Pascal (Lazarus/Delphi)

Google Maps Geolocation Request

See more REST Examples

Demonstrates how make a Google Maps Geolocation REST API request. 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.JsonArray,
  Chilkat.Rest,
  Chilkat.JsonObject;

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

procedure RunDemo;
var
  success: Boolean;
  rest: TRest;
  bTls: Boolean;
  port: Integer;
  bAutoReconnect: Boolean;
  json: TJsonObject;
  aCellTowers: TJsonArray;
  oCellTower: TJsonObject;
  aWifi: TJsonArray;
  oPoint: TJsonObject;
  responseJson: string;
  jsonResp: TJsonObject;
  jsonLoc: TJsonObject;
  latitude: string;
  longitude: string;
  accuracy: string;

begin
  success := False;

  //  This example duplicates the following CURL request:
  //  curl -d @your_filename.json -H "Content-Type: application/json" -i "https://www.googleapis.com/geolocation/v1/geolocate?key=YOUR_API_KEY"

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

  rest := TRest.Create;

  //  Connect to the Google API REST server.
  bTls := True;
  port := 443;
  bAutoReconnect := True;
  success := rest.Connect('www.googleapis.com',port,bTls,bAutoReconnect);

  //  Add the Content-Type request header.
  rest.AddHeader('Content-Type','application/json');

  //  Add your API key as a query parameter
  rest.AddQueryParam('key','YOUR_API_KEY');

  //  The JSON query is contained in the body of the HTTP POST.
  //  This is a sample query (which we'll dynamically build in this example)
  //  { 
  //   "homeMobileCountryCode": 310,
  //   "homeMobileNetworkCode": 260,
  //   "radioType": "gsm",
  //   "carrier": "T-Mobile",
  //   "cellTowers": [
  //    {
  //     "cellId": 39627456,
  //     "locationAreaCode": 40495,
  //     "mobileCountryCode": 310,
  //     "mobileNetworkCode": 260,
  //     "age": 0,
  //     "signalStrength": -95
  //    }
  //   ],
  //   "wifiAccessPoints": [
  //    { 
  //     "macAddress": "01:23:45:67:89:AB",
  //     "signalStrength": 8,
  //     "age": 0,
  //     "signalToNoiseRatio": -65,
  //     "channel": 8
  //    },
  //    { 
  //     "macAddress": "01:23:45:67:89:AC",
  //     "signalStrength": 4,
  //     "age": 0
  //    }
  //   ]
  //  }

  json := TJsonObject.Create;
  json.AppendInt('homeMobileCountryCode',310);
  json.AppendInt('homeMobileNetworkCode',260);
  json.AppendString('radioType','gsm');
  json.AppendString('carrier','T-Mobile');

  aCellTowers := TJsonArray.Create;
  json.AppendArray2('cellTowers',aCellTowers);

  oCellTower := TJsonObject.Create;
  aCellTowers.AddObjectAt2(0,oCellTower);
  oCellTower.AppendInt('cellId',39627456);
  oCellTower.AppendInt('locationAreaCode',40495);
  oCellTower.AppendInt('mobileCountryCode',310);
  oCellTower.AppendInt('mobileNetworkCode',260);
  oCellTower.AppendInt('age',0);
  oCellTower.AppendInt('signalStrength',-95);

  aWifi := TJsonArray.Create;
  json.AppendArray2('wifiAccessPoints',aWifi);

  oPoint := TJsonObject.Create;
  aWifi.AddObjectAt2(0,oPoint);
  oPoint.AppendString('macAddress','01:23:45:67:89:AB');
  oPoint.AppendInt('signalStrength',8);
  oPoint.AppendInt('age',0);
  oPoint.AppendInt('signalToNoiseRatio',-65);
  oPoint.AppendInt('channel',8);

  aWifi.AddObjectAt2(1,oPoint);
  oPoint.AppendString('macAddress','01:23:45:67:89:AC');
  oPoint.AppendInt('signalStrength',4);
  oPoint.AppendInt('age',0);

  responseJson := rest.FullRequestString('POST','/geolocation/v1/geolocate',json.Emit());
  if (rest.LastMethodSuccess = False) then
    begin
      WriteLn(rest.LastErrorText);
      Exit;
    end;

  //  When successful, the response code is 200.
  if (rest.ResponseStatusCode <> 200) then
    begin
      //  Examine the request/response to see what happened.
      WriteLn('response status code = ' + rest.ResponseStatusCode);
      WriteLn('response status text = ' + rest.ResponseStatusText);
      WriteLn('response header: ' + rest.ResponseHeader);
      WriteLn('response JSON: ' + responseJson);
      WriteLn('---');
      WriteLn('LastRequestStartLine: ' + rest.LastRequestStartLine);
      WriteLn('LastRequestHeader: ' + rest.LastRequestHeader);
      Exit;
    end;

  json.EmitCompact := False;
  WriteLn('JSON request body: ' + json.Emit());

  //  The JSON response should look like this:
  //  { 
  //   "location": {
  //    "lat": 37.4248297,
  //    "lng": -122.07346549999998
  //   },
  //   "accuracy": 1145.0
  //  }

  WriteLn('JSON response: ' + responseJson);

  jsonResp := TJsonObject.Create;
  jsonResp.Load(responseJson);

  jsonLoc := TJsonObject.Create;
  jsonResp.ObjectOf2('location',jsonLoc);

  //  Any JSON value can be obtained as a string..
  latitude := jsonLoc.StringOf('lat');
  WriteLn('latitude = ' + latitude);
  longitude := jsonLoc.StringOf('lng');
  WriteLn('longitude = ' + longitude);

  accuracy := jsonResp.StringOf('accuracy');
  WriteLn('accuracy = ' + accuracy);


  rest.Free;
  json.Free;
  aCellTowers.Free;
  oCellTower.Free;
  aWifi.Free;
  oPoint.Free;
  jsonResp.Free;
  jsonLoc.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.