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Transaction Module

Build and serialize Hoosat transactions.

Overview​

The transaction.mo module provides low-level transaction building and serialization.

Core Functions​

buildTransaction​

Build a Hoosat transaction with one input and 1-2 outputs.

public func buildTransaction(
  utxo: UTXO,
  recipientScript: Text,
  outputAmount: Nat64,
  fee: Nat64,
  changeScript: Text
) : HoosatTransaction

Parameters:

  • utxo: UTXO to spend
  • recipientScript: Recipient's script public key (hex)
  • outputAmount: Amount to send in sompi
  • fee: Transaction fee in sompi
  • changeScript: Change address script public key (hex)

Example:

import Transaction "mo:hoosat-mo/transaction";
import Types "mo:hoosat-mo/types";

let utxo : Types.UTXO = {
  transactionId = "a1b2c3...";
  index = 0;
  amount = 2000000;
  scriptVersion = 0;
  scriptPublicKey = "20a1b2c3...ac";
  address = "hoosat:qp...";
};

let tx = Transaction.buildTransaction(
  utxo,
  "20d4e5f6...ac",    // Recipient script
  1000000,            // 0.01 HTN
  1000,               // 0.00001 HTN fee
  "20a1b2c3...ac"     // Change script
);

serializeTransaction​

Serialize transaction to JSON for broadcasting.

public func serializeTransaction(
  tx: HoosatTransaction
) : Text

Example:

let json = Transaction.serializeTransaction(tx);
// Returns: "{\"transaction\":{\"version\":0,\"inputs\":[...]}}"

Utility Functions​

signatureToHex​

Convert signature to hex string.

public func signatureToHex(
  sig: [Nat8]
) : Text

arrayFromHex​

Convert hex string to byte array.

public func arrayFromHex(
  hex: Text
) : [Nat8]

Transaction Structure​

public type HoosatTransaction = {
  version: Nat16;
  inputs: [TransactionInput];
  outputs: [TransactionOutput];
  lockTime: Nat64;
  subnetworkId: Text;
  gas: Nat64;
  payload: Text;
};

Constants​

Transaction.DUST_THRESHOLD  // 1,000 sompi
Transaction.DEFAULT_VERSION // 0