Pascal (Lazarus/Delphi)

Google Contacts - Delete a Contact

See more Google APIs Examples

Demonstrates how to delete a Google Contact. 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.StringBuilder,
  Chilkat.AuthGoogle,
  Chilkat.Xml,
  Chilkat.JsonObject,
  Chilkat.Rest;

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

procedure RunDemo;
var
  success: Boolean;
  jsonToken: TJsonObject;
  gAuth: TAuthGoogle;
  rest: TRest;
  bAutoReconnect: Boolean;
  sbPath: TStringBuilder;
  numReplacements: Integer;
  sbResponseBody: TStringBuilder;
  xml: TXml;
  lastKnownEtag: string;

begin
  success := False;

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

  //  --------------------------------------------------------------------------------------------------------
  //  Note: The code for setting up the Chilkat REST object and making the initial connection can be done once.
  //  Once connected, the REST object may be re-used for many REST API calls.
  //  (It's a good idea to put the connection setup code in a separate function/subroutine.)
  //  --------------------------------------------------------------------------------------------------------

  //  It is assumed we previously obtained an OAuth2 access token.
  //  This example loads the JSON access token file 
  //  saved by this example: Get Google Contacts OAuth2 Access Token

  jsonToken := TJsonObject.Create;
  success := jsonToken.LoadFile('qa_data/tokens/googleContacts.json');
  if (success <> True) then
    begin
      WriteLn('Failed to load googleContacts.json');
      Exit;
    end;

  gAuth := TAuthGoogle.Create;
  gAuth.AccessToken := jsonToken.StringOf('access_token');

  rest := TRest.Create;

  //  Connect using TLS.
  bAutoReconnect := True;
  success := rest.Connect('www.google.com',443,True,bAutoReconnect);

  //  Provide the authentication credentials (i.e. the access token)
  rest.SetAuthGoogle(gAuth);

  //  ----------------------------------------------
  //  OK, the REST connection setup is completed..
  //  ----------------------------------------------

  //  To update a contact, we'll first get the contact information
  //  to get the etag.

  //  To retrieve the contact, send the following:
  //  	GET /m8/feeds/contacts/default/full/{contactId}
  //  	GData-Version: 3.0

  rest.AddHeader('GData-Version','3.0');

  sbPath := TStringBuilder.Create;
  sbPath.Append('/m8/feeds/contacts/default/full/{contactId}');
  //  Get the contact having contactId = "5b6d64980b1ed462"
  numReplacements := sbPath.Replace('{contactId}','5b6d64980b1ed462');

  sbResponseBody := TStringBuilder.Create;
  success := rest.FullRequestNoBodySb('GET',sbPath.GetAsString(),sbResponseBody);
  if (success <> True) then
    begin
      WriteLn(rest.LastErrorText);
      Exit;
    end;

  //  A successful response will have a status code equal to 200.
  if (rest.ResponseStatusCode <> 200) then
    begin
      WriteLn('response status code = ' + rest.ResponseStatusCode);
      WriteLn('response status text = ' + rest.ResponseStatusText);
      WriteLn('response header: ' + rest.ResponseHeader);
      WriteLn('response body: ' + sbResponseBody.GetAsString());
      Exit;
    end;

  //  If the 200 response was received, then the contacts XML is contained
  //  in the response body.
  xml := TXml.Create;
  xml.LoadSb(sbResponseBody,False);

  WriteLn(xml.GetXml());
  WriteLn('-------------------');

  //  Get the etag:
  lastKnownEtag := xml.GetAttrValue('gd:etag');
  WriteLn('lastKnownEtag = ' + lastKnownEtag);
  WriteLn('-------------------');

  //  To delete, send the following:

  //  	DELETE /m8/feeds/contacts/default/full/{contactId}
  //  	If-Match: {lastKnownEtag}
  //  	GData-Version: 3.0

  rest.ClearAllHeaders();
  rest.AddHeader('If-Match',lastKnownEtag);
  rest.AddHeader('GData-Version','3.0');

  //  The sbPath already contains the correct path..
  success := rest.FullRequestNoBodySb('DELETE',sbPath.GetAsString(),sbResponseBody);
  if (success <> True) then
    begin
      WriteLn(rest.LastErrorText);
      Exit;
    end;

  //  A successful response will have a status code equal to 200.
  if (rest.ResponseStatusCode <> 200) then
    begin
      WriteLn('response status code = ' + rest.ResponseStatusCode);
      WriteLn('response status text = ' + rest.ResponseStatusText);
      WriteLn('response header: ' + rest.ResponseHeader);
      WriteLn('response body: ' + sbResponseBody.GetAsString());
      WriteLn('request header: ' + rest.LastRequestHeader);
      Exit;
    end;

  //  The response body for a successful DELETE is empty.
  WriteLn('Response Body: (should be empty)');
  WriteLn(sbResponseBody.GetAsString());
  WriteLn('Success.');


  jsonToken.Free;
  gAuth.Free;
  rest.Free;
  sbPath.Free;
  sbResponseBody.Free;
  xml.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.