(Chilkat2-Python) Payeezy HMAC Computation

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

Chilkat2 Python Downloads install with pip pip3 install chilkat2 or download... Python Module for Windows, Linux, Alpine Linux, MacOS, Solaris

import chilkat2

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

crypt = chilkat2.Crypt2()
prng = chilkat2.Prng()

# An API key such as y6pWAJNyJyjGv66IsVuWnklkKUPFbb0a
apiKey = "my_api_key"
# An API secret such as 86fbae7030253af3cd15faef2a1f4b67353e41fb6799f576b5093ae52901e6f7
apiSecret = "my_api_secret"
# A token such as fdoa-a480ce8951daa73262734cf102641994c1e55e7cdf4c02b6
token = "my_merchant_token"

# The nonce is a random number (bytes), something like "6057786719490086000"
nonce = prng.GenRandom(8,"decimal")
print("nonce = " + nonce)

dtNow = chilkat2.CkDateTime()
dtNow.SetFromCurrentSystemTime()
sbTimestamp = chilkat2.StringBuilder()
# Get the epoch timestamp in seconds
sbTimestamp.Append(dtNow.GetAsUnixTimeStr(False))
# Change it to milliseconds
sbTimestamp.Append("000")
# The timestamp is a number similar to this: 1546011905000 (which is a timestamp taken on 28-Dec-2018).
timestamp = sbTimestamp.GetAsString()
print("timestamp = " + timestamp)

# 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"
# 	    }
# 	  }
# 	}

json = chilkat2.JsonObject()
json.UpdateString("merchant_ref","Astonishing-Sale")
json.UpdateString("transaction_type","authorize")
json.UpdateString("method","token")
json.UpdateString("amount","200")
json.UpdateString("currency_code","USD")
json.UpdateString("token.token_type","FDToken")
json.UpdateString("token.token_data.type","visa")
json.UpdateString("token.token_data.value","2537446225198291")
json.UpdateString("token.token_data.cardholder_name","JohnSmith")
json.UpdateString("token.token_data.exp_date","1030")
json.UpdateString("token.token_data.special_payment","B")

# string hashData = apiKey + nonce + timestamp + token + jsonString;
sbHmacData = chilkat2.StringBuilder()
sbHmacData.Append(apiKey)
sbHmacData.Append(nonce)
sbHmacData.Append(timestamp)
sbHmacData.Append(token)
sbHmacData.Append(json.Emit())

# HMAC the data to produce a hex string.
crypt.EncodingMode = "hexlower"
crypt.MacAlgorithm = "hmac"
crypt.SetMacKeyString(apiSecret)
crypt.HashAlgorithm = "sha256"
crypt.Charset = "utf-8"
hexHash = crypt.MacStringENC(sbHmacData.GetAsString())

# Now base64 encode the hex string:
sbBase64Hash = chilkat2.StringBuilder()
sbBase64Hash.Append(hexHash)
sbBase64Hash.Encode("base64","utf-8")

print("This is the Authorization header to be sent with the payeezy request:")
print("Authorization: " + sbBase64Hash.GetAsString())