(Delphi DLL) Paging User Photos with Cursor

Demonstrates how to iterate over the pages of user photos using a cursor.

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, OAuth2, Rest, JsonObject;

...

procedure TForm1.Button1Click(Sender: TObject);
var
oauth2: HCkOAuth2;
rest: HCkRest;
success: Boolean;
responseJson: PWideChar;
json: HCkJsonObject;
afterCursor: PWideChar;

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

// This example assumes a previously obtained an access token
oauth2 := CkOAuth2_Create();
CkOAuth2_putAccessToken(oauth2,'FACEBOOK-ACCESS-TOKEN');

rest := CkRest_Create();

// Connect to Facebook.
success := CkRest_Connect(rest,'graph.facebook.com',443,True,True);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

// Provide the authentication credentials (i.e. the access key)
CkRest_SetAuthOAuth2(rest,oauth2);

// Indicate that we only want the photos the user has personally uploaded.
CkRest_AddQueryParam(rest,'type','uploaded');

// We could limit the number of photos per page using the "limit" field.
CkRest_AddQueryParam(rest,'limit','20');

// Get the 1st page of photos. (Not the actual image data, but the information about each photo.)
// See https://developers.facebook.com/docs/graph-api/reference/user/photos/ for more information.
responseJson := CkRest__fullRequestNoBody(rest,'GET','/v2.7/me/photos');
if (CkRest_getLastMethodSuccess(rest) <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

json := CkJsonObject_Create();
CkJsonObject_putEmitCompact(json,False);
CkJsonObject_Load(json,responseJson);
Memo1.Lines.Add(CkJsonObject__emit(json));

// 
// See Parsing the Facebook User Photos for code showing how to parse the JSON photos content.
// 

// Get the "after" cursor.
afterCursor := CkJsonObject__stringOf(json,'paging.cursors.after');
while CkJsonObject_getLastMethodSuccess(json) = True do
  begin

    Memo1.Lines.Add('after cursor: ' + afterCursor);

    // Prepare for getting the next page of photos.
    // We can continue using the same REST object.
    // If already connected, we'll continue using the existing connection.
    // Otherwise, a new connection will automatically be made if needed.
    CkRest_ClearAllQueryParams(rest);
    CkRest_AddQueryParam(rest,'type','uploaded');
    CkRest_AddQueryParam(rest,'limit','20');
    CkRest_AddQueryParam(rest,'after',afterCursor);

    responseJson := CkRest__fullRequestNoBody(rest,'GET','/v2.7/me/photos');
    if (CkRest_getLastMethodSuccess(rest) <> True) then
      begin
        Memo1.Lines.Add(CkRest__lastErrorText(rest));
        Exit;
      end;

    CkJsonObject_Load(json,responseJson);
    // See Parsing the Facebook User Photos for code showing how to parse the JSON photos content.

    Memo1.Lines.Add(CkJsonObject__emit(json));

    // Get the cursor for the next page.
    afterCursor := CkJsonObject__stringOf(json,'paging.cursors.after');
  end;

Memo1.Lines.Add('No more pages of photos.');

CkOAuth2_Dispose(oauth2);
CkRest_Dispose(rest);
CkJsonObject_Dispose(json);

end;