(Delphi DLL) OneDrive -- List Large Directory

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 v9.5.0.68 or greater.

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, JsonObject, Http;

...

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

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

http := CkHttp_Create();

// Use your previously obtained access token here:
// See the following examples for getting an access token:
//    Get Microsoft Graph OAuth2 Access Token (Azure AD v2.0 Endpoint).
//    Get Microsoft Graph OAuth2 Access Token (Azure AD Endpoint).
//    Refresh Access Token (Azure AD v2.0 Endpoint).
//    Refresh Access Token (Azure AD Endpoint).

// (Make sure your token was obtained with the FilesRead or Files.ReadWrite scope.)
CkHttp_putAuthToken(http,'MICROSOFT_GRAPH_ACCESS_TOKEN');

// This example will get the DriveItems in /lots-of-files, which has 450 children..
CkHttp_SetUrlVar(http,'item_path','/lots-of-files');

json := CkJsonObject_Create();
CkJsonObject_putEmitCompact(json,False);

// This loop will download DriveItems in sets of 50 until no more exist.
bGetMore := True;
// (Add the $top query parameter to define the page size, i.e. the max number of results to return).
nextLink := 'https://graph.microsoft.com/v1.0/me/drive/root:{$item_path}:/children?$top=50';

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;

CkHttp_Dispose(http);
CkJsonObject_Dispose(json);

end;