(Visual FoxPro) Payeezy HMAC Computation

Demonstrates how to calculate the HMAC for a Payeezy REST request.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

LOCAL loCrypt
LOCAL loPrng
LOCAL lnSuccess
LOCAL lcApiKey
LOCAL lcApiSecret
LOCAL lcToken
LOCAL lcNonce
LOCAL loDtNow
LOCAL loSbTimestamp
LOCAL lcTimestamp
LOCAL loJson
LOCAL loSbHmacData
LOCAL lcHexHash
LOCAL loSbBase64Hash

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

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Crypt2')
loCrypt = CreateObject('Chilkat.Crypt2')
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Prng')
loPrng = CreateObject('Chilkat.Prng')

* An API key such as y6pWAJNyJyjGv66IsVuWnklkKUPFbb0a
lcApiKey = "my_api_key"
* An API secret such as 86fbae7030253af3cd15faef2a1f4b67353e41fb6799f576b5093ae52901e6f7
lcApiSecret = "my_api_secret"
* A token such as fdoa-a480ce8951daa73262734cf102641994c1e55e7cdf4c02b6
lcToken = "my_merchant_token"

* The nonce is a random number (bytes), something like "6057786719490086000"
lcNonce = loPrng.GenRandom(8,"decimal")
? "nonce = " + lcNonce

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.CkDateTime')
loDtNow = CreateObject('Chilkat.CkDateTime')
loDtNow.SetFromCurrentSystemTime()
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.StringBuilder')
loSbTimestamp = CreateObject('Chilkat.StringBuilder')
* Get the epoch timestamp in seconds
loSbTimestamp.Append(loDtNow.GetAsUnixTimeStr(0))
* Change it to milliseconds
loSbTimestamp.Append("000")
* The timestamp is a number similar to this: 1546011905000 (which is a timestamp taken on 28-Dec-2018).
lcTimestamp = loSbTimestamp.GetAsString()
? "timestamp = " + lcTimestamp

* Generate the following JSON request body:
* 	{
* 	  "merchant_ref": "Astonishing-Sale",
* 	  "transaction_type": "authorize",
* 	  "method": "token",
* 	  "amount": "200",
* 	  "currency_code": "USD",
* 	  "token": {
* 	    "token_type": "FDToken",
* 	    "token_data": {
* 	      "type": "visa",
* 	      "value": "2537446225198291",
* 	      "cardholder_name": "JohnSmith",
* 	      "exp_date": "1030",
* 	      "special_payment": "B"
* 	    }
* 	  }
* 	}

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.JsonObject')
loJson = CreateObject('Chilkat.JsonObject')
loJson.UpdateString("merchant_ref","Astonishing-Sale")
loJson.UpdateString("transaction_type","authorize")
loJson.UpdateString("method","token")
loJson.UpdateString("amount","200")
loJson.UpdateString("currency_code","USD")
loJson.UpdateString("token.token_type","FDToken")
loJson.UpdateString("token.token_data.type","visa")
loJson.UpdateString("token.token_data.value","2537446225198291")
loJson.UpdateString("token.token_data.cardholder_name","JohnSmith")
loJson.UpdateString("token.token_data.exp_date","1030")
loJson.UpdateString("token.token_data.special_payment","B")

* string hashData = apiKey + nonce + timestamp + token + jsonString;
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.StringBuilder')
loSbHmacData = CreateObject('Chilkat.StringBuilder')
loSbHmacData.Append(lcApiKey)
loSbHmacData.Append(lcNonce)
loSbHmacData.Append(lcTimestamp)
loSbHmacData.Append(lcToken)
loSbHmacData.Append(loJson.Emit())

* HMAC the data to produce a hex string.
loCrypt.EncodingMode = "hexlower"
loCrypt.MacAlgorithm = "hmac"
loCrypt.SetMacKeyString(lcApiSecret)
loCrypt.HashAlgorithm = "sha256"
loCrypt.Charset = "utf-8"
lcHexHash = loCrypt.MacStringENC(loSbHmacData.GetAsString())

* Now base64 encode the hex string:
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.StringBuilder')
loSbBase64Hash = CreateObject('Chilkat.StringBuilder')
loSbBase64Hash.Append(lcHexHash)
loSbBase64Hash.Encode("base64","utf-8")

? "This is the Authorization header to be sent with the payeezy request:"
? "Authorization: " + loSbBase64Hash.GetAsString()

RELEASE loCrypt
RELEASE loPrng
RELEASE loDtNow
RELEASE loSbTimestamp
RELEASE loJson
RELEASE loSbHmacData
RELEASE loSbBase64Hash