Consultation

3.41. Connecting Party Callbacks

General information

If Connecting Party specified a callback URL, Payment Gateway sends an HTTP GET message to the callback URL whenever transaction reaches final status, no matter if the result is approved, declined or other final status. This gives Connecting Party better control of how the transaction is processed, for example to add appropriate records to Connecting Party internal accounting system.

Warning

Connecting Party server needs to respond to this GET request with 200 OK status RFC, or else Payment Gateway will continue to send the callback 30 times for 14 days applying the progressive timeline.

Please remember, callbacks are guaranteed to report Connecting Party about transaction status. Connecting Party on their side must provide a means of preventing receiving the same callback twice – in case of network or other technical problems. It is recommended to check status, type, orderid and client_orderid to prevent duplication of transactions on Connecting Party side.

Callback URLs can be specified by Connecting Party in the following ways:

  • By sending server_callback_url or notify_url in initial transaction request. If server_callback_url is sent, Connecting Party will receive a callback only for the initial transaction (ex. sale approved). If notify_url is sent instead, Connecting Party will receive a callback for the initial transaction (ex. sale approved) and for any new transaction types applied to the same transaction (ex. reversal, chargeback).
  • By specifying the callback URL on endpoint level. Each transaction type can have it’s own callback URL.

Only the following ports are allowed in callback URL:

  • for HTTP 80, 8080
  • for HTTPS 443, 8443

Customizable Callback URL

Simple callback URL contains all parameters listed in Callback Parameters. Customizable callback URL is a fully defined URL with all the parameters Connecting Party target page or script would require. Customizable URL allows Connecting Party to define own parameter names, whereas the actual parameters values are defined by use of macros with the following format ${parameter_name}. Thus pay.billblend.com substitutes respective parameter values into final customized URL before calling it. Available macros are listed in Callback Macros.

Example of simple callback URL:

https://connectingparty.com/sale_completed.php

Example of customized callback URL:

https://connectingparty.com/sale_completed.php?cardholder_name=${name}&tx_status=${status}&order_id=${merchant_order}

Callback Parameters

Note

The system automatically adds the following parameters to callback URL.

* – these parameters are not defined by default. Please contact tech support to include these fields in callback.

Callback Parameter Description
status See Status List for details.
merchant_order Connecting Party order identifier, same as client_orderid.
client_orderid Connecting Party order identifier.
orderid pay.billblend.com transaction id.
type Transaction type, sale reversal chargeback
amount Actual transaction amount. This value can be changed during the transaction flow.
currency Transaction currency.
descriptor Payment descriptor of the gate through which the transaction has been processed.
error_code Error Code. This field won’t be included in callback in case transaction status=approved.
error_message Error Message. This field won’t be included in callback in case transaction status=approved.
name Cardholder Name.
email Payer’s email.
country * Payer’s country (two-letter country code). Please see Country and State Codes for a list of valid country codes.
state * Payer’s state . Please see Country and State Codes for a list of valid state codes. Mandatory for USA, Canada and Australia.
city * Payer’s city.
zip_code * Payer’s ZIP code.
address1 * Payer’s address line 1.
approval-code Authorization approval code, if any.
last-four-digits Last four digits of Payer’s credit card number.
bin Bank BIN of Payer’s credit card.
card-type Type of Payer’s credit card (VISA, MASTERCARD, etc).
phone Payer’s phone number.
bank-name Payer’s bank name.
card-exp-month Card expiration month.
card-exp-year Card expiration year.
gate-partial-reversal Processing gate support partial reversal (enabled or disabled).
gate-partial-capture Processing gate support partial capture (enabled or disabled).
reason-code Reason code for chargeback or fraud operation.
processor-rrn Bank Retrieval Reference Number.
comment Comment in case of Return transaction
rapida-balance Current balance for Connecting Party registered in Rapida system (only if balance check active)
control Checksum is used to ensure that it is pay.billblend.com (and not a fraudster) that initiates the callback to Connecting Party. This is SHA-1 checksum of the concatenation status + orderid + merchant_order + merchant_control. The callback script MUST check this parameter by comparing it to SHA-1 checksum of the above concatenation.
merchantdata The value passed by Connecting Party in initial request.
serial-number Serial number of the request.
processor-tx-id Transaction id set by processor.
processor-auth-credit-code Reserved
card-hash-id Unique hash of the particular card, does not change.
verified-3d-status Will return AUTHENTICATED if a transaction was approved by 3DS.
processor-credit-rrn Retrieval Reference Number set by acquirer.
processor-credit-arn Acquirer card reference number for credit card.
processor-debit-arn Acquirer card reference number for debit card.
eci Electronic Commerce Indicator (Visa).
ips-src-payment-product-code Code for card set by multinational financial service. (Visa/Mastercard).
ips-src-payment-product-name Decrypted code for card set by multinational financial service. (Visa/Mastercard).
ips-src-payment-type-code Type of card code set by multinational financial service. (Visa/Mastercard).
ips-src-payment-type-name Decrypted code for type of card set by multinational financial service. (Visa/Mastercard).
card-country-alpha-three-code Three letter country code of source card issuer. See Card Country Codes for details.
destination-card-country-alpha-three-code Three letter country code of destination card issuer. See Card Country Codes for details.
initial-amount Amount, set in initiating transaction, without any fees or commissions. This value can’t change during the transaction flow.
seller-commission * Total commission for processed transaction.
acquirer-commission * Acquirer commission for processed transaction.
exchange-rate * Basic exchange rate for currency conversion.
effective-exchange-rate * Actual exchange rate, applied during currency conversion.
motivational-message * This is an optional message which contains extended information about the reason for the declined transaction.
orig-amount Contains the original request amount if it was converted on auxiliary endpoint in Parallel form integration.
orig-currency Contains the original request currency if it was converted on auxiliary endpoint in Parallel form integration.

Callback Macros

pay.billblend.com Callback Macros name Description
${status} Transaction status, ex. approved, declined, processing, etc.
${merchant_order} Connecting Party order identifier, same as client_orderid.
${orderid} pay.billblend.com transaction id.
${type} Transaction type, ex. sale, return, chargeback, etc.
${amount} Transaction amount.
${descriptor} Payment descriptor of the gate through which the transaction has been processed.
${error_message} Error message: when ${status} is declined.
${name} Cardholder Name.
${email} Payer’s email.
${last-four-digits} Last four digits of Payer’s credit card number.
${bin} Bank BIN of Payer’s credit card.
${card-type} Type of Payer’s credit card (VISA, MASTERCARD, etc).
${card-exp-month} Card expiration month.
${card-exp-year} Card expiration year.
${gate-partial-reversal} Processing gate support partial reversal (enabled or disabled).
${gate-partial-capture} Processing gate support partial capture (enabled or disabled).
${reason-code} Reason code for chargeback or fraud operation.
${processor-rrn} Bank Retrieval Reference Number.
${approval-code} Bank approval code.
${comment} Comment in case of Return transaction.
${rapida-balance} Current balance for Connecting Party registered in Rapida system (only if balance check active).
${control} Checksum is used to ensure that it is pay.billblend.com (and not a fraudster) that initiates the callback to Connecting Party. This is SHA-1 checksum of the concatenation status + orderid + merchant_order + merchant_control. The callback script MUST check this parameter by comparing it to SHA-1 checksum of the above concatenation.
${merchantdata} The value passed by Connecting Party in initial request.

Callback Request Example

https://connectingparty.com/api/integration/check/pay/server?token=some_token
&serial-number=b8e5b762-c116-407e-a591-82a458e1
&merchant_order=preauth_1171
&client_orderid=preauth_1171
&processor-tx-id=e0a0572f-2154-737c-8ea7-92410
&orderid=57792
&status=approved
&amount=1.50
&currency=EUR
&descriptor=%D0%90+%D0%94%D0%B5%D0%BD%%D0%B3%D0%B8+-+card+registration
&original-gate-descriptor=%D0%90+%D0%940%BD%D1%8C%D0%B3%D0%B8+-+card+registration&gate-partial-capture=enabled
&type=preauth
&name=CARDHOLDER+NAME
&card-exp-month=6
&card-exp-year=2024
&email=22701231%40example.com
&processor-rrn=21660934567
&approval-code=265470
&control=bbd11a020f6bsdkfgjh23e24def54991bfb63c5&last-four-digits=0214
&bin=220220&card-type=VISA
&phone=%2B71914454778
&bank-name=Rabobank
&card-hash-id=235479750
&card-country-alpha-three-code=RUS
&ips-src-payment-product-code=VISA
&ips-src-payment-product-name=VISA
&ips-src-payment-type-code=Unknown
&ips-src-payment-type-name=VISA+Unknown
&initial-amount=1.50
&transaction-date=2022-06-15+12%3A37%3A02+CEST

Callback to Status Parameters Mapping

Callback parameter Name Status parameter Name
amount amount
approval-code approval-code
bin bin
card-type card-type
last-four-digits last-four-digits
bank-name bank-name
name name
first-name first-name
last-name last-name
country country
state state
city city
zip_code zip_code
address1 address1
card-exp-month card-exp-month
card-exp-year card-exp-year
client_orderid merchant-order-id
comment comment
descriptor descriptor
dest-bin dest-bin
dest-card-type dest-card-type
dest-last-four-digits dest-last-four-digits
dest-bank-name dest-bank-name
email email
purpose purpose
error_code error-code
error_message error-message
gate-partial-capture gate-partial-capture
gate-partial-reversal gate-partial-reversal
loyalty-balance loyalty-balance
loyalty-bonus loyalty-bonus
loyalty-message loyalty-message
loyalty-program loyalty-program
merchant_order merchant-order-id
merchantdata merchantdata
orderid paynet-order-id
original-gate-descriptor original-gate-descriptor
phone phone
processor-rrn processor-rrn
processor-tx-id processor-tx-id
rapida-balance rapida-balance
reason-code reason-code
serial-number serial-number
status status
type transaction-type
initial-amount initial-amount
seller-commission seller-commission
acquirer-commission acquirer-commission
exchange-rate exchange-rate
effective-exchange-rate effective-exchange-rate
card-country-alpha-three-code card-country-alpha-three-code
destination-card-country-alpha-three-code destination-card-country-alpha-three-code

Callback Signature Check Example on Java

You may see an example how to check the callback signature using JAVA programming language below:

import org.junit.Test;

import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import static org.junit.Assert.assertEquals;

public class TestCallbackSignatureExampleTest {

    @Test
    public void test() {
        String digest3 = calculateCallbackSignature("approved", 123, "invoice-1", "AF4B5DE6-3468-424C-A922-C1DAD7CB4509");
        assertEquals("5bc8ee48f9ba37c0fd1e0b052a9bc105c6df87e1", digest3);
    }

    public String calculateCallbackSignature(String aTransactionStatus, long aOrderId, String aMerchantOrderId, String aMerchantControlKey) {
        String text   = aTransactionStatus + aOrderId + aMerchantOrderId + aMerchantControlKey;
        byte[] buffer = text.getBytes(StandardCharsets.UTF_8);
        byte[] shaSum = sha(buffer);
        return toHexString(shaSum);
    }

    /**
    * Calculates the SHA-1 digest and returns the value as a <code>byte[]</code>.
    *
    * @param data
    *            Data to digest
    * @return SHA-1 digest
    */
    private static byte[] sha(byte[] data) {
        try {
            MessageDigest digest = MessageDigest.getInstance("SHA");
            return digest.digest(data);
        } catch (NoSuchAlgorithmException e) {
           throw new IllegalStateException("Couldn't calculate SHA-1 digest", e);
        }
    }

    /**
     * Converts bytes to hex string
     */
    private static String toHexString(byte[] data) {
        StringBuilder sb = new StringBuilder();
        for (byte b : data) {
            String hex = Integer.toHexString(0xff & b);
            if (hex.length() == 1) {
                sb.append('0');
            }
            sb.append(hex);
        }
        return sb.toString();
    }

}

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