(Delphi DLL) URL Signing for Google Maps API

Demonstrates how to sign a URL for the Google Maps API.

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, Crypt2;

...

procedure TForm1.Button1Click(Sender: TObject);
var
crypt: HCkCrypt2;
sig: PWideChar;

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

crypt := CkCrypt2_Create();

// The output will be modified Base64.
// Modified Base64 for URLs replaces the '+' and '/' characters 
// of standard Base64 with '-' and '_' respectively, so that these 
// Base64 signatures no longer need to be URL-encoded.
CkCrypt2_putEncodingMode(crypt,'modBase64');

// Set the hash algorithm to sha-1
CkCrypt2_putHashAlgorithm(crypt,'sha-1');

// Set the HMAC key (this is the private key provided by Google)
CkCrypt2_SetHmacKeyEncoded(crypt,'vNIXE0xscrmjlyV-12Nj_BvUPaw=','modBase64');

// Compute the URL signature
sig := CkCrypt2__hmacStringENC(crypt,'/maps/api/geocode/json?address=New+York&sensor=false&client=clientID');

// The result should be KrU1TzVQM7Ur0i8i7K3huiw3MsA=
Memo1.Lines.Add(sig);

CkCrypt2_Dispose(crypt);

end;