Struct Transaction 

pub struct Transaction {
    pub version: Version,
    pub lock_time: LockTime,
    pub inputs: Vec<TxIn>,
    pub outputs: Vec<TxOut>,
}

Bitcoin transaction.

An authenticated movement of coins.

See Bitcoin Wiki: Transaction for more information.

Bitcoin Core References

• CTransaction definition

Serialization notes

If any inputs have nonempty witnesses, the entire transaction is serialized in the post-BIP-0141 SegWit format which includes a list of witnesses. If all inputs have empty witnesses, the transaction is serialized in the pre-BIP-0141 format.

There is one major exception to this: to avoid deserialization ambiguity, if the transaction has no inputs, it is serialized in the BIP-0141 style. Be aware that this differs from the transaction format in PSBT, which never uses BIP-0141. (Ordinarily there is no conflict, since in PSBT transactions are always unsigned and therefore their inputs have empty witnesses.)

The specific ambiguity is that SegWit uses the flag bytes 0001 where an old serializer would read the number of transaction inputs. The old serializer would interpret this as “no inputs, one output”, which means the transaction is invalid, and simply reject it. SegWit further specifies that this encoding should only be used when some input has a nonempty witness; that is, witness-less transactions should be encoded in the traditional format.

However, in protocols where transactions may legitimately have 0 inputs, e.g. when parties are cooperatively funding a transaction, the “00 means SegWit” heuristic does not work. Since SegWit requires such a transaction to be encoded in the original transaction format (since it has no inputs and therefore no input witnesses), a traditionally encoded transaction may have the 0001 SegWit flag in it, which confuses most SegWit parsers including the one in Bitcoin Core.

We therefore deviate from the spec by always using the SegWit witness encoding for 0-input transactions, which results in unambiguously parseable transactions.

A note on ordering

This type implements Ord, even though it contains a locktime, which is not itself Ord. This was done to simplify applications that may need to hold transactions inside a sorted container. We have ordered the locktimes based on their representation as a u32, which is not a semantically meaningful order, and therefore the ordering on Transaction itself is not semantically meaningful either.

The ordering is, however, consistent with the ordering present in this library before this change, so users should not notice any breakage (here) when transitioning from 0.29 to 0.30.

Fields

version: Version

The protocol version, is currently expected to be 1, 2 (BIP-0068) or 3 (BIP-0431).

lock_time: LockTime

Block height or timestamp. Transaction cannot be included in a block until this height/time.

Relevant BIPs

• BIP-0065 OP_CHECKLOCKTIMEVERIFY
• BIP-0113 Median time-past as endpoint for lock-time calculations

inputs: Vec<TxIn>

List of transaction inputs.

outputs: Vec<TxOut>

List of transaction outputs.

Implementations

impl Transaction

pub const MAX_STANDARD_WEIGHT: Weight

Maximum transaction weight for Bitcoin Core 25.0.

pub fn compute_ntxid(&self) -> Ntxid

Computes a “normalized TXID” which does not include any signatures.

This function is needed only for legacy (pre-Segwit or P2SH-wrapped segwit version 0) applications. This method clears the script_sig field of each input, which in Segwit transactions is already empty, so for Segwit transactions the ntxid will be equal to the txid, and you should simply use the latter.

This gives a way to identify a transaction that is “the same” as another in the sense of having the same inputs and outputs.

pub fn compute_txid(&self) -> Txid

Computes the Txid.

Hashes the transaction excluding the SegWit data (i.e. the marker, flag bytes, and the witness fields themselves). For non-SegWit transactions which do not have any SegWit data, this will be equal to Transaction::compute_wtxid().

pub fn compute_wtxid(&self) -> Wtxid

Computes the SegWit version of the transaction id.

Hashes the transaction including all SegWit data (i.e. the marker, flag bytes, and the witness fields themselves). For non-SegWit transactions which do not have any SegWit data, this will be equal to Transaction::compute_txid().

pub fn is_coinbase(&self) -> bool

Checks if this is a coinbase transaction.

The first transaction in the block distributes the mining reward and is called the coinbase transaction. It is impossible to check if the transaction is first in the block, so this function checks the structure of the transaction instead - the previous output must be all-zeros (creates satoshis “out of thin air”).

Trait Implementations

impl<'a> Arbitrary<'a> for Transaction

Available on crate features arbitrary and alloc only.

fn arbitrary(u: &mut Unstructured<'a>) -> Result<Self>

Generate an arbitrary value of Self from the given unstructured data.

fn arbitrary_take_rest(u: Unstructured<'a>) -> Result<Self, Error>

Generate an arbitrary value of Self from the entirety of the given unstructured data.

fn size_hint(depth: usize) -> (usize, Option<usize>)

Get a size hint for how many bytes out of an Unstructured this type needs to construct itself.

fn try_size_hint( depth: usize, ) -> Result<(usize, Option<usize>), MaxRecursionReached>

Get a size hint for how many bytes out of an Unstructured this type needs to construct itself.

impl Clone for Transaction

fn clone(&self) -> Transaction

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Transaction

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Decodable for Transaction

Available on crate feature alloc only.

type Decoder = TransactionDecoder

Associated decoder for the type.

fn decoder() -> Self::Decoder

Constructs a “default decoder” for the type.

impl Display for Transaction

Available on crate features hex and alloc only.

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Encodable for Transaction

Available on crate feature alloc only.

type Encoder<'e> = TransactionEncoder<'e> where Self: 'e

The encoder associated with this type. Conceptually, the encoder is like an iterator which yields byte slices.

fn encoder(&self) -> Self::Encoder<'_>

Constructs a “default encoder” for the type.

impl From<&Transaction> for Txid

Available on crate feature alloc only.

fn from(tx: &Transaction) -> Self

Converts to this type from the input type.

impl From<&Transaction> for Wtxid

Available on crate feature alloc only.

fn from(tx: &Transaction) -> Self

Converts to this type from the input type.

impl From<Transaction> for Txid

Available on crate feature alloc only.

fn from(tx: Transaction) -> Self

Converts to this type from the input type.

impl From<Transaction> for Wtxid

Available on crate feature alloc only.

fn from(tx: Transaction) -> Self

Converts to this type from the input type.

impl FromStr for Transaction

Available on crate features hex and alloc only.

type Err = ParseTransactionError

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Self, Self::Err>

Parses a string s to return a value of this type.

impl Hash for Transaction

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl LowerHex for Transaction

Available on crate features hex and alloc only.

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Ord for Transaction

Available on crate feature alloc only.

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for Transaction

fn eq(&self, other: &Transaction) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for Transaction

Available on crate feature alloc only.

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl UpperHex for Transaction

Available on crate features hex and alloc only.

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for Transaction

impl StructuralPartialEq for Transaction