(Tcl) 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/

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load ./chilkat.dll

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

set 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>"

set gzip [new_CkGzip]

set gzOrderData [CkGzip_compressStringENC $gzip $strHtml "utf-8" "base64"]

set xml [new_CkXml]

CkXml_put_Tag $xml "keyValuePairs"

CkXml_NewChild2 $xml "orderData" $gzOrderData

# required, The payment deadline; the payment needs to occur within the specified time value.
set 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.
set countryCode "GB"
CkXml_NewChild2 $xml "countryCode" $countryCode

# optional
set 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.
set merchantReference "paymentTest1234"
CkXml_NewChild2 $xml "merchantReference" $merchantReference

# required, The merchant account identifier you want to process the (transaction) request with.
set merchantAccount "ChilkatSoftwareIncCOM"
CkXml_NewChild2 $xml "merchantAccount" $merchantAccount

# required.  10000 for $100.00
set paymentAmount "10000"
CkXml_NewChild2 $xml "paymentAmount" $paymentAmount

# required, The three-character ISO currency code
set currencyCode "GBP"
CkXml_NewChild2 $xml "currencyCode" $currencyCode

# required.
set 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.  
set shopperReference "somebody@example.com"
CkXml_NewChild2 $xml "shopperReference" $shopperReference

# optional
set 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.
set shipBeforeDate "2019-06-04"
CkXml_NewChild2 $xml "shipBeforeDate" $shipBeforeDate

CkXml_SortByTag $xml 1

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

set sbTags [new_CkStringBuilder]

set sbValues [new_CkStringBuilder]

set sbContent [new_CkStringBuilder]

set n [CkXml_get_NumChildren $xml]
set i 0
while {$i < $n} {
    if {$i > 0} then {
        CkStringBuilder_Append $sbTags ":"
        CkStringBuilder_Append $sbValues ":"
    }

    CkXml_GetChild2 $xml $i
    CkStringBuilder_Append $sbTags [CkXml_tag $xml]

    CkStringBuilder_SetString $sbContent [CkXml_content $xml]
    set numReplaced [CkStringBuilder_Replace $sbContent "\\" "\\\\"]
    set numReplaced [CkStringBuilder_Replace $sbContent ":" "\\:"]
    CkStringBuilder_AppendSb $sbValues $sbContent
    CkXml_GetParent2 $xml

    set i [expr $i + 1]
}

set sbSigningStr [new_CkStringBuilder]

CkStringBuilder_AppendSb $sbSigningStr $sbTags
CkStringBuilder_Append $sbSigningStr ":"
CkStringBuilder_AppendSb $sbSigningStr $sbValues

set crypt [new_CkCrypt2]

CkCrypt2_put_HashAlgorithm $crypt "sha256"
CkCrypt2_put_MacAlgorithm $crypt "hmac"

set hmacKey "934D1E806DDD99595EB430076FD7F8E4D12D0A3F51243A4C0C3897703118E739"
CkCrypt2_SetMacKeyEncoded $crypt $hmacKey "hex"

CkCrypt2_put_EncodingMode $crypt "base64"
set merchantSig [CkCrypt2_hmacStringENC $crypt [CkStringBuilder_getAsString $sbSigningStr]]

puts "$merchantSig"

delete_CkGzip $gzip
delete_CkXml $xml
delete_CkStringBuilder $sbTags
delete_CkStringBuilder $sbValues
delete_CkStringBuilder $sbContent
delete_CkStringBuilder $sbSigningStr
delete_CkCrypt2 $crypt