Pascal (Lazarus/Delphi)

Page Through All Contacts

See more Google APIs Examples

Demonstrates how to page through the entire list of Google Contacts. 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;
  startIndex: Integer;
  maxResults: Integer;
  totalResults: Integer;
  sbMaxResults: TStringBuilder;
  sbStartIndex: TStringBuilder;
  loopIteration: Integer;
  sbResponseBody: TStringBuilder;
  xml: TXml;
  startIndex2: Integer;
  itemsPerPage: Integer;
  numEntries: Integer;
  i: Integer;
  idUrl: string;
  fullName: string;
  emailAddress: string;
  xLink: TXml;
  bHasPhoto: Boolean;

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..
  //  ----------------------------------------------

  startIndex := 1;
  maxResults := 25;
  //  The totalResults will get updated with the correct value in the 1st loop iteration..
  totalResults := 100;
  //  To retrieve the contacts in pages of 25 each, we need to send the following for each page.

  //  	GET /m8/feeds/contacts/default/full?max-results=25&start-index=<startIndex>
  //  	GData-Version: 3.0

  sbMaxResults := TStringBuilder.Create;
  sbMaxResults.AppendInt(maxResults);
  sbStartIndex := TStringBuilder.Create;

  loopIteration := 0;
  while startIndex <= totalResults do
    begin

      sbStartIndex.Clear();
      sbStartIndex.AppendInt(startIndex);

      rest.ClearAllHeaders();
      rest.ClearAllQueryParams();
      rest.AddHeader('GData-Version','3.0');
      rest.AddQueryParam('start-index',sbStartIndex.GetAsString());
      rest.AddQueryParam('max-results',sbMaxResults.GetAsString());

      sbResponseBody := TStringBuilder.Create;
      success := rest.FullRequestNoBodySb('GET','/m8/feeds/contacts/default/full',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);

      //  Now let's parse the XML...

      //  Get the the total number of results, the start index, and the items per page.
      //  We'll likely NOT get the full list, but will instead get the 1st page.
      totalResults := xml.GetChildIntValue('openSearch:totalResults');
      startIndex2 := xml.GetChildIntValue('openSearch:startIndex');
      itemsPerPage := xml.GetChildIntValue('openSearch:itemsPerPage');
      WriteLn('totalResults = ' + totalResults);
      WriteLn('startIndex = ' + startIndex2);
      WriteLn('itemsPerPage = ' + itemsPerPage);

      //  Iterate over each contact.
      numEntries := xml.NumChildrenHavingTag('entry');
      i := 0;
      while i < numEntries do
        begin
          xml.I := i;
          WriteLn(loopIteration * maxResults + i + 1 + ' ----');
          WriteLn('title: ' + xml.GetChildContent('entry[i]|title'));

          idUrl := xml.GetChildContent('entry[i]|id');
          WriteLn('id: ' + idUrl);

          fullName := xml.ChilkatPath('entry[i]|gd:name|gd:fullName|*');
          if (xml.LastMethodSuccess = True) then
            begin
              WriteLn('fullName: ' + fullName);
            end;

          emailAddress := xml.ChilkatPath('entry[i]|gd:email|(address)');
          if (xml.LastMethodSuccess = True) then
            begin
              WriteLn('email address: ' + emailAddress);
            end;

          //  Find the photo link and check to see if this contact has a photo.
          xLink := xml.GetChildWithAttr('link','rel','http://schemas.google.com/contacts/2008/rel#photo');
          if (xml.LastMethodSuccess = True) then
            begin
              //  Get the photo etag.
              bHasPhoto := xLink.HasAttribute('gd:etag');
              if (bHasPhoto = True) then
                begin
                  WriteLn('This contact has a photo.');
                end;
              xLink.Free;
            end;

          i := i + 1;
        end;

      startIndex := startIndex + maxResults;
      loopIteration := loopIteration + 1;
    end;



  jsonToken.Free;
  gAuth.Free;
  rest.Free;
  sbMaxResults.Free;
  sbStartIndex.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.