B4X

Payeezy HMAC Computation

See more HTTP Misc Examples

Demonstrates how to calculate the HMAC for a Payeezy REST request. B4X

Dim success As Boolean = False

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

Dim crypt As ChilkatCrypt2
crypt.Initialize("crypt")
Dim prng As ChilkatPrng
prng.Initialize

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

'  The nonce is a random number (bytes), something like "6057786719490086000"
Dim nonce As String = prng.GenRandom(8, "decimal")
Log("nonce = " & nonce)

Dim dtNow As ChilkatDateTime
dtNow.Initialize
dtNow.SetFromCurrentSystemTime
Dim sbTimestamp As ChilkatStringBuilder
sbTimestamp.Initialize
'  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).
Dim timestamp As String = sbTimestamp.GetAsString
Log("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"
'  	    }
'  	  }
'  	}

Dim json As ChilkatJsonObject
json.Initialize
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;
Dim sbHmacData As ChilkatStringBuilder
sbHmacData.Initialize
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"
Dim hexHash As String = crypt.MacStringENC(sbHmacData.GetAsString)

'  Now base64 encode the hex string:
Dim sbBase64Hash As ChilkatStringBuilder
sbBase64Hash.Initialize
sbBase64Hash.Append(hexHash)
sbBase64Hash.Encode("base64", "utf-8")

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