helpful-tips.md

Helpful Tips

For detailed information on the Bitcoin Cash specification, check out reference.cash.

Determining a Cash Address from an input

Chaingraph provides access to direct Blockchain information with some indexing and help, but many use cases will require further user friendly wrapping. For instance, the GraphQL schema provides access to an input's locking_bytecode, but not the corresponding CashAddress. See Reference.cash for more about locking scripts.

Example GraphQl call fetching information for transaction 7b1f7a00736c7d4ae0b011fa9544e5fd36a71bf139f9c57920f7f8e6d54a578e (transaction on Blockchair.com). Note the \\x prefix required by the GraphQL API.

Try it yourself at try.chaingraph.cash.

query GetTransactionDetails {
  transaction(
    where: {
      hash: {
        _eq: "\\x7b1f7a00736c7d4ae0b011fa9544e5fd36a71bf139f9c57920f7f8e6d54a578e"
      }
    }
  ) {
    hash
    inputs {
      outpoint {
        locking_bytecode
      }
    }
  }
}

Returns:

{
  "data": {
    "transaction": [
      {
        "hash": "\\x7b1f7a00736c7d4ae0b011fa9544e5fd36a71bf139f9c57920f7f8e6d54a578e",
        "inputs": [
          {
            "outpoint": {
              "locking_bytecode": "\\x76a914c3b6a8a716bc001eda8a31ec04954a4b5c86a42b88ac"
            }
          },
          {
            "outpoint": {
              "locking_bytecode": "\\x76a914b03c4b800bb0575f6c0f11e155541cc0661a8f9a88ac"
            }
          }
        ]
      }
    ]
  }
}

The locking_bytecode from each input can then be be translated to a CashAddress using libauth.

import libauth from "@bitauth/libauth"

// Note again, exclusion of `\\x` prefix
const input1LockingBytecode = "76a914c3b6a8a716bc001eda8a31ec04954a4b5c86a42b88ac";
libauth.lockingBytecodeToCashAddress(
  libauth.hexToBin(input1LockingBytecode),
  "bitcoincash"
);
// 'bitcoincash:qrpmd298z67qq8k63gc7cpy4ff94ep4y9vrlux4dc4'

const input2LockingBytecode = "76a914b03c4b800bb0575f6c0f11e155541cc0661a8f9a88ac";
libauth.lockingBytecodeToCashAddress(
  libauth.hexToBin("76a914b03c4b800bb0575f6c0f11e155541cc0661a8f9a88ac"),
  "bitcoincash"
);
// 'bitcoincash:qzcrcjuqpwc9whmvpug7z425rnqxvx50ngl60rrjst'

// Legacy address format
const sha256 = await libauth.instantiateSha256();
const legacyAddress = libauth.lockingBytecodeToBase58Address(
  sha256,
  libauth.hexToBin(input2LockingBytecode),
  "mainnet"
);
// '1H4rA8McqZxJ83pJV4w9arE8SFaort8vo8'