(Delphi DLL) Simple REST Example

Demonstrates a very simple RESTful API call to get a stock time series daily (quotes) from Alpha Vantage.

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, Rest;

...

procedure TForm1.Button1Click(Sender: TObject);
var
rest: HCkRest;
bTls: Boolean;
port: Integer;
bAutoReconnect: Boolean;
success: Boolean;
responseJson: PWideChar;

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

rest := CkRest_Create();

// Connect to the REST server.
bTls := True;
port := 443;
bAutoReconnect := True;
success := CkRest_Connect(rest,'www.alphavantage.co',port,bTls,bAutoReconnect);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

// Get a stock quote:
// Sending GET request to https://www.alphavantage.co/query?function=TIME_SERIES_DAILY&symbol=MSFT&apikey=my_api_key
success := CkRest_AddQueryParam(rest,'function','TIME_SERIES_DAILY');
success := CkRest_AddQueryParam(rest,'symbol','AAPL');
success := CkRest_AddQueryParam(rest,'apikey','my_api_key');
responseJson := CkRest__fullRequestNoBody(rest,'GET','/query');
if (CkRest_getLastMethodSuccess(rest) <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

Memo1.Lines.Add(responseJson);

// Sample response:
// {
//     "Meta Data": {
//         "1. Information": "Daily Prices (open, high, low, close) and Volumes",
//         "2. Symbol": "AAPL",
//         "3. Last Refreshed": "2019-12-06",
//         "4. Output Size": "Compact",
//         "5. Time Zone": "US/Eastern"
//     },
//     "Time Series (Daily)": {
//         "2019-12-06": {
//             "1. open": "267.4800",
//             "2. high": "271.0000",
//             "3. low": "267.3000",
//             "4. close": "270.7100",
//             "5. volume": "25447644"
//         },
//         "2019-12-05": {
//             "1. open": "263.7900",
//             "2. high": "265.8900",
//             "3. low": "262.7300",
//             "4. close": "265.5800",
//             "5. volume": "18661343"
//         },
//         "2019-12-04": {
//             "1. open": "261.0700",
//             "2. high": "263.3100",
//             "3. low": "260.6800",
//             "4. close": "261.7400",
//             "5. volume": "16810388"
//         },
// ...
//         "2019-07-18": {
//             "1. open": "204.0000",
//             "2. high": "205.8800",
//             "3. low": "203.7000",
//             "4. close": "205.6600",
//             "5. volume": "18582161"
//         }
//     }
// }

CkRest_Dispose(rest);

end;