Attach Data

With the SDK, you can also attach public data to payments. This data is uploaded to a public blockchain, meaning it cannot be modified or deleted. This can be used as a data timestamping service and can lend transparency to activity in your app.

You may attach data in the following formats:

attachment: { format: 'base64', value: 'ABEiM0RVZneImQCqu8zd7v8=' }

attachment: { format: 'hex', value: '0011223344556677889900AABBCCDDEEFF' }

attachment: { format: 'json', value: {"param1": "value1", "param2": "value2"} }

To attach data, add an attachment field to your payment parameters:

const {HandCashConnect} = require('@handcash/handcash-connect');
const handCashConnect = new HandCashConnect({ 
   appId: '<app-id>', 
   appSecret: '<secret>',
}); 
const account = handCashConnect.getAccountFromAuthToken(token);
const paymentParameters = {
    description: "Hold my beer!🍺",
    payments: [
        { destination: 'nosetwo', currencyCode: 'DUR', sendAmount: 200 },
    ]
    attachment: { format: 'json', value: {"param1": "value1", "param2": "value2"} },
};
const paymentResult = await account.wallet.pay(paymentParameters);
console.log(paymentResult);

// paymentResult
{
  transactionId: '4c7b7cdc18702bb1a09c75a47bc2fa9630545761fbbd53b8c38735c73173e043',
  note: 'Hold my beer!🍺',
  type: 'send',
  time: 1604958667,
  satoshiFees: 113,
  satoshiAmount: 10000,
  fiatExchangeRate: 160.74284545024352,
  fiatCurrencyCode: 'USD',
  participants: [
    {
      type: 'user',
      alias: 'nosetwo',
      displayName: 'Nose two',
      profilePictureUrl: 'https://res.cloudinary.com/hk7jbd3jh/image/upload/v1574787300/gntqxv6ed7sacwpfwumj.jpg',
      responseNote: ''
    }
  ],
  attachments: [ { value: [Object], format: 'json' } ],
}