[v11.0.0] New Transaction Composer

counterparty-core/counterpartycore/lib/backend/bitcoind.py

@@ -182,6 +182,17 @@ def fee_per_kb(
     return int(max(feeperkb["feerate"] * config.UNIT, config.DEFAULT_FEE_PER_KB_ESTIMATE_SMART))
 
 
+def satoshis_per_vbyte(
+    conf_target: int = config.ESTIMATE_FEE_CONF_TARGET, mode: str = config.ESTIMATE_FEE_MODE
+):
+    feeperkb = rpc("estimatesmartfee", [conf_target, mode])
+
+    if "errors" in feeperkb and feeperkb["errors"][0] == "Insufficient data or no feerate found":
+        return config.DEFAULT_FEE_PER_KB_ESTIMATE_SMART
+
+    return (feeperkb["feerate"] * config.UNIT) / 1024
+
+
 def get_btc_supply(normalize=False):
     f"""returns the total supply of {config.BTC} (based on what Bitcoin Core says the current block height is)"""  # noqa: B021
     block_count = getblockcount()
@@ -277,6 +288,10 @@ def get_tx_out_amount(tx_hash, vout):
     return raw_tx["vout"][vout]["value"]
 
 
+def get_tx_out_value(tx_hash, vout):
+    return get_tx_out_amount(tx_hash, vout)
+
+
 class BlockFetcher:
     def __init__(self, first_block) -> None:
         self.current_block = first_block

counterparty-core/counterpartycore/lib/composer.py

@@ -0,0 +1,250 @@
+import binascii
+
+from bitcoin.core.script import (
+    OP_CHECKMULTISIG,
+    OP_RETURN,
+    CScript,
+    CTransaction,
+    CTxIn,
+    CTxOut,
+)
+from bitcoin.wallet import CBitcoinAddress, P2WPKHBitcoinAddress
+
+from counterpartycore.lib import arc4, backend, config, exceptions, script, transaction, util
+from counterpartycore.lib.transaction_helper.common_serializer import make_fully_valid
+from counterpartycore.lib.transaction_helper.transaction_outputs import chunks
+
+MAX_INPUTS_SET = 100
+
+
+def get_script(address):
+    if script.is_multisig(address):
+        signatures_required, pubkeys, signatures_possible = script.extract_array(address)
+        return CScript([signatures_required] + pubkeys + [signatures_possible, OP_CHECKMULTISIG])
+    elif script.is_bech32(address):
+        return P2WPKHBitcoinAddress(address).to_scriptPubKey()
+    else:
+        return CBitcoinAddress(address).to_scriptPubKey()
+
+
+def get_default_value(address):
+    if script.is_multisig(address):
+        return config.MULTISIG_DUST_SIZE
+    else:
+        return config.REGULAR_DUST_SIZE
+
+
+def perpare_non_data_outputs(destinations):
+    outputs = []
+    for address, value in destinations:
+        output_value = value or get_default_value(address)
+        outputs.append(CTxOut(output_value, get_script(address)))
+    return outputs
+
+
+def determine_encoding(data, desired_encoding="auto"):
+    encoding = desired_encoding
+    if desired_encoding == "auto":
+        if len(data) + len(config.PREFIX) <= config.OP_RETURN_MAX_SIZE:
+            encoding = "opreturn"
+        else:
+            encoding = "multisig"
+    if encoding not in ("multisig", "opreturn"):
+        raise exceptions.TransactionError(f"Not supported encoding: {encoding}")
+    return encoding
+
+
+def encrypt_data(data, arc4_key):
+    key = arc4.init_arc4(binascii.unhexlify(arc4_key))
+    return key.encrypt(data)
+
+
+def prepare_opreturn_output(data, arc4_key=None):
+    if len(data) + len(config.PREFIX) > config.OP_RETURN_MAX_SIZE:
+        raise exceptions.TransactionError("One `OP_RETURN` output per transaction.")
+    opreturn_data = config.PREFIX + data
+    if arc4_key:
+        opreturn_data = encrypt_data.encrypt(opreturn_data, arc4_key)
+    return [CTxOut(0, CScript([OP_RETURN, opreturn_data]))]
+
+
+def data_to_pubkey_pairs(data, arc4_key=None):
+    # Two pubkeys, minus length byte, minus prefix, minus two nonces,
+    # minus two sign bytes.
+    chunk_size = (33 * 2) - 1 - len(config.PREFIX) - 2 - 2
+    data_array = list(chunks(data, chunk_size))
+    pubkey_pairs = []
+    for data_chunk in data_array:
+        # Get data (fake) public key.
+        pad_length = (33 * 2) - 1 - 2 - 2 - len(data_chunk)
+        assert pad_length >= 0
+        output_data = bytes([len(data_chunk)]) + data_chunk + (pad_length * b"\x00")  # noqa: PLW2901
+        if arc4_key:
+            output_data = encrypt_data(output_data, arc4_key)
+        data_pubkey_1 = make_fully_valid(output_data[:31])
+        data_pubkey_2 = make_fully_valid(output_data[31:])
+        pubkey_pairs.append((data_pubkey_1, data_pubkey_2))
+    return pubkey_pairs
+
+
+def prepare_multisig_output(data, pubkey, arc4_key=None):
+    try:
+        dust_return_pubkey = binascii.unhexlify(pubkey)
+    except binascii.Error:
+        raise script.InputError(f"Invalid pubkey key: {pubkey}")  # noqa: B904
+    if not script.is_fully_valid(dust_return_pubkey):
+        raise exceptions.ComposeError(f"invalid public key: {pubkey}")
+    pubkey_pairs = data_to_pubkey_pairs(data, arc4_key)
+    outputs = []
+    for pubkey_pair in pubkey_pairs:
+        output_script = CScript(
+            [1, pubkey_pair[0], pubkey_pair[1], dust_return_pubkey, 3, OP_CHECKMULTISIG]
+        )
+        outputs.append(CTxOut(config.MULTISIG_DUST_SIZE, output_script))
+    return outputs
+
+
+def prepare_data_outputs(encoding, data, source, pubkey, arc4_key=None):
+    data_encoding = determine_encoding(data, encoding)
+    if data_encoding == "multisig":
+        return prepare_multisig_output(data, source, pubkey, arc4_key)
+    if data_encoding == "opreturn":
+        return prepare_opreturn_output(data, arc4_key)
+    raise exceptions.TransactionError(f"Not supported encoding: {encoding}")
+
+
+def prepare_outputs(source, destinations, data, pubkey, encoding, arc4_key=None):
+    outputs = perpare_non_data_outputs(destinations)
+    if data:
+        outputs += prepare_data_outputs(encoding, data, source, pubkey, arc4_key)
+    return outputs
+
+
+def prepare_unspent_list(inputs_set: str):
+    unspent_list = []
+    utxos_list = inputs_set.split(",")
+    if len(utxos_list) > MAX_INPUTS_SET:
+        raise exceptions.ComposeError(
+            f"too many UTXOs in inputs_set (max. {MAX_INPUTS_SET}): {len(utxos_list)}"
+        )
+    for str_input in utxos_list:
+        if not util.is_utxo_format(str_input):
+            raise exceptions.ComposeError(f"invalid UTXO: {str_input}")
+        try:
+            value = backend.bitcoind.get_tx_out_value(
+                str_input.split(":")[0], int(str_input.split(":")[1])
+            )
+        except Exception as e:
+            raise exceptions.ComposeError(f"invalid UTXO: {str_input}") from e
+        unspent_list.append(
+            {
+                "txid": str_input.split(":")[0],
+                "vout": int(str_input.split(":")[1]),
+                "value": value,
+            }
+        )
+    return sorted(unspent_list, key=lambda x: x["value"], reverse=True)
+
+
+def select_utxos(unspent_list, target_amount):
+    total_amount = 0
+    selected_utxos = []
+    for utxo in unspent_list:
+        total_amount += utxo["value"]
+        selected_utxos.append(utxo)
+        if total_amount >= target_amount:
+            break
+    return selected_utxos
+
+
+def utxos_to_txins(utxos: list):
+    inputs = []
+    for utxo in utxos:
+        inputs.append(CTxIn(CScript([utxo["txid"], utxo["vout"]])))
+    return inputs
+
+
+def get_virtual_size(weight):
+    return (weight + 3) // 4
+
+
+def get_needed_fee(tx, satoshis_per_vbyte=None):
+    weight = tx.calc_weight()
+    virtual_size = get_virtual_size(weight)
+    if satoshis_per_vbyte:
+        return satoshis_per_vbyte * virtual_size
+    else:
+        return backend.bitcoind.satoshis_per_vbyte() * virtual_size
+
+
+def get_minimum_change(source):
+    if script.is_multisig(source):
+        return config.MULTISIG_DUST_SIZE
+    else:
+        return config.REGULAR_DUST_SIZE
+
+
+def prepare_transaction(source, outputs, unspent_list, desired_fee):
+    outputs_total = sum(output["value"] for output in outputs)
+    target_amount = outputs_total + desired_fee
+    selected_utxos = select_utxos(unspent_list, target_amount)
+    input_total = sum(input["value"] for input in selected_utxos)
+    inputs = utxos_to_txins(selected_utxos)
+    change = input_total - target_amount
+    change_outputs = []
+    if change > get_minimum_change(source):
+        change_outputs.append(CTxOut(change, get_script(source)))
+    else:
+        change = 0
+    return inputs, change_outputs, input_total
+
+
+def construct_transaction(source, outputs, unspent_list, desired_fee):
+    inputs, change_outputs, _input_total = prepare_transaction(
+        source, outputs, unspent_list, desired_fee
+    )
+    tx = CTransaction(inputs, outputs + change_outputs)
+    return tx
+
+
+def get_estimated_fee(source, outputs, unspent_list, satoshis_per_vbyte=None):
+    # calculate fee for a transaction with desired_fee = 0
+    tx = construct_transaction(source, outputs, unspent_list, 0)
+    return get_needed_fee(tx, satoshis_per_vbyte)
+
+
+def compose_transaction(
+    db, name, params, pubkey, inputs_set, encoding="auto", exact_fee=None, satoshis_per_vbyte=None
+):
+    source, destinations, data = transaction.compose_data(db, name, params)
+    unspent_list = prepare_unspent_list(inputs_set)
+
+    # prepare non obfuscted outputs
+    clear_outputs = prepare_outputs(source, destinations, data, pubkey, encoding)
+
+    if exact_fee:
+        desired_fee = exact_fee
+    else:
+        # use non obfuscated outputs to calculate estimated fee...
+        desired_fee = get_estimated_fee(source, clear_outputs, unspent_list, satoshis_per_vbyte)
+
+    # prepare transaction with desired fee and no-obfuscated outputs
+    inputs, change_outputs, btc_in = prepare_transaction(
+        source, clear_outputs, unspent_list, desired_fee
+    )
+    # now we have inputs we can prepare obfuscated outputs
+    outputs = prepare_outputs(
+        source, destinations, data, pubkey, encoding, arc4_key=inputs[0]["txid"]
+    )
+    tx = CTransaction(inputs, outputs + change_outputs)
+    btc_out = sum(output.nValue for output in outputs)
+    btc_change = sum(change_output.nValue for change_output in change_outputs)
+
+    return {
+        "btc_in": btc_in,
+        "btc_out": btc_out,
+        "btc_change": btc_change,
+        "btc_fee": btc_in - btc_out - btc_change,
+        "unsigned_tx_hex": tx.serialize().hex(),
+        "data": config.PREFIX + data if data else None,
+    }