Tx Builder

tx_builder is a collection of useful functions for instantiating transactions or components of transactions. As opposed to Simple, tx_builder offers more low-level control, and accepts instantiated or components rather than human-readable ones.

riemann.tx.tx_builder.length_prepend(byte_string: bytes) → bytes

Adds a VarInt length marker to a bytestring

riemann.tx.tx_builder.make_decred_input(outpoint: riemann.tx.decred.DecredOutpoint, sequence: int) → riemann.tx.decred.DecredTxIn
riemann.tx.tx_builder.make_decred_witness(value: bytes, height: bytes, index: bytes, stack_script: bytes, redeem_script: bytes) → riemann.tx.decred.DecredInputWitness

Decred has a unique witness structure.

riemann.tx.tx_builder.make_empty_witness() → riemann.tx.tx.InputWitness

Create an InputWitness with an empty stack. Useful for unsigned transactions, as well as Legacy inputs in Segwit transactions. By consensus, if any witness is present, all inputs must have a witness.

riemann.tx.tx_builder.make_legacy_input(outpoint, stack_script, redeem_script, sequence)

Make a legacy input. This supports creating Compatibility inputs by passing the witness program to redeem_script while passing an empty bytestring for stack_script.

Parameters

  • outpoint – The Outpoint object

  • stack_script – A serialized Script program that sets the initial stack

  • redeem_script – A serialized Script program that is run on the stack

  • sequence – The 4-byte LE-encoded sequence number

Returns

A Legacy TxIn object.

riemann.tx.tx_builder.make_op_return_output(data: bytes) → riemann.tx.tx.TxOut

Generates OP_RETURN output for data of up to 77 bytes. OP_RETURN outputs are data carriers with no impact on the UTXO set. They are comonly used to create on-chain commitments to some off-chain information. There are few consensus constraints on their content or structure, however they become non-standard above 77 bytes.

Parameters

data (bytes) – data to be included in output

Returns

TxOut object with OP_RETURN output

Return type

(TxOut)

riemann.tx.tx_builder.make_outpoint(tx_id_le, index, tree=None)

Instantiate an Outpoint object from a transaction id and an index.

Parameters

  • tx_id_le – The 32-byte LE hash of the transaction that created the prevout being referenced.

  • index – The index of the TxOut that created the prevout in its transaction’s output vector

  • tree – Only in Decred transactions. Specifies the commitment tree.

Returns

An Outpoint object. If network is set to Decred, a DecredOutpoint

riemann.tx.tx_builder.make_p2pkh_output(value: int, pubkey: bytes) → riemann.tx.tx.TxOut

Instantiates a P2PKH TxOut from value and raw pubkey.

Parameters

  • value – The 8-byte LE-encoded integer value of the output.

  • pubkey – The 33- or 65-byte raw public key.

Returns

A TxOut object paying a P2PKH script pubkey

riemann.tx.tx_builder.make_p2pkh_output_script(pubkey: bytes) → bytes

Makes a P2PKH script pubkey from a raw public key.

Parameters

pubkey – The 33- or 65-byte public key.

Returns

The P2PKH script pubkey containing the hash of the pubkey.

riemann.tx.tx_builder.make_p2sh_output(value: int, output_script: str) → riemann.tx.tx.TxOut

Instantiates a P2SH TxOut from value and human-readable Script.

Parameters

  • value – The 8-byte LE-encoded integer value of the output.

  • output_script – The non-length-prepended output script.

Returns

A TxOut object paying a P2SH script pubkey.

riemann.tx.tx_builder.make_p2sh_output_script(script_string: str) → bytes

Make a P2SH script pubkey from a human-readable Script.

Parameters

script_string – The human-readable redeem script.

Returns

The P2SH script pubkey containing the hash of the serialized script.

riemann.tx.tx_builder.make_p2wpkh_output(value: int, pubkey: bytes) → riemann.tx.tx.TxOut

Instantiates a P2WPKH TxOut from value and raw pubkey.

Parameters

  • value – The 8-byte LE-encoded integer value of the output.

  • pubkey – The 33- or 65-byte raw public key.

Returns

A TxOut object paying a P2WPKH script pubkey

riemann.tx.tx_builder.make_p2wpkh_output_script(pubkey: bytes) → bytes

Makes a P2PKH or P2WPKH script pubkey from a raw public key. Does not support Compatibility p2wsh-via-p2sh output scripts.

Parameters

pubkey – The 33- or 65-byte public key.

Returns

The P2WPKH script pubkey containing the hash of the pubkey.

riemann.tx.tx_builder.make_p2wsh_output(value: int, output_script: str) → riemann.tx.tx.TxOut

Instantiates a P2WSH TxOut from value and human-readable Script.

Parameters

  • value – The 8-byte LE-encoded integer value of the output.

  • output_script – The non-length-prepended output script.

Returns

A TxOut object paying a P2WSH script pubkey.

riemann.tx.tx_builder.make_p2wsh_output_script(script_string: str) → bytes

Make a P2WSH script pubkey from a human-readable Script. Does not support Compatibility p2wsh-via-p2sh output scripts.

Parameters

script_string – The human-readable witness script.

Returns

The P2WSH script pubkey containing the hash of the serialized script.

riemann.tx.tx_builder.make_pkh_output(value: int, pubkey: bytes, witness: bool = False) → riemann.tx.tx.TxOut

Instantiates a P2PKH or P2WPKH TxOut from value and raw pubkey.

Parameters

  • value – The 8-byte LE-encoded integer value of the output.

  • pubkey – The 33- or 65-byte raw public key.

  • witness – Pass True to make a P2WPKH script pubkey.

Returns

A TxOut object

riemann.tx.tx_builder.make_pkh_output_script(pubkey: bytes, witness: bool = False) → bytes

Makes a P2PKH or P2WPKH script pubkey from a raw public key. Does not support Compatibility p2wpkh-via-p2sh output scripts.

Parameters

  • pubkey – The 33- or 65-byte public key.

  • witness – Pass True to make a P2WSH script pubkey.

Returns

The script pubkey containing the hash of the pubkey.

riemann.tx.tx_builder.make_script_sig(stack_script: str, redeem_script: str) → bytes

Make a serialized script sig from a human-readable stack script and redeem script.

riemann.tx.tx_builder.make_sh_output(value: int, output_script: str, witness: bool = False) → riemann.tx.tx.TxOut

Instantiates a P2SH or P2WSH TxOut from value and human-readable Script.

Parameters

  • value – The 8-byte LE-encoded integer value of the output.

  • output_script – The non-length-prepended human-readable Script.

  • witness – Pass True to make a P2WSH script pubkey.

Returns

A TxOut object

riemann.tx.tx_builder.make_sh_output_script(script_string: str, witness: bool = False) → bytes

Make a P2SH or P2WSH script pubkey from a human-readable script. Does not support Compatibility p2wsh-via-p2sh output scripts.

Parameters

  • script_string – The human-readable redeem script or witness script.

  • witness – Pass True to make a P2WSH script pubkey.

Returns

The script pubkey containing the hash of the serialized script.

riemann.tx.tx_builder.make_sh_script_pubkey(script_bytes: bytes, witness: bool = False) → bytes

Make a P2SH or P2WSH script pubkey from a serialized script. Does not support Compatibility p2wsh-via-p2sh output scripts.

Parameters

  • script_bytes – The serialized redeem script or witness script.

  • witness – Pass True to make a P2WSH script pubkey.

Returns

The script pubkey containing the hash of the serialized script.

riemann.tx.tx_builder.make_tx(version, tx_ins, tx_outs, lock_time, expiry=None, value_balance=0, tx_shielded_spends=None, tx_shielded_outputs=None, tx_witnesses=None, tx_joinsplits=None, joinsplit_pubkey=None, joinsplit_sig=None, binding_sig=None)

Instantiate a complete Tx object from its components.

Parameters

  • version – The 4-byte LE-encoded version number.

  • tx_ins – A list of TxIn objects.

  • tx_outs – A list of TxOut objects.

  • lock_time – The 4-byte LE-encoded lock_time number.

  • expiry – Decred, Overwinter, and Sapling only. 4-byte LE expiry number.

  • value_balance – Sapling only. An 8-byte LE number representing the net change in shielded pool size as a result of this transaction.

  • tx_shielded_spends – Sapling only. An array of SaplingShieldedSpend.

  • tx_shielded_outputs – Sapling only. An array of SaplingShieldedOutput.

  • tx_witnesses – An array of InputWitness objects.

  • tx_joinsplits – Sprout, Overwinter, and Sapling only. An array of SproutJoinsplit or SaplingJoinsplit objects.

  • joinsplit_pubkey – The joinsplit pubkey. See Zcash protocol docs.

  • joinsplit_sig – The joinsplit signature. See Zcash protocol docs.

  • binding_sig – The binding signature. See Zcash protocol docs.

Returns

A Tx object. DecredTx if network is set to Decred. SproutTx if set to Zcash Sprout. OverwinterTx if set to Zcash Overwinter. SaplingTx if set to Zcash Sapling.

riemann.tx.tx_builder.make_witness(data_list: List[bytes]) → riemann.tx.tx.InputWitness

Make a witness stack from a list of bytestrings. Each bytestring is wrapped in a WitnessStackItem object and places into the InputWitness in order

riemann.tx.tx_builder.make_witness_input(outpoint, sequence)

Make a Segwit input. This is clearly superior to make_legacy_input and you should use witness always.

Parameters

  • outpoint – The Outpoint object

  • sequence – The 4-byte LE-encoded sequence number

Returns

A Segwit TxIn object.

riemann.tx.tx_builder.make_witness_stack_item(data: bytes) → riemann.tx.tx.WitnessStackItem

Wrap a bytestring in a WitnessStackItem object