a 200 response code.
  if (rest.ResponseStatusCode <> 200) then
    begin
      //  Examine the request/response to see what happened.
      WriteLn('response status code = ' + rest.ResponseStatusCode);
      WriteLn('response status text = ' + rest.ResponseStatusText);
      WriteLn('response header: ' + rest.ResponseHeader);
      WriteLn('response body (if any): ' + fileContent);
      WriteLn('---');
      WriteLn('LastRequestStartLine: ' + rest.LastRequestStartLine);
      WriteLn('LastRequestHeader: ' + rest.LastRequestHeader);
      Exit;
    end;

  //  Show the file content that was downloaded:
  WriteLn(fileContent);
  WriteLn('----');

  //  Information about the downloaded file is also available as JSON in a response header.
  //  The "dropbox-api-result" response header contains the information.  For example:
  apiResult := rest.ResponseHdrByName('dropbox-api-result');
  WriteLn(apiResult);

  //  In this case, the pretty-formatted dropbox-api-result JSON looks like this:
  //  { 
  //    "name": "jack.txt",
  //    "path_lower": "/jack.txt",
  //    "path_display": "/jack.txt",
  //    "id": "id:yqx4-tE_NKAAAAAAAAAAAQ",
  //    "client_modified": "2016-06-02T20:42:11Z",
  //    "server_modified": "2016-06-02T20:42:11Z",
  //    "rev": "8482db15f",
  //    "size": 42
  //  }

  //  Load the JSON, pretty-print it, and demonstrate how to get some values...
  jsonResult := TJsonObject.Create;
  jsonResult.EmitCompact := False;
  jsonResult.Load(apiResult);
  //  Show the JSON pretty-printed...
  WriteLn(jsonResult.Emit());

  //  Sample code to get data from the JSON response:
  size := jsonResult.IntOf('size');
  WriteLn('size = ' + size);

  rev := jsonResult.StringOf('rev');
  WriteLn('rev = ' + rev);

  clientModified := jsonResult.StringOf('client_modified');
  ckdt := TCkDateTime.Create;
  ckdt.SetFromTimestamp(clientModified);
  bLocalTime := True;
  dt := TDtObj.Create;
  ckdt.ToDtObj(bLocalTime,dt);

  WriteLn(dt.Day + '/' + dt.Month + '/' + dt.Year + ' ' + dt.Hour + ':' + dt.Minute);


  rest.Free;
  json.Free;
  jsonResult.Free;
  ckdt.Free;
  dt.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.