CAT721

@opcat-labs/cat-sdk v1.0.3

---

@opcat-labs/cat-sdk / CAT721

Class: CAT721

Defined in: packages/cat-sdk/src/contracts/cat721/cat721.ts:16

The CAT721 contract

Onchain

Extends

• SmartContract\<CAT721State>

Constructors

new CAT721()

new CAT721(minterScriptHash, guardScriptHash): CAT721

Defined in: packages/cat-sdk/src/contracts/cat721/cat721.ts:24

Parameters

minterScriptHash

ByteString

guardScriptHash

ByteString

Returns

CAT721

Overrides

SmartContract<CAT721State>.constructor

Backtrace

backtraceToOutpoint()

backtraceToOutpoint(backtraceInfo, genesisOutpoint): boolean

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:283

Check whether the contract can be traced back to the genesis outpoint.

Parameters

backtraceInfo

BacktraceInfo

the backtrace info to verify, including prevTx and prevPrevTx informations

genesisOutpoint

ByteString

expected genesis outpoint to be traced back to

Returns

boolean

true if the contract can be backtraced to the genesis outpoint. Otherwise false.

Onchain

Inherited from

SmartContract.backtraceToOutpoint

---

backtraceToScript()

backtraceToScript(backtraceInfo, genesisScript): boolean

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:292

Check whether the contract can be traced back to the genesis script.

Parameters

backtraceInfo

BacktraceInfo

the backtrace info to verify, including prevTx and prevPrevTx informations

genesisScript

ByteString

expected genesis script to be traced back to

Returns

boolean

true if the contract can be backtraced to the genesis script. Otherwise false.

Onchain

Inherited from

SmartContract.backtraceToScript

Other

_state

_state: CAT721State

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:50

The state of the contract UTXO, usually committed to the first OP_RETURN output, is revealed when spending.

Onchain

Inherited from

SmartContract._state

---

guardScriptHash

guardScriptHash: ByteString

Defined in: packages/cat-sdk/src/contracts/cat721/cat721.ts:22

---

lockingScript

readonly lockingScript: Script

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:56

Locking script corresponding to the SmartContract

Inherited from

SmartContract.lockingScript

---

minterScriptHash

minterScriptHash: ByteString

Defined in: packages/cat-sdk/src/contracts/cat721/cat721.ts:19

---

utxo?

optional utxo: ExtUtxo

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:45

Inherited from

SmartContract.utxo

---

artifact

static artifact: Artifact

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:33

Bitcoin Contract Artifact

Inherited from

SmartContract.artifact

---

changeInfo

Get Signature

get changeInfo(): TxOut

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:226

Get the change info of the change output for current psbt.

Onchain

Returns

TxOut

the change info of current psbt

Inherited from

SmartContract.changeInfo

---

ctx

Get Signature

get ctx(): IContext

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:171

Get the context details of the current PSBT input in which this contract is called or spent.

Onchain

Returns

IContext

Inherited from

SmartContract.ctx

---

debug

Get Signature

get debug(): object

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:231

A set of functions for debugging contracts, which can only be called in @method methods.

Onchain

Returns

object

diffOutputs()

diffOutputs: (outputsByte) => void

Parameters

outputsByte

ByteString

Returns

void

Inherited from

SmartContract.debug

---

inputContext

Get Signature

get inputContext(): InputContext

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:192

Get the context of the current PSBT input in which this contract is called or spent.

Returns

InputContext

the context of the current PSBT input

Inherited from

SmartContract.inputContext

---

lockingScriptHash

Get Signature

get lockingScriptHash(): Sha256

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:57

Returns

Sha256

Inherited from

SmartContract.lockingScriptHash

---

spentPsbt

Get Signature

get spentPsbt(): undefined | Contextual

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:182

Gets the PSBT (Partially Signed Bitcoin Transaction) that was used to spend this contract. Returns undefined if no spending transaction exists.

Returns

undefined | Contextual

Inherited from

SmartContract.spentPsbt

---

state

Get Signature

get state(): StateT

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:51

Returns

StateT

Set Signature

set state(state): void

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:52

Parameters

state

StateT

Returns

void

Inherited from

SmartContract.state

---

asyncBindToUtxo()

asyncBindToUtxo(utxo, callback): Promise\<CAT721>

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:306

Parameters

utxo

Optional\<ExtUtxo, "script"> | Optional\<UTXO, "script">

callback

(contract) => Promise\<void>

Returns

Promise\<CAT721>

Inherited from

SmartContract.asyncBindToUtxo

---

bindToUtxo()

bindToUtxo(utxo): this

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:305

Binds the smart contract to a UTXO by verifying and setting its script.

Parameters

utxo

The UTXO to bind to (script field is optional)

Optional\<ExtUtxo, "script"> | Optional\<UTXO, "script">

Returns

this

The contract instance for chaining

Throws

Error if the UTXO's script exists and doesn't match the contract's locking script

Inherited from

SmartContract.bindToUtxo

---

buildChangeOutput()

buildChangeOutput(): ByteString

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:112

A built-in function to create an [change output][https://en.bitcoin.it/wiki/Change](https://en.bitcoin.it/wiki/Change).

Returns

ByteString

Onchain

Inherited from

SmartContract.buildChangeOutput

---

checkGuard()

checkGuard(guardState, t_cat721ScriptHash, t_cat721InputIndex, guardInputIndex, t_spentScriptsCtx, t_spentDataHashesCtx): void

Defined in: packages/cat-sdk/src/contracts/cat721/cat721.ts:61

Parameters

guardState

CAT721GuardConstState

t_cat721ScriptHash

ByteString

t_cat721InputIndex

bigint

guardInputIndex

bigint

t_spentScriptsCtx

ByteString

t_spentDataHashesCtx

ByteString

Returns

void

---

checkInputState()

checkInputState(inputIndex, serializedState): boolean

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:158

check state of the input. option in the @method() decorator to false.

Parameters

inputIndex

Int32

index of the input

serializedState

ByteString

the state of the input

Returns

boolean

success if stateHash is valid

Onchain

Inherited from

SmartContract.checkInputState

---

checkOutputs()

checkOutputs(outputs): boolean

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:240

Check the outputs with the context of current transaction.

Parameters

outputs

ByteString

the expected serialized outputs of the current transaction

Returns

boolean

true if the outputs are not consistent with the transaction context, otherwise false.

Onchain

Inherited from

SmartContract.checkOutputs

---

checkSHPreimage()

checkSHPreimage(shPreimage): boolean

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:85

Using the [OP_PUSH_TX][https://medium.com/@xiaohuiliu/op-push-tx-3d3d279174c1](https://medium.com/@xiaohuiliu/op-push-tx-3d3d279174c1) technique, check if shPreimage is the preimage of the current transaction.

Parameters

shPreimage

SHPreimage

Returns

boolean

true if shPreimage is the preimage of the current transaction. Otherwise false.

Onchain

Inherited from

SmartContract.checkSHPreimage

---

getCallData()

getCallData(): MethodCallData

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:251

Gets the method call data for the current smart contract.

Returns

MethodCallData

The method call data object.

Throws

If no method call is found.

Inherited from

SmartContract.getCallData

---

getUnlockingScript()

getUnlockingScript(): Script

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:245

Returns the raw arguments from the call data of the smart contract.

Returns

Script

The raw arguments extracted from the call data.

Inherited from

SmartContract.getUnlockingScript

---

isPubFunction()

isPubFunction(method): boolean

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:210

Checks if the given method is a public function in the smart contract.

Parameters

method

string

The method name to check.

Returns

boolean

True if the method is a public function, false otherwise.

Inherited from

SmartContract.isPubFunction

---

next()

next(newState): this

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:298

Get a new contract instance with the new state.

Parameters

newState

CAT721State

the new state

Returns

this

the new covenant

Inherited from

SmartContract.next

---

setSighashType()

setSighashType(sigHashType): void

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:187

Sets the signature hash type for the current input in the PSBT.

Parameters

sigHashType

SigHashType

The signature hash type to set

Returns

void

Inherited from

SmartContract.setSighashType

---

spentFromInput()

spentFromInput(psbt, inputIndex): void

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:177

Mark the contract instance as spent from the input of the PSBT.

Parameters

psbt

Contextual

inputIndex

number

Returns

void

Inherited from

SmartContract.spentFromInput

---

timeLock()

timeLock(nLockTime): boolean

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:274

Checks a locktime parameter with the transaction's locktime. There are two times of nLockTime: lock-by-blockheight and lock-by-blocktime, distinguished by whether nLockTime < LOCKTIME_THRESHOLD = 500000000

See the corresponding code on bitcoin core: https://github.com/bitcoin/bitcoin/blob/ffd75adce01a78b3461b3ff05bcc2b530a9ce994/src/script/interpreter.cpp#L1129

See the bip65 for specification https://github.com/bitcoin/bips/blob/master/bip-0065.mediawiki#summary

Parameters

nLockTime

Int32

the locktime read from the script

Returns

boolean

true if the transaction's locktime is less than or equal to the transaction's locktime

Onchain

Inherited from

SmartContract.timeLock

---

unlock()

unlock(unlockArgs, guardState, guardInputIndex, backtraceInfo): void

Defined in: packages/cat-sdk/src/contracts/cat721/cat721.ts:31

Parameters

unlockArgs

ContractUnlockArgs

guardState

CAT721GuardConstState

guardInputIndex

bigint

backtraceInfo

BacktraceInfo

Returns

void

---

create()

static create\<T>(this, ...args): InstanceType\<T>

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:76

Used to create an instance of a smart contract. If your smart contract has a base class, you must use this method to instantiate it.

Type Parameters

• T extends (...args) => InstanceType\<T>

Parameters

this

T

args

...ConstructorParameters\<T>

Returns

InstanceType\<T>

Inherited from

SmartContract.create

---

deserializeState()

static deserializeState\<T>(this, serializedState): T

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:136

Deserializes the contract state from a ByteString.

Type Parameters

• T extends OpcatState

The type of the contract state extending OpcatState

Parameters

this

(...args) => SmartContract\<T>

serializedState

ByteString

The serialized state as a ByteString

Returns

T

The deserialized state object of type T

Throws

Error if artifact is not loaded or state type is not defined

Inherited from

SmartContract.deserializeState

---

isStateful()

static isStateful(): boolean

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:311

Checks if the contract has state by verifying if the state object exists and is not empty.

Returns

boolean

True if the contract has state, false otherwise.

Inherited from

SmartContract.isStateful

---

loadArtifact()

static loadArtifact(artifact): typeof SmartContract

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:63

This function is usually called on the frontend. The contract class needs to call this function before instantiating.

Parameters

artifact

Artifact

a contract artifact json object

Returns

typeof SmartContract

Inherited from

SmartContract.loadArtifact

---

serializeState()

static serializeState\<T>(this, state): ByteString

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:126

Serializes the contract state into a ByteString.

Type Parameters

• T extends OpcatState

Type of the contract state extending OpcatState

Parameters

this

(...args) => SmartContract\<T>

Constructor reference for type inference

state

T

The contract state object to serialize

Returns

ByteString

Serialized state as ByteString

Throws

Error if artifact is not loaded or state type is not defined

Inherited from

SmartContract.serializeState

---

stateHash()

static stateHash\<T>(this, state): ByteString

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:147

Computes the SHA-256 hash of the serialized contract state.

Type Parameters

• T extends OpcatState

Type extending OpcatState

Parameters

this

(...args) => SmartContract\<T>

state

T

The contract state to hash

Returns

ByteString

ByteString containing the SHA-256 hash of the serialized state

Inherited from

SmartContract.stateHash

Signature Verification

checkMultiSig()

checkMultiSig(signatures, publickeys): boolean

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:106

Compares the first signature against each public key until it finds an ECDSA match. Starting with the subsequent public key, it compares the second signature against each remaining public key until it finds an ECDSA match. The process is repeated until all signatures have been checked or not enough public keys remain to produce a successful result. All signatures need to match a public key. Because public keys are not checked again if they fail any signature comparison, signatures must be placed in the scriptSig using the same order as their corresponding public keys were placed in the scriptPubKey or redeemScript. If all signatures are valid, 1 is returned, 0 otherwise. Due to a bug, one extra unused value is removed from the stack.

Parameters

signatures

Sig[]

publickeys

PubKey[]

Returns

boolean

Onchain

Inherited from

SmartContract.checkMultiSig

---

checkSig()

checkSig(signature, publickey, errorMsg?): boolean

Defined in: node_modules/@opcat-labs/scrypt-ts-opcat/dist/types/smart-contract/smartContract.d.ts:92

A built-in function verifies an Schnorr signature. It takes two inputs from the stack, a public key (on top of the stack) and an Schnorr signature in its DER_CANONISED format concatenated with sighash flags. It outputs true or false on the stack based on whether the signature check passes or fails. [see][https://github.com/bitcoin/bips/blob/master/bip-0341.mediawiki#specification](https://github.com/bitcoin/bips/blob/master/bip-0341.mediawiki#specification)

Parameters

signature

Sig

publickey

PubKey

errorMsg?

string

Returns

boolean

Onchain

Inherited from

SmartContract.checkSig