(Delphi DLL) Google Maps Geolocation Request

Demonstrates how make a Google Maps Geolocation REST API request.

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

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
rest: HCkRest;
bTls: Boolean;
port: Integer;
bAutoReconnect: Boolean;
success: Boolean;
json: HCkJsonObject;
aCellTowers: HCkJsonArray;
oCellTower: HCkJsonObject;
aWifi: HCkJsonArray;
oPoint: HCkJsonObject;
responseJson: PWideChar;
jsonResp: HCkJsonObject;
jsonLoc: HCkJsonObject;
latitude: PWideChar;
longitude: PWideChar;
accuracy: PWideChar;

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 := CkRest_Create();

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

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

// Add your API key as a query parameter
CkRest_AddQueryParam(rest,'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 := CkJsonObject_Create();
CkJsonObject_AppendInt(json,'homeMobileCountryCode',310);
CkJsonObject_AppendInt(json,'homeMobileNetworkCode',260);
CkJsonObject_AppendString(json,'radioType','gsm');
CkJsonObject_AppendString(json,'carrier','T-Mobile');
aCellTowers := CkJsonObject_AppendArray(json,'cellTowers');
CkJsonArray_AddObjectAt(aCellTowers,0);
oCellTower := CkJsonArray_ObjectAt(aCellTowers,0);
CkJsonObject_AppendInt(oCellTower,'cellId',39627456);
CkJsonObject_AppendInt(oCellTower,'locationAreaCode',40495);
CkJsonObject_AppendInt(oCellTower,'mobileCountryCode',310);
CkJsonObject_AppendInt(oCellTower,'mobileNetworkCode',260);
CkJsonObject_AppendInt(oCellTower,'age',0);
CkJsonObject_AppendInt(oCellTower,'signalStrength',-95);
CkJsonObject_Dispose(oCellTower);
CkJsonArray_Dispose(aCellTowers);
aWifi := CkJsonObject_AppendArray(json,'wifiAccessPoints');
CkJsonArray_AddObjectAt(aWifi,0);
oPoint := CkJsonArray_ObjectAt(aWifi,0);
CkJsonObject_AppendString(oPoint,'macAddress','01:23:45:67:89:AB');
CkJsonObject_AppendInt(oPoint,'signalStrength',8);
CkJsonObject_AppendInt(oPoint,'age',0);
CkJsonObject_AppendInt(oPoint,'signalToNoiseRatio',-65);
CkJsonObject_AppendInt(oPoint,'channel',8);
CkJsonObject_Dispose(oPoint);
CkJsonArray_AddObjectAt(aWifi,1);
oPoint := CkJsonArray_ObjectAt(aWifi,1);
CkJsonObject_AppendString(oPoint,'macAddress','01:23:45:67:89:AC');
CkJsonObject_AppendInt(oPoint,'signalStrength',4);
CkJsonObject_AppendInt(oPoint,'age',0);
CkJsonObject_Dispose(oPoint);
CkJsonArray_Dispose(aWifi);

responseJson := CkRest__fullRequestString(rest,'POST','/geolocation/v1/geolocate',CkJsonObject__emit(json));
if (CkRest_getLastMethodSuccess(rest) <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

// When successful, the response code is 200.
if (CkRest_getResponseStatusCode(rest) <> 200) then
  begin
    // Examine the request/response to see what happened.
    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 JSON: ' + responseJson);
    Memo1.Lines.Add('---');
    Memo1.Lines.Add('LastRequestStartLine: ' + CkRest__lastRequestStartLine(rest));
    Memo1.Lines.Add('LastRequestHeader: ' + CkRest__lastRequestHeader(rest));
    Exit;
  end;

CkJsonObject_putEmitCompact(json,False);
Memo1.Lines.Add('JSON request body: ' + CkJsonObject__emit(json));

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

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

jsonResp := CkJsonObject_Create();
CkJsonObject_Load(jsonResp,responseJson);

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

accuracy := CkJsonObject__stringOf(jsonResp,'accuracy');
Memo1.Lines.Add('accuracy = ' + accuracy);

CkRest_Dispose(rest);
CkJsonObject_Dispose(json);
CkJsonObject_Dispose(jsonResp);

end;