Delphi DLL

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.

Delphi DLL

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
json: HCkJsonObject;
http: HCkHttp;
resp: PWideChar;
i: Integer;
numItems: Integer;
bGetMore: Boolean;
nextLink: PWideChar;

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 := CkJsonObject_Create();
CkJsonObject_UpdateString(json,'client_id','2871da2c-8176-4b7f-869b-2311aa82e743');
CkJsonObject_UpdateString(json,'client_secret','2hu9Q~r5QuryUcEkNbg1btLtnfU1VUXzhSCG6brH');
CkJsonObject_UpdateString(json,'scope','https://graph.microsoft.com/.default');
CkJsonObject_UpdateString(json,'token_endpoint','https://login.microsoftonline.com/114d7ed6-71bf-4dbe-a866-748364121bf2/oauth2/v2.0/token');

http := CkHttp_Create();
CkHttp_putAuthToken(http,CkJsonObject__emit(json));

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

CkJsonObject_putEmitCompact(json,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 := CkHttp__quickGetStr(http,nextLink);
    if (CkHttp_getLastMethodSuccess(http) <> True) then
      begin
        Memo1.Lines.Add(CkHttp__lastErrorText(http));
        Exit;
      end;

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

    // A successful response should return a status code of 200.
    if (CkHttp_getLastStatus(http) <> 200) then
      begin
        Memo1.Lines.Add(CkJsonObject__emit(json));
        Memo1.Lines.Add('Response status = ' + IntToStr(CkHttp_getLastStatus(http)));
        Exit;
      end;

    // Iterate over the DriveItems in the JSON response:
    i := 0;
    numItems := CkJsonObject_SizeOfArray(json,'value');
    while i < numItems do
      begin
        CkJsonObject_putI(json,i);
        Memo1.Lines.Add('name: ' + CkJsonObject__stringOf(json,'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 (CkJsonObject_HasMember(json,'"@odata.nextLink"') = True) then
      begin
        nextLink := CkJsonObject__stringOf(json,'"@odata.nextLink"');
        Memo1.Lines.Add('nextLink: ' + nextLink);
      end
    else
      begin
        bGetMore := False;
      end;
  end;

CkJsonObject_Dispose(json);
CkHttp_Dispose(http);

end;