(Go) Payeezy HMAC Computation

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

Chilkat Go Downloads Go Package for Windows, MacOS, Linux, Alpine Linux, Solaris

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

    crypt := chilkat.NewCrypt2()
    prng := chilkat.NewPrng()
    var success bool

    // 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")
    fmt.Println("nonce = ", *nonce)

    dtNow := chilkat.NewCkDateTime()
    dtNow.SetFromCurrentSystemTime()
    sbTimestamp := chilkat.NewStringBuilder()
    // 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()
    fmt.Println("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 := chilkat.NewJsonObject()
    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 := chilkat.NewStringBuilder()
    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.SetEncodingMode("hexlower")
    crypt.SetMacAlgorithm("hmac")
    crypt.SetMacKeyString(apiSecret)
    crypt.SetHashAlgorithm("sha256")
    crypt.SetCharset("utf-8")
    hexHash := crypt.MacStringENC(*sbHmacData.GetAsString())

    // Now base64 encode the hex string:
    sbBase64Hash := chilkat.NewStringBuilder()
    sbBase64Hash.Append(*hexHash)
    sbBase64Hash.Encode("base64","utf-8")

    fmt.Println("This is the Authorization header to be sent with the payeezy request:")
    fmt.Println("Authorization: ", *sbBase64Hash.GetAsString())

    crypt.DisposeCrypt2()
    prng.DisposePrng()
    dtNow.DisposeCkDateTime()
    sbTimestamp.DisposeStringBuilder()
    json.DisposeJsonObject()
    sbHmacData.DisposeStringBuilder()
    sbBase64Hash.DisposeStringBuilder()