(Delphi ActiveX) Google Maps Geolocation Request

Demonstrates how make a Google Maps Geolocation REST API request.

Chilkat for Delphi Downloads Chilkat ActiveX DLL for Delphi Chilkat non-ActiveX DLL for Delphi * The examples here use the ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
rest: TChilkatRest;
bTls: Integer;
port: Integer;
bAutoReconnect: Integer;
success: Integer;
json: TChilkatJsonObject;
aCellTowers: IChilkatJsonArray;
oCellTower: IChilkatJsonObject;
aWifi: IChilkatJsonArray;
oPoint: IChilkatJsonObject;
responseJson: WideString;
jsonResp: TChilkatJsonObject;
jsonLoc: IChilkatJsonObject;
latitude: WideString;
longitude: WideString;
accuracy: WideString;

begin
// 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 := TChilkatRest.Create(Self);

// Connect to the Google API REST server.
bTls := 1;
port := 443;
bAutoReconnect := 1;
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 := TChilkatJsonObject.Create(Self);
json.AppendInt('homeMobileCountryCode',310);
json.AppendInt('homeMobileNetworkCode',260);
json.AppendString('radioType','gsm');
json.AppendString('carrier','T-Mobile');
aCellTowers := json.AppendArray('cellTowers');
aCellTowers.AddObjectAt(0);
oCellTower := aCellTowers.ObjectAt(0);
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 := json.AppendArray('wifiAccessPoints');
aWifi.AddObjectAt(0);
oPoint := aWifi.ObjectAt(0);
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.AddObjectAt(1);
oPoint := aWifi.ObjectAt(1);
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 <> 1) then
  begin
    Memo1.Lines.Add(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.
    Memo1.Lines.Add('response status code = ' + IntToStr(rest.ResponseStatusCode));
    Memo1.Lines.Add('response status text = ' + rest.ResponseStatusText);
    Memo1.Lines.Add('response header: ' + rest.ResponseHeader);
    Memo1.Lines.Add('response JSON: ' + responseJson);
    Memo1.Lines.Add('---');
    Memo1.Lines.Add('LastRequestStartLine: ' + rest.LastRequestStartLine);
    Memo1.Lines.Add('LastRequestHeader: ' + rest.LastRequestHeader);
    Exit;
  end;

json.EmitCompact := 0;
Memo1.Lines.Add('JSON request body: ' + json.Emit());

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

Memo1.Lines.Add('JSON response: ' + responseJson);

jsonResp := TChilkatJsonObject.Create(Self);
jsonResp.Load(responseJson);

jsonLoc := jsonResp.ObjectOf('location');
// Any JSON value can be obtained as a string..
latitude := jsonLoc.StringOf('lat');
Memo1.Lines.Add('latitude = ' + latitude);
longitude := jsonLoc.StringOf('lng');
Memo1.Lines.Add('longitude = ' + longitude);

accuracy := jsonResp.StringOf('accuracy');
Memo1.Lines.Add('accuracy = ' + accuracy);
end;