Pascal (Lazarus/Delphi)

OneDrive -- List Large Directory

See more OneDrive Examples

Demonstrates how to get the entire collection of DriveItem children when the collection is large and multiple pages need to be requested. To test this example, I created a DriveItem with 450 children.

Note: This example requires Chilkat v9.5.0.97 or greater.

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.JsonObject,
  Chilkat.Http;

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

procedure RunDemo;
var
  success: Boolean;
  json: TJsonObject;
  http: THttp;
  resp: string;
  i: Integer;
  numItems: Integer;
  bGetMore: Boolean;
  nextLink: string;

begin
  success := False;

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

  //  This example uses the OAuth client credentials flow.
  //  See How to Create an Azure App Registration for OAuth 2.0 Client Credentials

  //  Use your client ID, client secret, and tenant ID in the following lines
  json := TJsonObject.Create;
  json.UpdateString('client_id','2871da2c-8176-4b7f-869b-2311aa82e743');
  json.UpdateString('client_secret','2hu9Q~r5QuryUcEkNbg1btLtnfU1VUXzhSCG6brH');
  json.UpdateString('scope','https://graph.microsoft.com/.default');
  json.UpdateString('token_endpoint','https://login.microsoftonline.com/114d7ed6-71bf-4dbe-a866-748364121bf2/oauth2/v2.0/token');

  http := THttp.Create;
  http.AuthToken := json.Emit();

  //  This example will get the DriveItems in /lots-of-files, which has 450 children..
  http.SetUrlVar('item_path','/lots-of-files');
  http.SetUrlVar('user_id','4fe732c3-322e-4a6b-b729-2fd1eb5c6104');

  json.EmitCompact := False;

  //  This loop will download DriveItems in sets of 25 until no more exist.
  bGetMore := True;
  //  (Add the $top query parameter to define the page size, i.e. the max number of results to return).
  nextLink := 'https://graph.microsoft.com/v1.0/users/{$user_id}/drive/root:{$item_path}:/children?$top=25';

  while (bGetMore = True) do
    begin

      //  Get the next chunk of DriveItems
      resp := http.QuickGetStr(nextLink);
      if (http.LastMethodSuccess <> True) then
        begin
          WriteLn(http.LastErrorText);
          Exit;
        end;

      //  The response should be JSON.
      json.Load(resp);

      //  A successful response should return a status code of 200.
      if (http.LastStatus <> 200) then
        begin
          WriteLn(json.Emit());
          WriteLn('Response status = ' + http.LastStatus);
          Exit;
        end;

      //  Iterate over the DriveItems in the JSON response:
      i := 0;
      numItems := json.SizeOfArray('value');
      while i < numItems do
        begin
          json.I := i;
          WriteLn('name: ' + json.StringOf('value[i].name'));
          i := i + 1;
        end;

      //  If a nextLink was included in the JSON, use it to get the next set of 50 DriveItems.
      //  Otherwise, exit the loop.
      if (json.HasMember('"@odata.nextLink"') = True) then
        begin
          nextLink := json.StringOf('"@odata.nextLink"');
          WriteLn('nextLink: ' + nextLink);
        end
      else
        begin
          bGetMore := False;
        end;
    end;



  json.Free;
  http.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.