194933a5cc
Unfortunately Go doesn't allow to easily reuse readers in full packages, still we can have this wrapper with a little overhead (the alternative is to move specific methods into types of their own, but I'm not sure how it's going to be accepted user-side).
247 lines
9.2 KiB
Go
247 lines
9.2 KiB
Go
/*
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Package nep11 contains RPC wrappers for NEP-11 contracts.
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The set of types provided is split between common NEP-11 methods (BaseReader and
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Base types) and divisible (DivisibleReader and Divisible) and non-divisible
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(NonDivisibleReader and NonDivisible). If you don't know the type of NEP-11
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contract you're going to use you can use Base and BaseReader types for many
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purposes, otherwise more specific types are recommended.
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*/
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package nep11
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import (
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"fmt"
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"math/big"
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"unicode/utf8"
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"github.com/google/uuid"
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"github.com/nspcc-dev/neo-go/pkg/core/transaction"
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"github.com/nspcc-dev/neo-go/pkg/neorpc/result"
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"github.com/nspcc-dev/neo-go/pkg/rpcclient/neptoken"
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"github.com/nspcc-dev/neo-go/pkg/rpcclient/unwrap"
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"github.com/nspcc-dev/neo-go/pkg/smartcontract"
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"github.com/nspcc-dev/neo-go/pkg/util"
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"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
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)
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// Invoker is used by reader types to call various methods.
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type Invoker interface {
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neptoken.Invoker
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CallAndExpandIterator(contract util.Uint160, method string, maxItems int, params ...interface{}) (*result.Invoke, error)
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TerminateSession(sessionID uuid.UUID) error
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TraverseIterator(sessionID uuid.UUID, iterator *result.Iterator, num int) ([]stackitem.Item, error)
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}
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// Actor is used by complete NEP-11 types to create and send transactions.
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type Actor interface {
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Invoker
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MakeRun(script []byte) (*transaction.Transaction, error)
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MakeUnsignedRun(script []byte, attrs []transaction.Attribute) (*transaction.Transaction, error)
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SendRun(script []byte) (util.Uint256, uint32, error)
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}
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// BaseReader is a reader interface for common divisible and non-divisible NEP-11
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// methods. It allows to invoke safe methods.
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type BaseReader struct {
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neptoken.Base
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invoker Invoker
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hash util.Uint160
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}
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// Base is a state-changing interface for common divisible and non-divisible NEP-11
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// methods.
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type Base struct {
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BaseReader
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actor Actor
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}
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// TransferEvent represents a Transfer event as defined in the NEP-11 standard.
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type TransferEvent struct {
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From util.Uint160
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To util.Uint160
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Amount *big.Int
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ID []byte
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}
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// TokenIterator is used for iterating over TokensOf results.
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type TokenIterator struct {
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client Invoker
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session uuid.UUID
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iterator result.Iterator
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}
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// NewBaseReader creates an instance of BaseReader for a contract with the given
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// hash using the given invoker.
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func NewBaseReader(invoker Invoker, hash util.Uint160) *BaseReader {
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return &BaseReader{*neptoken.New(invoker, hash), invoker, hash}
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}
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// NewBase creates an instance of Base for contract with the given
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// hash using the given actor.
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func NewBase(actor Actor, hash util.Uint160) *Base {
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return &Base{*NewBaseReader(actor, hash), actor}
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}
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// BalanceOf returns the number of NFTs owned by the given account. For divisible
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// NFTs that's the sum of all parts of tokens.
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func (t *BaseReader) BalanceOf(account util.Uint160) (*big.Int, error) {
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return unwrap.BigInt(t.invoker.Call(t.hash, "balanceOf", account))
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}
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// Properties returns a set of token's properties such as name or URL. The map
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// is returned as is from this method (stack item) for maximum flexibility,
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// contracts can return a lot of specific data there. Most of the time though
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// they return well-defined properties outlined in NEP-11 and
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// UnwrapKnownProperties can be used to get them in more convenient way. It's an
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// optional method per NEP-11 specification, so it can fail.
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func (t *BaseReader) Properties(token []byte) (*stackitem.Map, error) {
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return unwrap.Map(t.invoker.Call(t.hash, "properties", token))
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}
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// Tokens returns an iterator that allows to retrieve all tokens minted by the
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// contract. It depends on the server to provide proper session-based
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// iterator, but can also work with expanded one. The method itself is optional
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// per NEP-11 specification, so it can fail.
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func (t *BaseReader) Tokens() (*TokenIterator, error) {
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sess, iter, err := unwrap.SessionIterator(t.invoker.Call(t.hash, "tokens"))
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if err != nil {
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return nil, err
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}
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return &TokenIterator{t.invoker, sess, iter}, nil
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}
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// TokensExpanded uses the same NEP-11 method as Tokens, but can be useful if
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// the server used doesn't support sessions and doesn't expand iterators. It
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// creates a script that will get num of result items from the iterator right in
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// the VM and return them to you. It's only limited by VM stack and GAS available
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// for RPC invocations.
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func (t *BaseReader) TokensExpanded(num int) ([][]byte, error) {
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return unwrap.ArrayOfBytes(t.invoker.CallAndExpandIterator(t.hash, "tokens", num))
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}
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// TokensOf returns an iterator that allows to walk through all tokens owned by
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// the given account. It depends on the server to provide proper session-based
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// iterator, but can also work with expanded one.
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func (t *BaseReader) TokensOf(account util.Uint160) (*TokenIterator, error) {
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sess, iter, err := unwrap.SessionIterator(t.invoker.Call(t.hash, "tokensOf", account))
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if err != nil {
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return nil, err
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}
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return &TokenIterator{t.invoker, sess, iter}, nil
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}
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// TokensOfExpanded uses the same NEP-11 method as TokensOf, but can be useful if
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// the server used doesn't support sessions and doesn't expand iterators. It
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// creates a script that will get num of result items from the iterator right in
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// the VM and return them to you. It's only limited by VM stack and GAS available
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// for RPC invocations.
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func (t *BaseReader) TokensOfExpanded(account util.Uint160, num int) ([][]byte, error) {
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return unwrap.ArrayOfBytes(t.invoker.CallAndExpandIterator(t.hash, "tokensOf", num, account))
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}
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// Transfer creates and sends a transaction that performs a `transfer` method
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// call using the given parameters and checks for this call result, failing the
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// transaction if it's not true. It works for divisible NFTs only when there is
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// one owner for the particular token. The returned values are transaction hash,
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// its ValidUntilBlock value and an error if any.
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func (t *Base) Transfer(to util.Uint160, id []byte, data interface{}) (util.Uint256, uint32, error) {
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script, err := t.transferScript(to, id, data)
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if err != nil {
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return util.Uint256{}, 0, err
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}
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return t.actor.SendRun(script)
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}
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// TransferTransaction creates a transaction that performs a `transfer` method
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// call using the given parameters and checks for this call result, failing the
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// transaction if it's not true. It works for divisible NFTs only when there is
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// one owner for the particular token. This transaction is signed, but not sent
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// to the network, instead it's returned to the caller.
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func (t *Base) TransferTransaction(to util.Uint160, id []byte, data interface{}) (*transaction.Transaction, error) {
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script, err := t.transferScript(to, id, data)
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if err != nil {
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return nil, err
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}
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return t.actor.MakeRun(script)
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}
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// TransferUnsigned creates a transaction that performs a `transfer` method
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// call using the given parameters and checks for this call result, failing the
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// transaction if it's not true. It works for divisible NFTs only when there is
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// one owner for the particular token. This transaction is not signed and just
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// returned to the caller.
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func (t *Base) TransferUnsigned(to util.Uint160, id []byte, data interface{}) (*transaction.Transaction, error) {
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script, err := t.transferScript(to, id, data)
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if err != nil {
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return nil, err
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}
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return t.actor.MakeUnsignedRun(script, nil)
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}
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func (t *Base) transferScript(params ...interface{}) ([]byte, error) {
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return smartcontract.CreateCallWithAssertScript(t.hash, "transfer", params...)
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}
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// Next returns the next set of elements from the iterator (up to num of them).
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// It can return less than num elements in case iterator doesn't have that many
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// or zero elements if the iterator has no more elements or the session is
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// expired.
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func (v *TokenIterator) Next(num int) ([][]byte, error) {
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items, err := v.client.TraverseIterator(v.session, &v.iterator, num)
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if err != nil {
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return nil, err
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}
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res := make([][]byte, len(items))
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for i := range items {
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b, err := items[i].TryBytes()
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if err != nil {
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return nil, fmt.Errorf("element %d is not a byte string: %w", i, err)
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}
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res[i] = b
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}
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return res, nil
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}
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// Terminate closes the iterator session used by TokenIterator (if it's
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// session-based).
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func (v *TokenIterator) Terminate() error {
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if v.iterator.ID == nil {
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return nil
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}
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return v.client.TerminateSession(v.session)
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}
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// UnwrapKnownProperties can be used as a proxy function to extract well-known
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// NEP-11 properties (name/description/image/tokenURI) defined in the standard.
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// These properties are checked to be valid UTF-8 strings, but can contain
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// control codes or special characters.
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func UnwrapKnownProperties(m *stackitem.Map, err error) (map[string]string, error) {
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if err != nil {
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return nil, err
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}
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elems := m.Value().([]stackitem.MapElement)
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res := make(map[string]string)
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for _, e := range elems {
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k, err := e.Key.TryBytes()
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if err != nil { // Shouldn't ever happen in the valid Map, but.
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continue
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}
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ks := string(k)
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if !result.KnownNEP11Properties[ks] { // Some additional elements are OK.
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continue
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}
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v, err := e.Value.TryBytes()
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if err != nil { // But known ones MUST be proper strings.
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return nil, fmt.Errorf("invalid %s property: %w", ks, err)
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}
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if !utf8.Valid(v) {
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return nil, fmt.Errorf("invalid %s property: not a UTF-8 string", ks)
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}
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res[ks] = string(v)
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}
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return res, nil
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}
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