README.md

NodeJS Server Example

This is an example of how to create the server side in nodeJS for the payment form.

Requirements

You need to install node.js LTS version.

Payment hash verification

Payment hash must be validated on the server side to prevent the exposure of your personal hash key.

Server side

const express = require('express')
const hmacSHA256 = require('crypto-js/hmac-sha256')
const Hex = require('crypto-js/enc-hex')
const app = express()

// In a separate file
exports.createFormToken = async paymentConf => {
  // format: 123456789
  const username = '~~CHANGE_ME_USER~~'

  // format: testprivatekey_XXXXXXX
  const password = '~~CHANGE_ME_PASSWORD~~'

  // format: api.my.psp.domain.name without https
  const endpoint = '~~CHANGE_ME_ENDPOINT_NO_HTTPS~~'

  const createPaymentEndpoint = `https://${username}:${password}@${endpoint}/api-payment/V4/Charge/CreatePayment`

  try {
    const response = await axios.post(createPaymentEndpoint, paymentConf, {
      headers: {
        'Content-Type': 'application/json'
      }
    })
    if (!response?.data?.answer?.formToken) throw response
    return response.data.answer.formToken
  } catch (error) {
    throw error
  }
}
/**
 * Generates a payment token for the given configuration
 */
app.post('/createPayment', async (req, res) => {
  const paymentConf = req.body.paymentConf

  try {
    const formToken = await createFormToken(paymentConf)
    res.send(formToken)
  } catch (error) {
    res.status(500).send(error)
  }
})

(...)
// Validates the given payment data (hash)
app.post('/validatePayment', (req, res) => {
  const answer = req.body.clientAnswer
  const hash = req.body.hash
  const answerHash = Hex.stringify(
    hmacSHA256(JSON.stringify(answer), 'CHANGE_ME: HMAC SHA256 KEY')
  )
  if (hash === answerHash) res.status(200).send('Valid payment')
  else res.status(500).send('Payment hash mismatch')
})
(...)

Client side

await KR.onSubmit(paymentData => {
  const response = await fetch('http://localhost:3000/validatePayment', {
    method: "POST",
    body: JSON.stringify(paymentData)
  })

  if (response.status === 200) this.message = 'Payment successful!'
  return false
})

Run it from github

You can run the example node.js server by running:

cd examples/server
npm i
npm run start