(Delphi DLL) Adyen HMAC Signature Calculation for Hosted Payment Pages

Demonstrates how to do the HMAC Signature Calculation for a hosted payment page (HPP) in Adyen.

For a C# ASP.NET Razor Pages example showing the HTML Form with HMAC signature code, see Adyen HMAC Signature Calculation in C#

For more information, see https://docs.adyen.com/classic-integration/hosted-payment-pages/hmac-signature-calculation/

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, Gzip, StringBuilder, Xml, Crypt2;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
strHtml: PWideChar;
gzip: HCkGzip;
gzOrderData: PWideChar;
xml: HCkXml;
sessionValidity: PWideChar;
countryCode: PWideChar;
shopperLocale: PWideChar;
merchantReference: PWideChar;
merchantAccount: PWideChar;
paymentAmount: PWideChar;
currencyCode: PWideChar;
skinCode: PWideChar;
shopperReference: PWideChar;
shopperEmail: PWideChar;
shipBeforeDate: PWideChar;
sbTags: HCkStringBuilder;
sbValues: HCkStringBuilder;
sbContent: HCkStringBuilder;
n: Integer;
i: Integer;
numReplaced: Integer;
sbSigningStr: HCkStringBuilder;
crypt: HCkCrypt2;
hmacKey: PWideChar;
merchantSig: PWideChar;

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

strHtml := '<table class="od"><tr><th>Description</th><th>Quantity</th><th>Amount</th></tr><tr><td>1 Digital Camera</td><td class="r">1</td><td class="r">100 GBP</td></tr><tr><td class="b">Total</td><td class="r"></td><td class="b r">100.00 GBP</td></tr></table>';

gzip := CkGzip_Create();
gzOrderData := CkGzip__compressStringENC(gzip,strHtml,'utf-8','base64');

xml := CkXml_Create();
CkXml_putTag(xml,'keyValuePairs');

CkXml_NewChild2(xml,'orderData',gzOrderData);

// required, The payment deadline; the payment needs to occur within the specified time value.
sessionValidity := '2019-08-11T10:30:00Z';
CkXml_NewChild2(xml,'sessionValidity',sessionValidity);

// optional.  Normally we'll let Adyen automatically know the country based on the IP address.
// By default, the payment methods offered to a shopper are filtered based on the country the shopper's IP address is mapped to. 
// In this way, shoppers are not offered payment methods that are not available in the country they are carrying out the transaction from. 
// This IP-to-country mapping is not 100% accurate, so if you have already established the country of the shopper, you can set it explicitly 
// in the countryCode parameter.
countryCode := 'GB';
CkXml_NewChild2(xml,'countryCode',countryCode);

// optional
shopperLocale := 'en_GB';
// If not specified, the locale preference is set to en_GB   by default.
// When it is not necessary to include the country-specific part, use only the language code.
// For example: it instead of it_IT to set the locale preferences to Italian.
CkXml_NewChild2(xml,'shopperLocale',shopperLocale);

// required, A reference to uniquely identify the payment. This reference is used in all communication with you about the payment status. 
// We recommend using a unique value per payment; however, it is not a requirement. If you need to provide multiple references for a transaction, 
// you can enter them in this field. Separate each reference value with a hyphen character ("-"). This field has a length restriction: 
// you can enter max. 80 characters.
merchantReference := 'paymentTest1234';
CkXml_NewChild2(xml,'merchantReference',merchantReference);

// required, The merchant account identifier you want to process the (transaction) request with.
merchantAccount := 'ChilkatSoftwareIncCOM';
CkXml_NewChild2(xml,'merchantAccount',merchantAccount);

// required.  10000 for $100.00
paymentAmount := '10000';
CkXml_NewChild2(xml,'paymentAmount',paymentAmount);

// required, The three-character ISO currency code
currencyCode := 'GBP';
CkXml_NewChild2(xml,'currencyCode',currencyCode);

// required.
skinCode := 'S7uWsvfB';
CkXml_NewChild2(xml,'skinCode',skinCode);

// optional, A unique identifier for the shopper, for example, a customer ID.
// We recommend providing this information, as it is used in velocity fraud checks. It is also the key in recurring payments.
// This field is mandatory in recurring payments.  
shopperReference := 'somebody@example.com';
CkXml_NewChild2(xml,'shopperReference',shopperReference);

// optional
shopperEmail := 'somebody@example.com';
CkXml_NewChild2(xml,'shopperEmail',shopperEmail);

// optional, An integer value that adds up to the normal fraud score.
// The value can be either a positive or negative integer.
CkXml_NewChild2(xml,'offset','0');

// Apparently this is a required field.
shipBeforeDate := '2019-06-04';
CkXml_NewChild2(xml,'shipBeforeDate',shipBeforeDate);

CkXml_SortByTag(xml,True);

// Encode...
//  "\" (backslash) as "\\"
//  ":" (colon) as "\:"

sbTags := CkStringBuilder_Create();
sbValues := CkStringBuilder_Create();

sbContent := CkStringBuilder_Create();
n := CkXml_getNumChildren(xml);
i := 0;
while i < n do
  begin
    if (i > 0) then
      begin
        CkStringBuilder_Append(sbTags,':');
        CkStringBuilder_Append(sbValues,':');
      end;
    CkXml_GetChild2(xml,i);
    CkStringBuilder_Append(sbTags,CkXml__tag(xml));

    CkStringBuilder_SetString(sbContent,CkXml__content(xml));
    numReplaced := CkStringBuilder_Replace(sbContent,'\",'\\\");
    numReplaced := CkStringBuilder_Replace(sbContent,':','\\:');
    CkStringBuilder_AppendSb(sbValues,sbContent);
    CkXml_GetParent2(xml);

    i := i + 1;
  end;

sbSigningStr := CkStringBuilder_Create();
CkStringBuilder_AppendSb(sbSigningStr,sbTags);
CkStringBuilder_Append(sbSigningStr,':');
CkStringBuilder_AppendSb(sbSigningStr,sbValues);

crypt := CkCrypt2_Create();
CkCrypt2_putHashAlgorithm(crypt,'sha256');
CkCrypt2_putMacAlgorithm(crypt,'hmac');

hmacKey := '934D1E806DDD99595EB430076FD7F8E4D12D0A3F51243A4C0C3897703118E739';
CkCrypt2_SetMacKeyEncoded(crypt,hmacKey,'hex');

CkCrypt2_putEncodingMode(crypt,'base64');
merchantSig := CkCrypt2__hmacStringENC(crypt,CkStringBuilder__getAsString(sbSigningStr));

Memo1.Lines.Add(merchantSig);

CkGzip_Dispose(gzip);
CkXml_Dispose(xml);
CkStringBuilder_Dispose(sbTags);
CkStringBuilder_Dispose(sbValues);
CkStringBuilder_Dispose(sbContent);
CkStringBuilder_Dispose(sbSigningStr);
CkCrypt2_Dispose(crypt);

end;