Delphi DLL

Google Contacts - Delete a Contact

See more Google APIs Examples

Demonstrates how to delete a Google Contact. Delphi DLL

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, StringBuilder, AuthGoogle, Xml, JsonObject, Rest;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
jsonToken: HCkJsonObject;
gAuth: HCkAuthGoogle;
rest: HCkRest;
bAutoReconnect: Boolean;
sbPath: HCkStringBuilder;
numReplacements: Integer;
sbResponseBody: HCkStringBuilder;
xml: HCkXml;
lastKnownEtag: PWideChar;

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 := CkJsonObject_Create();
success := CkJsonObject_LoadFile(jsonToken,'qa_data/tokens/googleContacts.json');
if (success <> True) then
  begin
    Memo1.Lines.Add('Failed to load googleContacts.json');
    Exit;
  end;

gAuth := CkAuthGoogle_Create();
CkAuthGoogle_putAccessToken(gAuth,CkJsonObject__stringOf(jsonToken,'access_token'));

rest := CkRest_Create();

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

// Provide the authentication credentials (i.e. the access token)
CkRest_SetAuthGoogle(rest,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

CkRest_AddHeader(rest,'GData-Version','3.0');

sbPath := CkStringBuilder_Create();
CkStringBuilder_Append(sbPath,'/m8/feeds/contacts/default/full/{contactId}');
// Get the contact having contactId = "5b6d64980b1ed462"
numReplacements := CkStringBuilder_Replace(sbPath,'{contactId}','5b6d64980b1ed462');

sbResponseBody := CkStringBuilder_Create();
success := CkRest_FullRequestNoBodySb(rest,'GET',CkStringBuilder__getAsString(sbPath),sbResponseBody);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

// A successful response will have a status code equal to 200.
if (CkRest_getResponseStatusCode(rest) <> 200) then
  begin
    Memo1.Lines.Add('response status code = ' + IntToStr(CkRest_getResponseStatusCode(rest)));
    Memo1.Lines.Add('response status text = ' + CkRest__responseStatusText(rest));
    Memo1.Lines.Add('response header: ' + CkRest__responseHeader(rest));
    Memo1.Lines.Add('response body: ' + CkStringBuilder__getAsString(sbResponseBody));
    Exit;
  end;

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

Memo1.Lines.Add(CkXml__getXml(xml));
Memo1.Lines.Add('-------------------');

// Get the etag:
lastKnownEtag := CkXml__getAttrValue(xml,'gd:etag');
Memo1.Lines.Add('lastKnownEtag = ' + lastKnownEtag);
Memo1.Lines.Add('-------------------');

// To delete, send the following:

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

CkRest_ClearAllHeaders(rest);
CkRest_AddHeader(rest,'If-Match',lastKnownEtag);
CkRest_AddHeader(rest,'GData-Version','3.0');

// The sbPath already contains the correct path..
success := CkRest_FullRequestNoBodySb(rest,'DELETE',CkStringBuilder__getAsString(sbPath),sbResponseBody);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

// A successful response will have a status code equal to 200.
if (CkRest_getResponseStatusCode(rest) <> 200) then
  begin
    Memo1.Lines.Add('response status code = ' + IntToStr(CkRest_getResponseStatusCode(rest)));
    Memo1.Lines.Add('response status text = ' + CkRest__responseStatusText(rest));
    Memo1.Lines.Add('response header: ' + CkRest__responseHeader(rest));
    Memo1.Lines.Add('response body: ' + CkStringBuilder__getAsString(sbResponseBody));
    Memo1.Lines.Add('request header: ' + CkRest__lastRequestHeader(rest));
    Exit;
  end;

// The response body for a successful DELETE is empty.
Memo1.Lines.Add('Response Body: (should be empty)');
Memo1.Lines.Add(CkStringBuilder__getAsString(sbResponseBody));
Memo1.Lines.Add('Success.');

CkJsonObject_Dispose(jsonToken);
CkAuthGoogle_Dispose(gAuth);
CkRest_Dispose(rest);
CkStringBuilder_Dispose(sbPath);
CkStringBuilder_Dispose(sbResponseBody);
CkXml_Dispose(xml);

end;