Pascal (Lazarus/Delphi)

Firebase DELETE - Removing Data

See more Firebase Examples

Uses the DELETE method to delete data. The data used in this example is at Chilkat Firebase Pigs Database, and is shown here:

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.FileAccess,
  Chilkat.Rest,
  Chilkat.AuthGoogle;

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

procedure RunDemo;
var
  success: Boolean;
  fac: TFileAccess;
  accessToken: string;
  rest: TRest;
  authGoogle: TAuthGoogle;
  jsonResponse: string;

begin
  success := False;

  //  Uses the DELETE method to delete a Firebase record.

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

  //  This example assumes a JWT authentication token, if required, has been previously obtained.
  //  See Get Firebase Access Token from JSON Service Account Private Key for sample code.

  //  Load the previously obtained Firebase access token into a string.
  fac := TFileAccess.Create;
  accessToken := fac.ReadEntireTextFile('qa_data/tokens/firebaseToken.txt','utf-8');
  if (fac.LastMethodSuccess <> True) then
    begin
      WriteLn(fac.LastErrorText);
      Exit;
    end;

  rest := TRest.Create;

  //  Make the initial connection (without sending a request yet).
  //  Once connected, any number of requests may be sent.  It is not necessary to explicitly
  //  call Connect before each request.  
  success := rest.Connect('chilkat.firebaseio.com',443,True,True);
  if (success <> True) then
    begin
      WriteLn(rest.LastErrorText);
      Exit;
    end;
  authGoogle := TAuthGoogle.Create;
  authGoogle.AccessToken := accessToken;
  rest.SetAuthGoogle(authGoogle);

  //  Chilkat's sample data (pig-rescue data) is publicly readable at: https://chilkat.firebaseio.com/.json
  //  This data is publicly readable, but not writable.  You'll need to 
  //  run against your own database..

  //  We're going to delete a pig we previously added.  The push ID of that pig was -KI3pT33wKauiMxY4QTB,
  //  so the path will be "/pig-rescue/animal/-KI3pT33wKauiMxY4QTB.json"

  jsonResponse := rest.FullRequestNoBody('DELETE','/pig-rescue/animal/-KI3pT33wKauiMxY4QTB.json');
  if (rest.LastMethodSuccess <> True) then
    begin
      //  Something happened in the communications (either no request was sent, or no response was received.
      //  (The Chilkat REST API also has lower-level methods where an app can send the request in one call,
      //  and then receive the response in another call.)
      WriteLn(rest.LastErrorText);
      Exit;
    end;

  //  Check the response status code.   A 200 response status indicates success.
  if (rest.ResponseStatusCode <> 200) then
    begin
      WriteLn(rest.ResponseStatusText);
      WriteLn(jsonResponse);
      WriteLn('Failed.');
      Exit;
    end;

  WriteLn('Success.');


  fac.Free;
  rest.Free;
  authGoogle.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.