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Pascal (Lazarus/Delphi)

Google Contacts - Retrieve as JSON

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Demonstrates how to retrieve Google Contacts as JSON.

Chilkat Pascal (Lazarus/Delphi) Downloads

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.JsonObject,
  Chilkat.Rest;

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

procedure RunDemo;
var
  success: Boolean;
  jsonToken: TJsonObject;
  gAuth: TAuthGoogle;
  rest: TRest;
  bAutoReconnect: Boolean;
  sbResponseBody: TStringBuilder;
  json: TJsonObject;
  totalResults: Integer;
  startIndex: Integer;
  itemsPerPage: Integer;
  numEntries: Integer;
  i: Integer;
  fullName: string;
  numEmailAddresses: Integer;
  j: Integer;
  emailAddress: 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 retrieve the contacts, we need to send the following:

  //  	GET /m8/feeds/contacts/default/full
  //  	GData-Version: 3.0

  //  To get the contacts data in JSON format, set the "alt" query parameter to "json"
  rest.AddQueryParam('alt','json');
  rest.AddHeader('GData-Version','3.0');

  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 JSON is contained
  //  in the response body.
  json := TJsonObject.Create;
  json.LoadSb(sbResponseBody);
  json.EmitCompact := False;

  //  Save the pretty-printed JSON response to a file.
  sbResponseBody.Clear();
  json.EmitSb(sbResponseBody);
  sbResponseBody.WriteFile('qa_output/google_contacts.json','utf-8',False);

  //  Parse the Google Contacts JSON, and iterate over the contacts..
  totalResults := json.IntOf('feed.openSearch$totalResults.$t');
  startIndex := json.IntOf('feed.openSearch$startIndex.$t');
  itemsPerPage := json.IntOf('feed.openSearch$itemsPerPage.$t');
  WriteLn('totalResults = ' + totalResults);
  WriteLn('startIndex = ' + startIndex);
  WriteLn('itemsPerPage = ' + itemsPerPage);

  numEntries := json.SizeOfArray('feed.entry');
  i := 0;
  while i < numEntries do
    begin
      json.I := i;
      WriteLn(i + 1 + ' ----');
      WriteLn('title: ' + json.StringOf('feed.entry[i].title.$t'));

      fullName := json.StringOf('feed.entry[i].gd$name.gd$fullName.$t');
      if (json.LastMethodSuccess = True) then
        begin
          WriteLn('fullName: ' + fullName);
        end;

      //  There can be multiple email addresses, so it's stored as a JSON array..
      numEmailAddresses := json.SizeOfArray('feed.entry[i].gd$email');
      j := 0;
      while j < numEmailAddresses do
        begin
          emailAddress := json.StringOf('feed.entry[i].gd$email[j].address');
          if (json.LastMethodSuccess = True) then
            begin
              WriteLn('email address: ' + emailAddress);
            end;
          j := j + 1;
        end;

      i := i + 1;
    end;

  //  A sample Google Contacts JSON response:

  //  	{ 
  //  	  "version": "1.0",
  //  	  "encoding": "UTF-8",
  //  	  "feed": { 
  //  	    "xmlns": "http://www.w3.org/2005/Atom",
  //  	    "xmlns$openSearch": "http://a9.com/-/spec/opensearch/1.1/",
  //  	    "xmlns$gContact": "http://schemas.google.com/contact/2008",
  //  	    "xmlns$batch": "http://schemas.google.com/gdata/batch",
  //  	    "xmlns$gd": "http://schemas.google.com/g/2005",
  //  	    "gd$etag": "\"QHw5eTVSLyt7I2A9XRFaE0kNTwI.\"",
  //  	    "id": { 
  //  	      "$t": "chilkat.support@gmail.com"
  //  	    },
  //  	    "updated": { 
  //  	      "$t": "2016-11-17T01:57:41.221Z"
  //  	    },
  //  	    "category": [
  //  	      { 
  //  	        "scheme": "http://schemas.google.com/g/2005#kind",
  //  	        "term": "http://schemas.google.com/contact/2008#contact"
  //  	      }
  //  	    ],
  //  	    "title": { 
  //  	      "$t": "Chilkat Support's Contacts"
  //  	    },
  //  	    "link": [
  //  	      { 
  //  	        "rel": "alternate",
  //  	        "type": "text/html",
  //  	        "href": "https://www.googleapis.com/"
  //  	      },
  //  	      { 
  //  	        "rel": "http://schemas.google.com/g/2005#feed",
  //  	        "type": "application/atom+xml",
  //  	        "href": "https://www.googleapis.com/m8/feeds/contacts/chilkat.support%40gmail.com/full"
  //  	      },
  //  	      { 
  //  	        "rel": "http://schemas.google.com/g/2005#post",
  //  	        "type": "application/atom+xml",
  //  	        "href": "https://www.googleapis.com/m8/feeds/contacts/chilkat.support%40gmail.com/full"
  //  	      },
  //  	      { 
  //  	        "rel": "http://schemas.google.com/g/2005#batch",
  //  	        "type": "application/atom+xml",
  //  	        "href": "https://www.googleapis.com/m8/feeds/contacts/chilkat.support%40gmail.com/full/batch"
  //  	      },
  //  	      { 
  //  	        "rel": "self",
  //  	        "type": "application/atom+xml",
  //  	        "href": "https://www.googleapis.com/m8/feeds/contacts/chilkat.support%40gmail.com/full?max-results=25&alt=json"
  //  	      },
  //  	      { 
  //  	        "rel": "next",
  //  	        "type": "application/atom+xml",
  //  	        "href": "https://www.googleapis.com/m8/feeds/contacts/chilkat.support%40gmail.com/full?max-results=25&alt=json&start-index=26"
  //  	      }
  //  	    ],
  //  	    "author": [
  //  	      { 
  //  	        "name": { 
  //  	          "$t": "Chilkat Support"
  //  	        },
  //  	        "email": { 
  //  	          "$t": "chilkat.support@gmail.com"
  //  	        }
  //  	      }
  //  	    ],
  //  	    "generator": { 
  //  	      "version": "1.0",
  //  	      "uri": "http://www.google.com/m8/feeds",
  //  	      "$t": "Contacts"
  //  	    },
  //  	    "openSearch$totalResults": { 
  //  	      "$t": "350"
  //  	    },
  //  	    "openSearch$startIndex": { 
  //  	      "$t": "1"
  //  	    },
  //  	    "openSearch$itemsPerPage": { 
  //  	      "$t": "25"
  //  	    },
  //  	    "entry": [
  //  	      { 
  //  	        "id": { 
  //  	          "$t": "http://www.google.com/m8/feeds/contacts/chilkat.support%40gmail.com/base/0"
  //  	        },
  //  	        "gd$etag": "\"SX8zcTVSLyt7I2A9WxBXFU4MQwI.\"",
  //  	        "updated": { 
  //  	          "$t": "2010-01-26T20:07:48.189Z"
  //  	        },
  //  	        "app$edited": { 
  //  	          "xmlns$app": "http://www.w3.org/2007/app",
  //  	          "$t": "2010-01-26T20:07:48.189Z"
  //  	        },
  //  	        "category": [
  //  	          { 
  //  	            "scheme": "http://schemas.google.com/g/2005#kind",
  //  	            "term": "http://schemas.google.com/contact/2008#contact"
  //  	          }
  //  	        ],
  //  	        "title": { 
  //  	          "$t": "Joe Sample"
  //  	        },
  //  	        "link": [
  //  	          { 
  //  	            "rel": "http://schemas.google.com/contacts/2008/rel#photo",
  //  	            "type": "image/*",
  //  	            "href": "https://www.googleapis.com/m8/feeds/photos/media/chilkat.support%40gmail.com/0"
  //  	          },
  //  	          { 
  //  	            "rel": "self",
  //  	            "type": "application/atom+xml",
  //  	            "href": "https://www.googleapis.com/m8/feeds/contacts/chilkat.support%40gmail.com/full/0"
  //  	          },
  //  	          { 
  //  	            "rel": "edit",
  //  	            "type": "application/atom+xml",
  //  	            "href": "https://www.googleapis.com/m8/feeds/contacts/chilkat.support%40gmail.com/full/0"
  //  	          }
  //  	        ],
  //  	        "gd$name": { 
  //  	          "gd$fullName": { 
  //  	            "$t": "Joe Sample"
  //  	          },
  //  	          "gd$givenName": { 
  //  	            "$t": "Joe"
  //  	          },
  //  	          "gd$familyName": { 
  //  	            "$t": "Sample"
  //  	          }
  //  	        },
  //  	        "gd$email": [
  //  	          { 
  //  	            "address": "somebody@gmail.com",
  //  	            "primary": "true",
  //  	            "rel": "http://schemas.google.com/g/2005#other"
  //  	          }
  //  	        ]
  //  	      },
  //  		... more entries ...
  //  	}


  jsonToken.Free;
  gAuth.Free;
  rest.Free;
  sbResponseBody.Free;
  json.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.