rpcclient: provide nep11 package for NEP-11 tokens

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).

cli/wallet/nep11.go

@@ -5,16 +5,20 @@ import (
 	"errors"
 	"fmt"
 	"math/big"
+	"strconv"
 
 	"github.com/nspcc-dev/neo-go/cli/cmdargs"
 	"github.com/nspcc-dev/neo-go/cli/flags"
 	"github.com/nspcc-dev/neo-go/cli/input"
 	"github.com/nspcc-dev/neo-go/cli/options"
 	"github.com/nspcc-dev/neo-go/cli/paramcontext"
+	"github.com/nspcc-dev/neo-go/pkg/config"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
 	"github.com/nspcc-dev/neo-go/pkg/encoding/address"
 	"github.com/nspcc-dev/neo-go/pkg/encoding/fixedn"
 	"github.com/nspcc-dev/neo-go/pkg/rpcclient"
+	"github.com/nspcc-dev/neo-go/pkg/rpcclient/invoker"
+	"github.com/nspcc-dev/neo-go/pkg/rpcclient/nep11"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
@@ -23,6 +27,7 @@ import (
 )
 
 func newNEP11Commands() []cli.Command {
+	maxIters := strconv.Itoa(config.DefaultMaxIteratorResultItems)
 	tokenAddressFlag := flags.AddressFlag{
 		Name:  "token",
 		Usage: "Token contract address or hash in LE",
@@ -119,7 +124,7 @@ func newNEP11Commands() []cli.Command {
 		},
 		{
 			Name:      "ownerOfD",
-			Usage:     "print set of owners of divisible NEP-11 token with the specified ID (the default MaxIteratorResultItems will be printed at max)",
+			Usage:     "print set of owners of divisible NEP-11 token with the specified ID (" + maxIters + " will be printed at max)",
 			UsageText: "ownerOfD --rpc-endpoint <node> --timeout <time> --token <hash> --id <token-id>",
 			Action:    printNEP11DOwner,
 			Flags: append([]cli.Flag{
@@ -129,7 +134,7 @@ func newNEP11Commands() []cli.Command {
 		},
 		{
 			Name:      "tokensOf",
-			Usage:     "print list of tokens IDs for the specified NFT owner (the default MaxIteratorResultItems will be printed at max)",
+			Usage:     "print list of tokens IDs for the specified NFT owner (" + maxIters + " will be printed at max)",
 			UsageText: "tokensOf --rpc-endpoint <node> --timeout <time> --token <hash> --address <addr>",
 			Action:    printNEP11TokensOf,
 			Flags: append([]cli.Flag{
@@ -139,7 +144,7 @@ func newNEP11Commands() []cli.Command {
 		},
 		{
 			Name:      "tokens",
-			Usage:     "print list of tokens IDs minted by the specified NFT (optional method; the default MaxIteratorResultItems will be printed at max)",
+			Usage:     "print list of tokens IDs minted by the specified NFT (optional method; " + maxIters + " will be printed at max)",
 			UsageText: "tokens --rpc-endpoint <node> --timeout <time> --token <hash>",
 			Action:    printNEP11Tokens,
 			Flags: append([]cli.Flag{
@@ -211,6 +216,8 @@ func getNEP11Balance(ctx *cli.Context) error {
 			return cli.NewExitError(err.Error(), 1)
 		}
 	}
+	// Always initialize divisible token to be able to use both balanceOf methods.
+	n11 := nep11.NewDivisibleReader(invoker.New(c, nil), token.Hash)
 
 	tokenID := ctx.String("id")
 	tokenIDBytes, err := hex.DecodeString(tokenID)
@@ -228,16 +235,16 @@ func getNEP11Balance(ctx *cli.Context) error {
 		}
 		fmt.Fprintf(ctx.App.Writer, "Account %s\n", acc.Address)
 
-		var amount int64
+		var amount *big.Int
 		if len(tokenIDBytes) == 0 {
-			amount, err = c.NEP11BalanceOf(token.Hash, addrHash)
+			amount, err = n11.BalanceOf(addrHash)
 		} else {
-			amount, err = c.NEP11DBalanceOf(token.Hash, addrHash, tokenIDBytes)
+			amount, err = n11.BalanceOfD(addrHash, tokenIDBytes)
 		}
 		if err != nil {
 			continue
 		}
-		amountStr := fixedn.ToString(big.NewInt(amount), int(token.Decimals))
+		amountStr := fixedn.ToString(amount, int(token.Decimals))
 
 		format := "%s: %s (%s)\n"
 		formatArgs := []interface{}{token.Symbol, token.Name, token.Hash.StringLE()}
@@ -270,9 +277,9 @@ func signAndSendNEP11Transfer(ctx *cli.Context, c *rpcclient.Client, acc *wallet
 		if err != nil {
 			return cli.NewExitError(fmt.Errorf("bad account address: %w", err), 1)
 		}
-		tx, err = c.CreateNEP11TransferTx(acc, token, int64(gas), cosigners, from, to, amount, tokenID, data)
+		tx, err = c.CreateNEP11TransferTx(acc, token, int64(gas), cosigners, from, to, amount, tokenID, data) //nolint:staticcheck // SA1019: c.CreateNEP11TransferTx is deprecated
 	} else {
-		tx, err = c.CreateNEP11TransferTx(acc, token, int64(gas), cosigners, to, tokenID, data)
+		tx, err = c.CreateNEP11TransferTx(acc, token, int64(gas), cosigners, to, tokenID, data) //nolint:staticcheck // SA1019: c.CreateNEP11TransferTx is deprecated
 	}
 	if err != nil {
 		return cli.NewExitError(err, 1)
@@ -346,7 +353,8 @@ func printNEP11Owner(ctx *cli.Context, divisible bool) error {
 	}
 
 	if divisible {
-		result, err := c.NEP11DUnpackedOwnerOf(tokenHash.Uint160(), tokenIDBytes)
+		n11 := nep11.NewDivisibleReader(invoker.New(c, nil), tokenHash.Uint160())
+		result, err := n11.OwnerOfExpanded(tokenIDBytes, config.DefaultMaxIteratorResultItems)
 		if err != nil {
 			return cli.NewExitError(fmt.Sprintf("failed to call NEP-11 divisible `ownerOf` method: %s", err.Error()), 1)
 		}
@@ -354,7 +362,8 @@ func printNEP11Owner(ctx *cli.Context, divisible bool) error {
 			fmt.Fprintln(ctx.App.Writer, address.Uint160ToString(h))
 		}
 	} else {
-		result, err := c.NEP11NDOwnerOf(tokenHash.Uint160(), tokenIDBytes)
+		n11 := nep11.NewNonDivisibleReader(invoker.New(c, nil), tokenHash.Uint160())
+		result, err := n11.OwnerOf(tokenIDBytes)
 		if err != nil {
 			return cli.NewExitError(fmt.Sprintf("failed to call NEP-11 non-divisible `ownerOf` method: %s", err.Error()), 1)
 		}
@@ -384,7 +393,8 @@ func printNEP11TokensOf(ctx *cli.Context) error {
 		return cli.NewExitError(err, 1)
 	}
 
-	result, err := c.NEP11UnpackedTokensOf(tokenHash.Uint160(), acc.Uint160())
+	n11 := nep11.NewBaseReader(invoker.New(c, nil), tokenHash.Uint160())
+	result, err := n11.TokensOfExpanded(acc.Uint160(), config.DefaultMaxIteratorResultItems)
 	if err != nil {
 		return cli.NewExitError(fmt.Sprintf("failed to call NEP-11 `tokensOf` method: %s", err.Error()), 1)
 	}
@@ -413,7 +423,8 @@ func printNEP11Tokens(ctx *cli.Context) error {
 		return cli.NewExitError(err, 1)
 	}
 
-	result, err := c.NEP11UnpackedTokens(tokenHash.Uint160())
+	n11 := nep11.NewBaseReader(invoker.New(c, nil), tokenHash.Uint160())
+	result, err := n11.TokensExpanded(config.DefaultMaxIteratorResultItems)
 	if err != nil {
 		return cli.NewExitError(fmt.Sprintf("failed to call optional NEP-11 `tokens` method: %s", err.Error()), 1)
 	}
@@ -451,7 +462,8 @@ func printNEP11Properties(ctx *cli.Context) error {
 		return cli.NewExitError(err, 1)
 	}
 
-	result, err := c.NEP11Properties(tokenHash.Uint160(), tokenIDBytes)
+	n11 := nep11.NewBaseReader(invoker.New(c, nil), tokenHash.Uint160())
+	result, err := n11.Properties(tokenIDBytes)
 	if err != nil {
 		return cli.NewExitError(fmt.Sprintf("failed to call NEP-11 `properties` method: %s", err.Error()), 1)
 	}

pkg/rpcclient/nep11.go

@@ -17,21 +17,33 @@ import (
 )
 
 // NEP11Decimals invokes `decimals` NEP-11 method on the specified contract.
+//
+// Deprecated: please use nep11 package, this method will be removed in future
+// versions.
 func (c *Client) NEP11Decimals(tokenHash util.Uint160) (int64, error) {
 	return c.nepDecimals(tokenHash)
 }
 
 // NEP11Symbol invokes `symbol` NEP-11 method on the specified contract.
+//
+// Deprecated: please use nep11 package, this method will be removed in future
+// versions.
 func (c *Client) NEP11Symbol(tokenHash util.Uint160) (string, error) {
 	return c.nepSymbol(tokenHash)
 }
 
 // NEP11TotalSupply invokes `totalSupply` NEP-11 method on the specified contract.
+//
+// Deprecated: please use nep11 package, this method will be removed in future
+// versions.
 func (c *Client) NEP11TotalSupply(tokenHash util.Uint160) (int64, error) {
 	return c.nepTotalSupply(tokenHash)
 }
 
 // NEP11BalanceOf invokes `balanceOf` NEP-11 method on the specified contract.
+//
+// Deprecated: please use nep11 package, this method will be removed in future
+// versions.
 func (c *Client) NEP11BalanceOf(tokenHash, owner util.Uint160) (int64, error) {
 	return c.nepBalanceOf(tokenHash, owner, nil)
 }
@@ -44,6 +56,9 @@ func (c *Client) NEP11TokenInfo(tokenHash util.Uint160) (*wallet.Token, error) {
 // TransferNEP11 creates an invocation transaction that invokes 'transfer' method
 // on the given token to move the whole NEP-11 token with the specified token ID to
 // the given account and sends it to the network returning just a hash of it.
+//
+// Deprecated: please use nep11 package, this method will be removed in future
+// versions.
 func (c *Client) TransferNEP11(acc *wallet.Account, to util.Uint160,
 	tokenHash util.Uint160, tokenID string, data interface{}, gas int64, cosigners []SignerAccount) (util.Uint256, error) {
 	tx, err := c.CreateNEP11TransferTx(acc, tokenHash, gas, cosigners, to, tokenID, data)
@@ -61,6 +76,9 @@ func (c *Client) TransferNEP11(acc *wallet.Account, to util.Uint160,
 // helper for TransferNEP11 and TransferNEP11D.
 // `args` for TransferNEP11:  to util.Uint160, tokenID string, data interface{};
 // `args` for TransferNEP11D: from, to util.Uint160, amount int64, tokenID string, data interface{}.
+//
+// Deprecated: please use nep11 package, this method will be removed in future
+// versions.
 func (c *Client) CreateNEP11TransferTx(acc *wallet.Account, tokenHash util.Uint160,
 	gas int64, cosigners []SignerAccount, args ...interface{}) (*transaction.Transaction, error) {
 	script, err := smartcontract.CreateCallWithAssertScript(tokenHash, "transfer", args...)
@@ -85,6 +103,9 @@ func (c *Client) CreateNEP11TransferTx(acc *wallet.Account, tokenHash util.Uint1
 // Iterator itself, the third one is an error. Use TraverseIterator method to
 // traverse iterator values or TerminateSession to terminate opened iterator
 // session. See TraverseIterator and TerminateSession documentation for more details.
+//
+// Deprecated: please use nep11 package, this method will be removed in future
+// versions.
 func (c *Client) NEP11TokensOf(tokenHash util.Uint160, owner util.Uint160) (uuid.UUID, result.Iterator, error) {
 	return unwrap.SessionIterator(c.reader.Call(tokenHash, "tokensOf", owner))
 }
@@ -93,6 +114,9 @@ func (c *Client) NEP11TokensOf(tokenHash util.Uint160, owner util.Uint160) (uuid
 // (config.DefaultMaxIteratorResultItems at max). It differs from NEP11TokensOf in that no iterator session
 // is used to retrieve values from iterator. Instead, unpacking VM script is created and invoked via
 // `invokescript` JSON-RPC call.
+//
+// Deprecated: please use nep11 package, this method will be removed in future
+// versions.
 func (c *Client) NEP11UnpackedTokensOf(tokenHash util.Uint160, owner util.Uint160) ([][]byte, error) {
 	return unwrap.ArrayOfBytes(c.reader.CallAndExpandIterator(tokenHash, "tokensOf", config.DefaultMaxIteratorResultItems, owner))
 }
@@ -101,6 +125,9 @@ func (c *Client) NEP11UnpackedTokensOf(tokenHash util.Uint160, owner util.Uint16
 
 // NEP11NDOwnerOf invokes `ownerOf` non-divisible NEP-11 method with the
 // specified token ID on the specified contract.
+//
+// Deprecated: please use nep11 package, this method will be removed in future
+// versions.
 func (c *Client) NEP11NDOwnerOf(tokenHash util.Uint160, tokenID []byte) (util.Uint160, error) {
 	return unwrap.Uint160(c.reader.Call(tokenHash, "ownerOf", tokenID))
 }
@@ -113,6 +140,9 @@ func (c *Client) NEP11NDOwnerOf(tokenHash util.Uint160, tokenID []byte) (util.Ui
 // method on the given token to move the specified amount of divisible NEP-11 assets
 // (in FixedN format using contract's number of decimals) to the given account and
 // sends it to the network returning just a hash of it.
+//
+// Deprecated: please use nep11 package, this method will be removed in future
+// versions.
 func (c *Client) TransferNEP11D(acc *wallet.Account, to util.Uint160,
 	tokenHash util.Uint160, amount int64, tokenID []byte, data interface{}, gas int64, cosigners []SignerAccount) (util.Uint256, error) {
 	from, err := address.StringToUint160(acc.Address)
@@ -129,6 +159,9 @@ func (c *Client) TransferNEP11D(acc *wallet.Account, to util.Uint160,
 
 // NEP11DBalanceOf invokes `balanceOf` divisible NEP-11 method on a
 // specified contract.
+//
+// Deprecated: please use nep11 package, this method will be removed in future
+// versions.
 func (c *Client) NEP11DBalanceOf(tokenHash, owner util.Uint160, tokenID []byte) (int64, error) {
 	return c.nepBalanceOf(tokenHash, owner, tokenID)
 }
@@ -137,6 +170,9 @@ func (c *Client) NEP11DBalanceOf(tokenHash, owner util.Uint160, tokenID []byte)
 // is the session ID, the second one is Iterator itself, the third one is an error. Use TraverseIterator
 // method to traverse iterator values or TerminateSession to terminate opened iterator session. See
 // TraverseIterator and TerminateSession documentation for more details.
+//
+// Deprecated: please use nep11 package, this method will be removed in future
+// versions.
 func (c *Client) NEP11DOwnerOf(tokenHash util.Uint160, tokenID []byte) (uuid.UUID, result.Iterator, error) {
 	return unwrap.SessionIterator(c.reader.Call(tokenHash, "ownerOf", tokenID))
 }
@@ -145,6 +181,9 @@ func (c *Client) NEP11DOwnerOf(tokenHash util.Uint160, tokenID []byte) (uuid.UUI
 // (config.DefaultMaxIteratorResultItems at max). It differs from NEP11DOwnerOf in that no
 // iterator session is used to retrieve values from iterator. Instead, unpacking VM
 // script is created and invoked via `invokescript` JSON-RPC call.
+//
+// Deprecated: please use nep11 package, this method will be removed in future
+// versions.
 func (c *Client) NEP11DUnpackedOwnerOf(tokenHash util.Uint160, tokenID []byte) ([]util.Uint160, error) {
 	arr, err := unwrap.ArrayOfBytes(c.reader.CallAndExpandIterator(tokenHash, "ownerOf", config.DefaultMaxIteratorResultItems, tokenID))
 	if err != nil {
@@ -166,6 +205,9 @@ func (c *Client) NEP11DUnpackedOwnerOf(tokenHash util.Uint160, tokenID []byte) (
 
 // NEP11Properties invokes `properties` optional NEP-11 method on the
 // specified contract.
+//
+// Deprecated: please use nep11 package, this method will be removed in future
+// versions.
 func (c *Client) NEP11Properties(tokenHash util.Uint160, tokenID []byte) (*stackitem.Map, error) {
 	return unwrap.Map(c.reader.Call(tokenHash, "properties", tokenID))
 }
@@ -175,6 +217,9 @@ func (c *Client) NEP11Properties(tokenHash util.Uint160, tokenID []byte) (*stack
 // error. Use TraverseIterator method to traverse iterator values or
 // TerminateSession to terminate opened iterator session. See TraverseIterator and
 // TerminateSession documentation for more details.
+//
+// Deprecated: please use nep11 package, this method will be removed in future
+// versions.
 func (c *Client) NEP11Tokens(tokenHash util.Uint160) (uuid.UUID, result.Iterator, error) {
 	return unwrap.SessionIterator(c.reader.Call(tokenHash, "tokens"))
 }
@@ -183,6 +228,9 @@ func (c *Client) NEP11Tokens(tokenHash util.Uint160) (uuid.UUID, result.Iterator
 // (config.DefaultMaxIteratorResultItems at max). It differs from NEP11Tokens in that no
 // iterator session is used to retrieve values from iterator. Instead, unpacking
 // VM script is created and invoked via `invokescript` JSON-RPC call.
+//
+// Deprecated: please use nep11 package, this method will be removed in future
+// versions.
 func (c *Client) NEP11UnpackedTokens(tokenHash util.Uint160) ([][]byte, error) {
 	return unwrap.ArrayOfBytes(c.reader.CallAndExpandIterator(tokenHash, "tokens", config.DefaultMaxIteratorResultItems))
 }

pkg/rpcclient/nep11/base.go

@@ -0,0 +1,247 @@
+/*
+Package nep11 contains RPC wrappers for NEP-11 contracts.
+
+The set of types provided is split between common NEP-11 methods (BaseReader and
+Base types) and divisible (DivisibleReader and Divisible) and non-divisible
+(NonDivisibleReader and NonDivisible). If you don't know the type of NEP-11
+contract you're going to use you can use Base and BaseReader types for many
+purposes, otherwise more specific types are recommended.
+*/
+package nep11
+
+import (
+	"fmt"
+	"math/big"
+	"unicode/utf8"
+
+	"github.com/google/uuid"
+	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
+	"github.com/nspcc-dev/neo-go/pkg/neorpc/result"
+	"github.com/nspcc-dev/neo-go/pkg/rpcclient/neptoken"
+	"github.com/nspcc-dev/neo-go/pkg/rpcclient/unwrap"
+	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
+)
+
+// Invoker is used by reader types to call various methods.
+type Invoker interface {
+	neptoken.Invoker
+
+	CallAndExpandIterator(contract util.Uint160, method string, maxItems int, params ...interface{}) (*result.Invoke, error)
+	TerminateSession(sessionID uuid.UUID) error
+	TraverseIterator(sessionID uuid.UUID, iterator *result.Iterator, num int) ([]stackitem.Item, error)
+}
+
+// Actor is used by complete NEP-11 types to create and send transactions.
+type Actor interface {
+	Invoker
+
+	MakeRun(script []byte) (*transaction.Transaction, error)
+	MakeUnsignedRun(script []byte, attrs []transaction.Attribute) (*transaction.Transaction, error)
+	SendRun(script []byte) (util.Uint256, uint32, error)
+}
+
+// BaseReader is a reader interface for common divisible and non-divisible NEP-11
+// methods. It allows to invoke safe methods.
+type BaseReader struct {
+	neptoken.Base
+
+	invoker Invoker
+	hash    util.Uint160
+}
+
+// Base is a state-changing interface for common divisible and non-divisible NEP-11
+// methods.
+type Base struct {
+	BaseReader
+
+	actor Actor
+}
+
+// TransferEvent represents a Transfer event as defined in the NEP-11 standard.
+type TransferEvent struct {
+	From   util.Uint160
+	To     util.Uint160
+	Amount *big.Int
+	ID     []byte
+}
+
+// TokenIterator is used for iterating over TokensOf results.
+type TokenIterator struct {
+	client   Invoker
+	session  uuid.UUID
+	iterator result.Iterator
+}
+
+// NewBaseReader creates an instance of BaseReader for a contract with the given
+// hash using the given invoker.
+func NewBaseReader(invoker Invoker, hash util.Uint160) *BaseReader {
+	return &BaseReader{*neptoken.New(invoker, hash), invoker, hash}
+}
+
+// NewBase creates an instance of Base for contract with the given
+// hash using the given actor.
+func NewBase(actor Actor, hash util.Uint160) *Base {
+	return &Base{*NewBaseReader(actor, hash), actor}
+}
+
+// BalanceOf returns the number of NFTs owned by the given account. For divisible
+// NFTs that's the sum of all parts of tokens.
+func (t *BaseReader) BalanceOf(account util.Uint160) (*big.Int, error) {
+	return unwrap.BigInt(t.invoker.Call(t.hash, "balanceOf", account))
+}
+
+// Properties returns a set of token's properties such as name or URL. The map
+// is returned as is from this method (stack item) for maximum flexibility,
+// contracts can return a lot of specific data there. Most of the time though
+// they return well-defined properties outlined in NEP-11 and
+// UnwrapKnownProperties can be used to get them in more convenient way. It's an
+// optional method per NEP-11 specification, so it can fail.
+func (t *BaseReader) Properties(token []byte) (*stackitem.Map, error) {
+	return unwrap.Map(t.invoker.Call(t.hash, "properties", token))
+}
+
+// Tokens returns an iterator that allows to retrieve all tokens minted by the
+// contract. It depends on the server to provide proper session-based
+// iterator, but can also work with expanded one. The method itself is optional
+// per NEP-11 specification, so it can fail.
+func (t *BaseReader) Tokens() (*TokenIterator, error) {
+	sess, iter, err := unwrap.SessionIterator(t.invoker.Call(t.hash, "tokens"))
+	if err != nil {
+		return nil, err
+	}
+	return &TokenIterator{t.invoker, sess, iter}, nil
+}
+
+// TokensExpanded uses the same NEP-11 method as Tokens, but can be useful if
+// the server used doesn't support sessions and doesn't expand iterators. It
+// creates a script that will get num of result items from the iterator right in
+// the VM and return them to you. It's only limited by VM stack and GAS available
+// for RPC invocations.
+func (t *BaseReader) TokensExpanded(num int) ([][]byte, error) {
+	return unwrap.ArrayOfBytes(t.invoker.CallAndExpandIterator(t.hash, "tokens", num))
+}
+
+// TokensOf returns an iterator that allows to walk through all tokens owned by
+// the given account. It depends on the server to provide proper session-based
+// iterator, but can also work with expanded one.
+func (t *BaseReader) TokensOf(account util.Uint160) (*TokenIterator, error) {
+	sess, iter, err := unwrap.SessionIterator(t.invoker.Call(t.hash, "tokensOf", account))
+	if err != nil {
+		return nil, err
+	}
+	return &TokenIterator{t.invoker, sess, iter}, nil
+}
+
+// TokensOfExpanded uses the same NEP-11 method as TokensOf, but can be useful if
+// the server used doesn't support sessions and doesn't expand iterators. It
+// creates a script that will get num of result items from the iterator right in
+// the VM and return them to you. It's only limited by VM stack and GAS available
+// for RPC invocations.
+func (t *BaseReader) TokensOfExpanded(account util.Uint160, num int) ([][]byte, error) {
+	return unwrap.ArrayOfBytes(t.invoker.CallAndExpandIterator(t.hash, "tokensOf", num, account))
+}
+
+// Transfer creates and sends a transaction that performs a `transfer` method
+// call using the given parameters and checks for this call result, failing the
+// transaction if it's not true. It works for divisible NFTs only when there is
+// one owner for the particular token. The returned values are transaction hash,
+// its ValidUntilBlock value and an error if any.
+func (t *Base) Transfer(to util.Uint160, id []byte, data interface{}) (util.Uint256, uint32, error) {
+	script, err := t.transferScript(to, id, data)
+	if err != nil {
+		return util.Uint256{}, 0, err
+	}
+	return t.actor.SendRun(script)
+}
+
+// TransferTransaction creates a transaction that performs a `transfer` method
+// call using the given parameters and checks for this call result, failing the
+// transaction if it's not true. It works for divisible NFTs only when there is
+// one owner for the particular token. This transaction is signed, but not sent
+// to the network, instead it's returned to the caller.
+func (t *Base) TransferTransaction(to util.Uint160, id []byte, data interface{}) (*transaction.Transaction, error) {
+	script, err := t.transferScript(to, id, data)
+	if err != nil {
+		return nil, err
+	}
+	return t.actor.MakeRun(script)
+}
+
+// TransferUnsigned creates a transaction that performs a `transfer` method
+// call using the given parameters and checks for this call result, failing the
+// transaction if it's not true. It works for divisible NFTs only when there is
+// one owner for the particular token. This transaction is not signed and just
+// returned to the caller.
+func (t *Base) TransferUnsigned(to util.Uint160, id []byte, data interface{}) (*transaction.Transaction, error) {
+	script, err := t.transferScript(to, id, data)
+	if err != nil {
+		return nil, err
+	}
+	return t.actor.MakeUnsignedRun(script, nil)
+}
+
+func (t *Base) transferScript(params ...interface{}) ([]byte, error) {
+	return smartcontract.CreateCallWithAssertScript(t.hash, "transfer", params...)
+}
+
+// Next returns the next set of elements from the iterator (up to num of them).
+// It can return less than num elements in case iterator doesn't have that many
+// or zero elements if the iterator has no more elements or the session is
+// expired.
+func (v *TokenIterator) Next(num int) ([][]byte, error) {
+	items, err := v.client.TraverseIterator(v.session, &v.iterator, num)
+	if err != nil {
+		return nil, err
+	}
+	res := make([][]byte, len(items))
+	for i := range items {
+		b, err := items[i].TryBytes()
+		if err != nil {
+			return nil, fmt.Errorf("element %d is not a byte string: %w", i, err)
+		}
+		res[i] = b
+	}
+	return res, nil
+}
+
+// Terminate closes the iterator session used by TokenIterator (if it's
+// session-based).
+func (v *TokenIterator) Terminate() error {
+	if v.iterator.ID == nil {
+		return nil
+	}
+	return v.client.TerminateSession(v.session)
+}
+
+// UnwrapKnownProperties can be used as a proxy function to extract well-known
+// NEP-11 properties (name/description/image/tokenURI) defined in the standard.
+// These properties are checked to be valid UTF-8 strings, but can contain
+// control codes or special characters.
+func UnwrapKnownProperties(m *stackitem.Map, err error) (map[string]string, error) {
+	if err != nil {
+		return nil, err
+	}
+	elems := m.Value().([]stackitem.MapElement)
+	res := make(map[string]string)
+	for _, e := range elems {
+		k, err := e.Key.TryBytes()
+		if err != nil { // Shouldn't ever happen in the valid Map, but.
+			continue
+		}
+		ks := string(k)
+		if !result.KnownNEP11Properties[ks] { // Some additional elements are OK.
+			continue
+		}
+		v, err := e.Value.TryBytes()
+		if err != nil { // But known ones MUST be proper strings.
+			return nil, fmt.Errorf("invalid %s property: %w", ks, err)
+		}
+		if !utf8.Valid(v) {
+			return nil, fmt.Errorf("invalid %s property: not a UTF-8 string", ks)
+		}
+		res[ks] = string(v)
+	}
+	return res, nil
+}

pkg/rpcclient/nep11/base_test.go

@@ -0,0 +1,305 @@
+package nep11
+
+import (
+	"errors"
+	"math/big"
+	"testing"
+
+	"github.com/google/uuid"
+	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
+	"github.com/nspcc-dev/neo-go/pkg/neorpc/result"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
+	"github.com/stretchr/testify/require"
+)
+
+type testAct struct {
+	err error
+	res *result.Invoke
+	tx  *transaction.Transaction
+	txh util.Uint256
+	vub uint32
+}
+
+func (t *testAct) Call(contract util.Uint160, operation string, params ...interface{}) (*result.Invoke, error) {
+	return t.res, t.err
+}
+func (t *testAct) MakeRun(script []byte) (*transaction.Transaction, error) {
+	return t.tx, t.err
+}
+func (t *testAct) MakeUnsignedRun(script []byte, attrs []transaction.Attribute) (*transaction.Transaction, error) {
+	return t.tx, t.err
+}
+func (t *testAct) SendRun(script []byte) (util.Uint256, uint32, error) {
+	return t.txh, t.vub, t.err
+}
+func (t *testAct) CallAndExpandIterator(contract util.Uint160, method string, maxItems int, params ...interface{}) (*result.Invoke, error) {
+	return t.res, t.err
+}
+func (t *testAct) TerminateSession(sessionID uuid.UUID) error {
+	return t.err
+}
+func (t *testAct) TraverseIterator(sessionID uuid.UUID, iterator *result.Iterator, num int) ([]stackitem.Item, error) {
+	return t.res.Stack, t.err
+}
+
+func TestReaderBalanceOf(t *testing.T) {
+	ta := new(testAct)
+	tr := NewBaseReader(ta, util.Uint160{1, 2, 3})
+
+	ta.err = errors.New("")
+	_, err := tr.BalanceOf(util.Uint160{3, 2, 1})
+	require.Error(t, err)
+
+	ta.err = nil
+	ta.res = &result.Invoke{
+		State: "HALT",
+		Stack: []stackitem.Item{
+			stackitem.Make(100500),
+		},
+	}
+	bal, err := tr.BalanceOf(util.Uint160{3, 2, 1})
+	require.NoError(t, err)
+	require.Equal(t, big.NewInt(100500), bal)
+
+	ta.res = &result.Invoke{
+		State: "HALT",
+		Stack: []stackitem.Item{
+			stackitem.Make([]stackitem.Item{}),
+		},
+	}
+	_, err = tr.BalanceOf(util.Uint160{3, 2, 1})
+	require.Error(t, err)
+}
+
+func TestReaderProperties(t *testing.T) {
+	ta := new(testAct)
+	tr := NewBaseReader(ta, util.Uint160{1, 2, 3})
+
+	ta.err = errors.New("")
+	_, err := tr.Properties([]byte{3, 2, 1})
+	require.Error(t, err)
+
+	ta.res = &result.Invoke{
+		State: "HALT",
+		Stack: []stackitem.Item{
+			stackitem.Make([]stackitem.Item{}),
+		},
+	}
+	_, err = tr.Properties([]byte{3, 2, 1})
+	require.Error(t, err)
+
+	ta.err = nil
+	ta.res = &result.Invoke{
+		State: "HALT",
+		Stack: []stackitem.Item{
+			stackitem.NewMap(),
+		},
+	}
+	m, err := tr.Properties([]byte{3, 2, 1})
+	require.NoError(t, err)
+	require.Equal(t, 0, m.Len())
+}
+
+func TestReaderTokensOfExpanded(t *testing.T) {
+	ta := new(testAct)
+	tr := NewBaseReader(ta, util.Uint160{1, 2, 3})
+
+	for name, fun := range map[string]func(int) ([][]byte, error){
+		"Tokens": tr.TokensExpanded,
+		"TokensOf": func(n int) ([][]byte, error) {
+			return tr.TokensOfExpanded(util.Uint160{1, 2, 3}, n)
+		},
+	} {
+		t.Run(name, func(t *testing.T) {
+			ta.err = errors.New("")
+			_, err := fun(1)
+			require.Error(t, err)
+
+			ta.err = nil
+			ta.res = &result.Invoke{
+				State: "HALT",
+				Stack: []stackitem.Item{
+					stackitem.Make(100500),
+				},
+			}
+			_, err = fun(1)
+			require.Error(t, err)
+
+			ta.res = &result.Invoke{
+				State: "HALT",
+				Stack: []stackitem.Item{
+					stackitem.Make([]stackitem.Item{stackitem.Make("one")}),
+				},
+			}
+			toks, err := fun(1)
+			require.NoError(t, err)
+			require.Equal(t, [][]byte{[]byte("one")}, toks)
+		})
+	}
+}
+
+func TestReaderTokensOf(t *testing.T) {
+	ta := new(testAct)
+	tr := NewBaseReader(ta, util.Uint160{1, 2, 3})
+
+	for name, fun := range map[string]func() (*TokenIterator, error){
+		"Tokens": tr.Tokens,
+		"TokensOf": func() (*TokenIterator, error) {
+			return tr.TokensOf(util.Uint160{1, 2, 3})
+		},
+	} {
+		t.Run(name, func(t *testing.T) {
+			ta.err = errors.New("")
+			_, err := fun()
+			require.Error(t, err)
+
+			iid := uuid.New()
+			ta.err = nil
+			ta.res = &result.Invoke{
+				Session: uuid.New(),
+				State:   "HALT",
+				Stack: []stackitem.Item{
+					stackitem.NewInterop(result.Iterator{
+						ID: &iid,
+					}),
+				},
+			}
+			iter, err := fun()
+			require.NoError(t, err)
+
+			ta.res = &result.Invoke{
+				Stack: []stackitem.Item{
+					stackitem.Make("one"),
+					stackitem.Make([]stackitem.Item{}),
+				},
+			}
+			_, err = iter.Next(10)
+			require.Error(t, err)
+
+			ta.res = &result.Invoke{
+				Stack: []stackitem.Item{
+					stackitem.Make("one"),
+					stackitem.Make("two"),
+				},
+			}
+			vals, err := iter.Next(10)
+			require.NoError(t, err)
+			require.Equal(t, [][]byte{[]byte("one"), []byte("two")}, vals)
+
+			ta.err = errors.New("")
+			_, err = iter.Next(1)
+			require.Error(t, err)
+
+			err = iter.Terminate()
+			require.Error(t, err)
+
+			// Value-based iterator.
+			ta.err = nil
+			ta.res = &result.Invoke{
+				State: "HALT",
+				Stack: []stackitem.Item{
+					stackitem.NewInterop(result.Iterator{
+						Values: []stackitem.Item{
+							stackitem.Make("one"),
+							stackitem.Make("two"),
+						},
+					}),
+				},
+			}
+			iter, err = fun()
+			require.NoError(t, err)
+
+			ta.err = errors.New("")
+			err = iter.Terminate()
+			require.NoError(t, err)
+		})
+	}
+}
+
+func TestTokenTransfer(t *testing.T) {
+	ta := new(testAct)
+	tok := NewBase(ta, util.Uint160{1, 2, 3})
+
+	ta.err = errors.New("")
+	_, _, err := tok.Transfer(util.Uint160{3, 2, 1}, []byte{3, 2, 1}, nil)
+	require.Error(t, err)
+
+	ta.err = nil
+	ta.txh = util.Uint256{1, 2, 3}
+	ta.vub = 42
+	h, vub, err := tok.Transfer(util.Uint160{3, 2, 1}, []byte{3, 2, 1}, nil)
+	require.NoError(t, err)
+	require.Equal(t, ta.txh, h)
+	require.Equal(t, ta.vub, vub)
+
+	_, _, err = tok.Transfer(util.Uint160{3, 2, 1}, []byte{3, 2, 1}, stackitem.NewMap())
+	require.Error(t, err)
+}
+
+func TestTokenTransferTransaction(t *testing.T) {
+	ta := new(testAct)
+	tok := NewBase(ta, util.Uint160{1, 2, 3})
+
+	for _, fun := range []func(to util.Uint160, token []byte, data interface{}) (*transaction.Transaction, error){
+		tok.TransferTransaction,
+		tok.TransferUnsigned,
+	} {
+		ta.err = errors.New("")
+		_, err := fun(util.Uint160{3, 2, 1}, []byte{3, 2, 1}, nil)
+		require.Error(t, err)
+
+		ta.err = nil
+		ta.tx = &transaction.Transaction{Nonce: 100500, ValidUntilBlock: 42}
+		tx, err := fun(util.Uint160{3, 2, 1}, []byte{3, 2, 1}, nil)
+		require.NoError(t, err)
+		require.Equal(t, ta.tx, tx)
+
+		_, err = fun(util.Uint160{3, 2, 1}, []byte{3, 2, 1}, stackitem.NewMap())
+		require.Error(t, err)
+	}
+}
+
+func TestUnwrapKnownProperties(t *testing.T) {
+	_, err := UnwrapKnownProperties(stackitem.NewMap(), errors.New(""))
+	require.Error(t, err)
+
+	m, err := UnwrapKnownProperties(stackitem.NewMap(), nil)
+	require.NoError(t, err)
+	require.NotNil(t, m)
+	require.Equal(t, 0, len(m))
+
+	m, err = UnwrapKnownProperties(stackitem.NewMapWithValue([]stackitem.MapElement{
+		{Key: stackitem.Make("some"), Value: stackitem.Make("thing")},
+	}), nil)
+	require.NoError(t, err)
+	require.NotNil(t, m)
+	require.Equal(t, 0, len(m))
+
+	m, err = UnwrapKnownProperties(stackitem.NewMapWithValue([]stackitem.MapElement{
+		{Key: stackitem.Make([]stackitem.Item{}), Value: stackitem.Make("thing")},
+	}), nil)
+	require.NoError(t, err)
+	require.NotNil(t, m)
+	require.Equal(t, 0, len(m))
+
+	_, err = UnwrapKnownProperties(stackitem.NewMapWithValue([]stackitem.MapElement{
+		{Key: stackitem.Make("name"), Value: stackitem.Make([]stackitem.Item{})},
+	}), nil)
+	require.Error(t, err)
+
+	_, err = UnwrapKnownProperties(stackitem.NewMapWithValue([]stackitem.MapElement{
+		{Key: stackitem.Make("name"), Value: stackitem.Make([]byte{0xff})},
+	}), nil)
+	require.Error(t, err)
+
+	m, err = UnwrapKnownProperties(stackitem.NewMapWithValue([]stackitem.MapElement{
+		{Key: stackitem.Make("name"), Value: stackitem.Make("thing")},
+		{Key: stackitem.Make("description"), Value: stackitem.Make("good NFT")},
+	}), nil)
+	require.NoError(t, err)
+	require.NotNil(t, m)
+	require.Equal(t, 2, len(m))
+	require.Equal(t, "thing", m["name"])
+	require.Equal(t, "good NFT", m["description"])
+}

pkg/rpcclient/nep11/divisible.go

@@ -0,0 +1,157 @@
+package nep11
+
+import (
+	"fmt"
+	"math/big"
+
+	"github.com/google/uuid"
+	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
+	"github.com/nspcc-dev/neo-go/pkg/neorpc/result"
+	"github.com/nspcc-dev/neo-go/pkg/rpcclient/unwrap"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+)
+
+// DivisibleReader is a reader interface for divisible NEP-11 contract.
+type DivisibleReader struct {
+	BaseReader
+}
+
+// Divisible is a state-changing interface for divisible NEP-11 contract.
+type Divisible struct {
+	Base
+}
+
+// OwnerIterator is used for iterating over OwnerOf (for divisible NFTs) results.
+type OwnerIterator struct {
+	client   Invoker
+	session  uuid.UUID
+	iterator result.Iterator
+}
+
+// NewDivisibleReader creates an instance of DivisibleReader for a contract
+// with the given hash using the given invoker.
+func NewDivisibleReader(invoker Invoker, hash util.Uint160) *DivisibleReader {
+	return &DivisibleReader{*NewBaseReader(invoker, hash)}
+}
+
+// NewDivisible creates an instance of Divisible for a contract
+// with the given hash using the given actor.
+func NewDivisible(actor Actor, hash util.Uint160) *Divisible {
+	return &Divisible{*NewBase(actor, hash)}
+}
+
+// OwnerOf returns returns an iterator that allows to walk through all owners of
+// the given token. It depends on the server to provide proper session-based
+// iterator, but can also work with expanded one.
+func (t *DivisibleReader) OwnerOf(token []byte) (*OwnerIterator, error) {
+	sess, iter, err := unwrap.SessionIterator(t.invoker.Call(t.hash, "ownerOf", token))
+	if err != nil {
+		return nil, err
+	}
+	return &OwnerIterator{t.invoker, sess, iter}, nil
+}
+
+// OwnerOfExpanded uses the same NEP-11 method as OwnerOf, but can be useful if
+// the server used doesn't support sessions and doesn't expand iterators. It
+// creates a script that will get num of result items from the iterator right in
+// the VM and return them to you. It's only limited by VM stack and GAS available
+// for RPC invocations.
+func (t *DivisibleReader) OwnerOfExpanded(token []byte, num int) ([]util.Uint160, error) {
+	return unwrap.ArrayOfUint160(t.invoker.CallAndExpandIterator(t.hash, "ownerOf", num, token))
+}
+
+// BalanceOfD is a BalanceOf for divisible NFTs, it returns the amount of token
+// owned by a particular account.
+func (t *DivisibleReader) BalanceOfD(owner util.Uint160, token []byte) (*big.Int, error) {
+	return unwrap.BigInt(t.invoker.Call(t.hash, "balanceOf", owner, token))
+}
+
+// OwnerOf is the same as (*DivisibleReader).OwnerOf.
+func (t *Divisible) OwnerOf(token []byte) (*OwnerIterator, error) {
+	r := DivisibleReader{t.BaseReader}
+	return r.OwnerOf(token)
+}
+
+// OwnerOfExpanded is the same as (*DivisibleReader).OwnerOfExpanded.
+func (t *Divisible) OwnerOfExpanded(token []byte, num int) ([]util.Uint160, error) {
+	r := DivisibleReader{t.BaseReader}
+	return r.OwnerOfExpanded(token, num)
+}
+
+// BalanceOfD is the same as (*DivisibleReader).BalanceOfD.
+func (t *Divisible) BalanceOfD(owner util.Uint160, token []byte) (*big.Int, error) {
+	r := DivisibleReader{t.BaseReader}
+	return r.BalanceOfD(owner, token)
+}
+
+// TransferD is a divisible version of (*Base).Transfer, allowing to transfer a
+// part of NFT. It creates and sends a transaction that performs a `transfer`
+// method call using the given parameters and checks for this call result,
+// failing the transaction if it's not true. The returned values are transaction
+// hash, its ValidUntilBlock value and an error if any.
+func (t *Divisible) TransferD(from util.Uint160, to util.Uint160, amount *big.Int, id []byte, data interface{}) (util.Uint256, uint32, error) {
+	script, err := t.transferScript(from, to, amount, id, data)
+	if err != nil {
+		return util.Uint256{}, 0, err
+	}
+	return t.actor.SendRun(script)
+}
+
+// TransferDTransaction is a divisible version of (*Base).TransferTransaction,
+// allowing to transfer a part of NFT. It creates a transaction that performs a
+// `transfer` method call using the given parameters and checks for this call
+// result, failing the transaction if it's not true. This transaction is signed,
+// but not sent to the network, instead it's returned to the caller.
+func (t *Divisible) TransferDTransaction(from util.Uint160, to util.Uint160, amount *big.Int, id []byte, data interface{}) (*transaction.Transaction, error) {
+	script, err := t.transferScript(from, to, amount, id, data)
+	if err != nil {
+		return nil, err
+	}
+	return t.actor.MakeRun(script)
+}
+
+// TransferDUnsigned is a divisible version of (*Base).TransferUnsigned,
+// allowing to transfer a part of NFT. It creates a transaction that performs a
+// `transfer` method call using the given parameters and checks for this call
+// result, failing the transaction if it's not true. This transaction is not
+// signed and just returned to the caller.
+func (t *Divisible) TransferDUnsigned(from util.Uint160, to util.Uint160, amount *big.Int, id []byte, data interface{}) (*transaction.Transaction, error) {
+	script, err := t.transferScript(from, to, amount, id, data)
+	if err != nil {
+		return nil, err
+	}
+	return t.actor.MakeUnsignedRun(script, nil)
+}
+
+// Next returns the next set of elements from the iterator (up to num of them).
+// It can return less than num elements in case iterator doesn't have that many
+// or zero elements if the iterator has no more elements or the session is
+// expired.
+func (v *OwnerIterator) Next(num int) ([]util.Uint160, error) {
+	items, err := v.client.TraverseIterator(v.session, &v.iterator, num)
+	if err != nil {
+		return nil, err
+	}
+	res := make([]util.Uint160, len(items))
+	for i := range items {
+		b, err := items[i].TryBytes()
+		if err != nil {
+			return nil, fmt.Errorf("element %d is not a byte string: %w", i, err)
+		}
+		u, err := util.Uint160DecodeBytesBE(b)
+		if err != nil {
+			return nil, fmt.Errorf("element %d is not a uint160: %w", i, err)
+		}
+		res[i] = u
+	}
+	return res, nil
+}
+
+// Terminate closes the iterator session used by OwnerIterator (if it's
+// session-based).
+func (v *OwnerIterator) Terminate() error {
+	if v.iterator.ID == nil {
+		return nil
+	}
+	return v.client.TerminateSession(v.session)
+}

pkg/rpcclient/nep11/divisible_test.go

@@ -0,0 +1,218 @@
+package nep11
+
+import (
+	"errors"
+	"math/big"
+	"testing"
+
+	"github.com/google/uuid"
+	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
+	"github.com/nspcc-dev/neo-go/pkg/neorpc/result"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
+	"github.com/stretchr/testify/require"
+)
+
+func TestDivisibleBalanceOf(t *testing.T) {
+	ta := new(testAct)
+	tr := NewDivisibleReader(ta, util.Uint160{1, 2, 3})
+	tt := NewDivisible(ta, util.Uint160{1, 2, 3})
+
+	for name, fun := range map[string]func(util.Uint160, []byte) (*big.Int, error){
+		"Reader": tr.BalanceOfD,
+		"Full":   tt.BalanceOfD,
+	} {
+		t.Run(name, func(t *testing.T) {
+			ta.err = errors.New("")
+			_, err := fun(util.Uint160{3, 2, 1}, []byte{1, 2, 3})
+			require.Error(t, err)
+
+			ta.err = nil
+			ta.res = &result.Invoke{
+				State: "HALT",
+				Stack: []stackitem.Item{
+					stackitem.Make(100500),
+				},
+			}
+			bal, err := fun(util.Uint160{3, 2, 1}, []byte{1, 2, 3})
+			require.NoError(t, err)
+			require.Equal(t, big.NewInt(100500), bal)
+
+			ta.res = &result.Invoke{
+				State: "HALT",
+				Stack: []stackitem.Item{
+					stackitem.Make([]stackitem.Item{}),
+				},
+			}
+			_, err = fun(util.Uint160{3, 2, 1}, []byte{1, 2, 3})
+			require.Error(t, err)
+		})
+	}
+}
+
+func TestDivisibleOwnerOfExpanded(t *testing.T) {
+	ta := new(testAct)
+	tr := NewDivisibleReader(ta, util.Uint160{1, 2, 3})
+	tt := NewDivisible(ta, util.Uint160{1, 2, 3})
+
+	for name, fun := range map[string]func([]byte, int) ([]util.Uint160, error){
+		"Reader": tr.OwnerOfExpanded,
+		"Full":   tt.OwnerOfExpanded,
+	} {
+		t.Run(name, func(t *testing.T) {
+			ta.err = errors.New("")
+			_, err := fun([]byte{1, 2, 3}, 1)
+			require.Error(t, err)
+
+			ta.err = nil
+			ta.res = &result.Invoke{
+				State: "HALT",
+				Stack: []stackitem.Item{
+					stackitem.Make(100500),
+				},
+			}
+			_, err = fun([]byte{1, 2, 3}, 1)
+			require.Error(t, err)
+
+			h := util.Uint160{3, 2, 1}
+			ta.res = &result.Invoke{
+				State: "HALT",
+				Stack: []stackitem.Item{
+					stackitem.Make([]stackitem.Item{stackitem.Make(h.BytesBE())}),
+				},
+			}
+			owls, err := fun([]byte{1, 2, 3}, 1)
+			require.NoError(t, err)
+			require.Equal(t, []util.Uint160{h}, owls)
+		})
+	}
+}
+
+func TestDivisibleOwnerOf(t *testing.T) {
+	ta := new(testAct)
+	tr := NewDivisibleReader(ta, util.Uint160{1, 2, 3})
+	tt := NewDivisible(ta, util.Uint160{1, 2, 3})
+
+	for name, fun := range map[string]func([]byte) (*OwnerIterator, error){
+		"Reader": tr.OwnerOf,
+		"Full":   tt.OwnerOf,
+	} {
+		t.Run(name, func(t *testing.T) {
+			ta.err = errors.New("")
+			_, err := fun([]byte{1})
+			require.Error(t, err)
+
+			iid := uuid.New()
+			ta.err = nil
+			ta.res = &result.Invoke{
+				Session: uuid.New(),
+				State:   "HALT",
+				Stack: []stackitem.Item{
+					stackitem.NewInterop(result.Iterator{
+						ID: &iid,
+					}),
+				},
+			}
+			iter, err := fun([]byte{1})
+			require.NoError(t, err)
+
+			ta.res = &result.Invoke{
+				Stack: []stackitem.Item{
+					stackitem.Make([]stackitem.Item{}),
+				},
+			}
+			_, err = iter.Next(10)
+			require.Error(t, err)
+
+			ta.res = &result.Invoke{
+				Stack: []stackitem.Item{
+					stackitem.Make("not uint160"),
+				},
+			}
+			_, err = iter.Next(10)
+			require.Error(t, err)
+
+			h1 := util.Uint160{1, 2, 3}
+			h2 := util.Uint160{3, 2, 1}
+			ta.res = &result.Invoke{
+				Stack: []stackitem.Item{
+					stackitem.Make(h1.BytesBE()),
+					stackitem.Make(h2.BytesBE()),
+				},
+			}
+			vals, err := iter.Next(10)
+			require.NoError(t, err)
+			require.Equal(t, []util.Uint160{h1, h2}, vals)
+
+			ta.err = errors.New("")
+			_, err = iter.Next(1)
+			require.Error(t, err)
+
+			err = iter.Terminate()
+			require.Error(t, err)
+
+			// Value-based iterator.
+			ta.err = nil
+			ta.res = &result.Invoke{
+				State: "HALT",
+				Stack: []stackitem.Item{
+					stackitem.NewInterop(result.Iterator{
+						Values: []stackitem.Item{
+							stackitem.Make(h1.BytesBE()),
+							stackitem.Make(h2.BytesBE()),
+						},
+					}),
+				},
+			}
+			iter, err = fun([]byte{1})
+			require.NoError(t, err)
+
+			ta.err = errors.New("")
+			err = iter.Terminate()
+			require.NoError(t, err)
+		})
+	}
+}
+
+func TestDivisibleTransfer(t *testing.T) {
+	ta := new(testAct)
+	tok := NewDivisible(ta, util.Uint160{1, 2, 3})
+
+	ta.err = errors.New("")
+	_, _, err := tok.TransferD(util.Uint160{1, 2, 3}, util.Uint160{3, 2, 1}, big.NewInt(10), []byte{3, 2, 1}, nil)
+	require.Error(t, err)
+
+	ta.err = nil
+	ta.txh = util.Uint256{1, 2, 3}
+	ta.vub = 42
+	h, vub, err := tok.TransferD(util.Uint160{1, 2, 3}, util.Uint160{3, 2, 1}, big.NewInt(10), []byte{3, 2, 1}, nil)
+	require.NoError(t, err)
+	require.Equal(t, ta.txh, h)
+	require.Equal(t, ta.vub, vub)
+
+	_, _, err = tok.TransferD(util.Uint160{1, 2, 3}, util.Uint160{3, 2, 1}, big.NewInt(10), []byte{3, 2, 1}, stackitem.NewMap())
+	require.Error(t, err)
+}
+
+func TestDivisibleTransferTransaction(t *testing.T) {
+	ta := new(testAct)
+	tok := NewDivisible(ta, util.Uint160{1, 2, 3})
+
+	for _, fun := range []func(from util.Uint160, to util.Uint160, amount *big.Int, id []byte, data interface{}) (*transaction.Transaction, error){
+		tok.TransferDTransaction,
+		tok.TransferDUnsigned,
+	} {
+		ta.err = errors.New("")
+		_, err := fun(util.Uint160{1, 2, 3}, util.Uint160{3, 2, 1}, big.NewInt(10), []byte{3, 2, 1}, nil)
+		require.Error(t, err)
+
+		ta.err = nil
+		ta.tx = &transaction.Transaction{Nonce: 100500, ValidUntilBlock: 42}
+		tx, err := fun(util.Uint160{1, 2, 3}, util.Uint160{3, 2, 1}, big.NewInt(10), []byte{3, 2, 1}, nil)
+		require.NoError(t, err)
+		require.Equal(t, ta.tx, tx)
+
+		_, err = fun(util.Uint160{1, 2, 3}, util.Uint160{3, 2, 1}, big.NewInt(10), []byte{3, 2, 1}, stackitem.NewMap())
+		require.Error(t, err)
+	}
+}

pkg/rpcclient/nep11/nondivisible.go

@@ -0,0 +1,39 @@
+package nep11
+
+import (
+	"github.com/nspcc-dev/neo-go/pkg/rpcclient/unwrap"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+)
+
+// NonDivisibleReader is a reader interface for non-divisble NEP-11 contract.
+type NonDivisibleReader struct {
+	BaseReader
+}
+
+// NonDivisible is a state-changing interface for non-divisble NEP-11 contract.
+type NonDivisible struct {
+	Base
+}
+
+// NewNonDivisibleReader creates an instance of NonDivisibleReader for a contract
+// with the given hash using the given invoker.
+func NewNonDivisibleReader(invoker Invoker, hash util.Uint160) *NonDivisibleReader {
+	return &NonDivisibleReader{*NewBaseReader(invoker, hash)}
+}
+
+// NewNonDivisible creates an instance of NonDivisible for a contract
+// with the given hash using the given actor.
+func NewNonDivisible(actor Actor, hash util.Uint160) *NonDivisible {
+	return &NonDivisible{*NewBase(actor, hash)}
+}
+
+// OwnerOf returns the owner of the given NFT.
+func (t *NonDivisibleReader) OwnerOf(token []byte) (util.Uint160, error) {
+	return unwrap.Uint160(t.invoker.Call(t.hash, "ownerOf", token))
+}
+
+// OwnerOf is the same as (*NonDivisibleReader).OwnerOf.
+func (t *NonDivisible) OwnerOf(token []byte) (util.Uint160, error) {
+	r := NonDivisibleReader{t.BaseReader}
+	return r.OwnerOf(token)
+}

pkg/rpcclient/nep11/nondivisible_test.go

@@ -0,0 +1,49 @@
+package nep11
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/nspcc-dev/neo-go/pkg/neorpc/result"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
+	"github.com/stretchr/testify/require"
+)
+
+func TestNDOwnerOf(t *testing.T) {
+	ta := new(testAct)
+	tr := NewNonDivisibleReader(ta, util.Uint160{1, 2, 3})
+	tt := NewNonDivisible(ta, util.Uint160{1, 2, 3})
+
+	for name, fun := range map[string]func([]byte) (util.Uint160, error){
+		"Reader": tr.OwnerOf,
+		"Full":   tt.OwnerOf,
+	} {
+		t.Run(name, func(t *testing.T) {
+			ta.err = errors.New("")
+			_, err := fun([]byte{3, 2, 1})
+			require.Error(t, err)
+
+			ta.err = nil
+			ta.res = &result.Invoke{
+				State: "HALT",
+				Stack: []stackitem.Item{
+					stackitem.Make(100500),
+				},
+			}
+			_, err = fun([]byte{3, 2, 1})
+			require.Error(t, err)
+
+			own := util.Uint160{1, 2, 3}
+			ta.res = &result.Invoke{
+				State: "HALT",
+				Stack: []stackitem.Item{
+					stackitem.Make(own.BytesBE()),
+				},
+			}
+			owl, err := fun([]byte{3, 2, 1})
+			require.NoError(t, err)
+			require.Equal(t, own, owl)
+		})
+	}
+}

pkg/rpcclient/rpc.go

@@ -302,7 +302,7 @@ func (c *Client) GetNEP17Balances(address util.Uint160) (*result.NEP17Balances,
 }
 
 // GetNEP11Properties is a wrapper for getnep11properties RPC. We recommend using
-// NEP11Properties method instead of this to receive proper VM types and work with them.
+// nep11 package and Properties method there to receive proper VM types and work with them.
 // This method is provided mostly for the sake of completeness. For well-known
 // attributes like "description", "image", "name" and "tokenURI" it returns strings,
 // while for all others []byte (which can be nil).

pkg/services/rpcsrv/client_test.go

@@ -34,6 +34,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/rpcclient/invoker"
 	"github.com/nspcc-dev/neo-go/pkg/rpcclient/management"
 	"github.com/nspcc-dev/neo-go/pkg/rpcclient/neo"
+	"github.com/nspcc-dev/neo-go/pkg/rpcclient/nep11"
 	"github.com/nspcc-dev/neo-go/pkg/rpcclient/nep17"
 	"github.com/nspcc-dev/neo-go/pkg/rpcclient/nns"
 	"github.com/nspcc-dev/neo-go/pkg/rpcclient/oracle"
@@ -1221,20 +1222,24 @@ func TestClient_NEP11_ND(t *testing.T) {
 
 	h, err := util.Uint160DecodeStringLE(nnsContractHash)
 	require.NoError(t, err)
-	acc := testchain.PrivateKeyByID(0).GetScriptHash()
+	priv0 := testchain.PrivateKeyByID(0)
+	act, err := actor.NewSimple(c, wallet.NewAccountFromPrivateKey(priv0))
+	require.NoError(t, err)
+	n11 := nep11.NewNonDivisible(act, h)
+	acc := priv0.GetScriptHash()
 
 	t.Run("Decimals", func(t *testing.T) {
-		d, err := c.NEP11Decimals(h)
+		d, err := n11.Decimals()
 		require.NoError(t, err)
 		require.EqualValues(t, 0, d) // non-divisible
 	})
 	t.Run("TotalSupply", func(t *testing.T) {
-		s, err := c.NEP11TotalSupply(h)
+		s, err := n11.TotalSupply()
 		require.NoError(t, err)
-		require.EqualValues(t, 1, s) // the only `neo.com` of acc0
+		require.EqualValues(t, big.NewInt(1), s) // the only `neo.com` of acc0
 	})
 	t.Run("Symbol", func(t *testing.T) {
-		sym, err := c.NEP11Symbol(h)
+		sym, err := n11.Symbol()
 		require.NoError(t, err)
 		require.Equal(t, "NNS", sym)
 	})
@@ -1250,17 +1255,31 @@ func TestClient_NEP11_ND(t *testing.T) {
 		}, tok)
 	})
 	t.Run("BalanceOf", func(t *testing.T) {
-		b, err := c.NEP11BalanceOf(h, acc)
+		b, err := n11.BalanceOf(acc)
 		require.NoError(t, err)
-		require.EqualValues(t, 1, b)
+		require.EqualValues(t, big.NewInt(1), b)
 	})
 	t.Run("OwnerOf", func(t *testing.T) {
-		b, err := c.NEP11NDOwnerOf(h, []byte("neo.com"))
+		b, err := n11.OwnerOf([]byte("neo.com"))
 		require.NoError(t, err)
 		require.EqualValues(t, acc, b)
 	})
+	t.Run("Tokens", func(t *testing.T) {
+		iter, err := n11.Tokens()
+		require.NoError(t, err)
+		items, err := iter.Next(config.DefaultMaxIteratorResultItems)
+		require.NoError(t, err)
+		require.Equal(t, 1, len(items))
+		require.Equal(t, [][]byte{[]byte("neo.com")}, items)
+		require.NoError(t, iter.Terminate())
+	})
+	t.Run("TokensExpanded", func(t *testing.T) {
+		items, err := n11.TokensExpanded(config.DefaultMaxIteratorResultItems)
+		require.NoError(t, err)
+		require.Equal(t, [][]byte{[]byte("neo.com")}, items)
+	})
 	t.Run("Properties", func(t *testing.T) {
-		p, err := c.NEP11Properties(h, []byte("neo.com"))
+		p, err := n11.Properties([]byte("neo.com"))
 		require.NoError(t, err)
 		blockRegisterDomain, err := chain.GetBlock(chain.GetHeaderHash(14)) // `neo.com` domain was registered in 14th block
 		require.NoError(t, err)
@@ -1271,7 +1290,7 @@ func TestClient_NEP11_ND(t *testing.T) {
 		require.EqualValues(t, expected, p)
 	})
 	t.Run("Transfer", func(t *testing.T) {
-		_, err := c.TransferNEP11(wallet.NewAccountFromPrivateKey(testchain.PrivateKeyByID(0)), testchain.PrivateKeyByID(1).GetScriptHash(), h, "neo.com", nil, 0, nil)
+		_, _, err := n11.Transfer(testchain.PrivateKeyByID(1).GetScriptHash(), []byte("neo.com"), nil)
 		require.NoError(t, err)
 	})
 }
@@ -1285,23 +1304,28 @@ func TestClient_NEP11_D(t *testing.T) {
 	require.NoError(t, err)
 	require.NoError(t, c.Init())
 
-	priv0 := testchain.PrivateKeyByID(0).GetScriptHash()
+	pkey0 := testchain.PrivateKeyByID(0)
+	priv0 := pkey0.GetScriptHash()
 	priv1 := testchain.PrivateKeyByID(1).GetScriptHash()
 	token1ID, err := hex.DecodeString(nfsoToken1ID)
 	require.NoError(t, err)
 
+	act, err := actor.NewSimple(c, wallet.NewAccountFromPrivateKey(pkey0))
+	require.NoError(t, err)
+	n11 := nep11.NewDivisible(act, nfsoHash)
+
 	t.Run("Decimals", func(t *testing.T) {
-		d, err := c.NEP11Decimals(nfsoHash)
+		d, err := n11.Decimals()
 		require.NoError(t, err)
 		require.EqualValues(t, 2, d) // Divisible.
 	})
 	t.Run("TotalSupply", func(t *testing.T) {
-		s, err := c.NEP11TotalSupply(nfsoHash)
+		s, err := n11.TotalSupply()
 		require.NoError(t, err)
-		require.EqualValues(t, 1, s) // the only NFSO of acc0
+		require.EqualValues(t, big.NewInt(1), s) // the only NFSO of acc0
 	})
 	t.Run("Symbol", func(t *testing.T) {
-		sym, err := c.NEP11Symbol(nfsoHash)
+		sym, err := n11.Symbol()
 		require.NoError(t, err)
 		require.Equal(t, "NFSO", sym)
 	})
@@ -1317,29 +1341,31 @@ func TestClient_NEP11_D(t *testing.T) {
 		}, tok)
 	})
 	t.Run("BalanceOf", func(t *testing.T) {
-		b, err := c.NEP11BalanceOf(nfsoHash, priv0)
+		b, err := n11.BalanceOf(priv0)
 		require.NoError(t, err)
-		require.EqualValues(t, 80, b)
+		require.EqualValues(t, big.NewInt(80), b)
+	})
+	t.Run("BalanceOfD", func(t *testing.T) {
+		b, err := n11.BalanceOfD(priv0, token1ID)
+		require.NoError(t, err)
+		require.EqualValues(t, big.NewInt(80), b)
 	})
 	t.Run("OwnerOf", func(t *testing.T) {
-		sessID, iter, err := c.NEP11DOwnerOf(nfsoHash, token1ID)
+		iter, err := n11.OwnerOf(token1ID)
 		require.NoError(t, err)
-		items, err := c.TraverseIterator(sessID, *iter.ID, config.DefaultMaxIteratorResultItems)
+		items, err := iter.Next(config.DefaultMaxIteratorResultItems)
 		require.NoError(t, err)
 		require.Equal(t, 2, len(items))
-		actual1, err := util.Uint160DecodeBytesBE(items[0].Value().([]byte))
+		require.Equal(t, []util.Uint160{priv1, priv0}, items)
-		require.NoError(t, err)
+		require.NoError(t, iter.Terminate())
-		actual0, err := util.Uint160DecodeBytesBE(items[1].Value().([]byte))
-		require.NoError(t, err)
-		require.Equal(t, []util.Uint160{priv1, priv0}, []util.Uint160{actual1, actual0})
 	})
-	t.Run("UnpackedOwnerOf", func(t *testing.T) {
+	t.Run("OwnerOfExpanded", func(t *testing.T) {
-		b, err := c.NEP11DUnpackedOwnerOf(nfsoHash, token1ID)
+		b, err := n11.OwnerOfExpanded(token1ID, config.DefaultMaxIteratorResultItems)
 		require.NoError(t, err)
 		require.Equal(t, []util.Uint160{priv1, priv0}, b)
 	})
 	t.Run("Properties", func(t *testing.T) {
-		p, err := c.NEP11Properties(nfsoHash, token1ID)
+		p, err := n11.Properties(token1ID)
 		require.NoError(t, err)
 		expected := stackitem.NewMap()
 		expected.Add(stackitem.Make([]byte("name")), stackitem.NewBuffer([]byte("NeoFS Object "+base64.StdEncoding.EncodeToString(token1ID))))
@@ -1348,9 +1374,7 @@ func TestClient_NEP11_D(t *testing.T) {
 		require.EqualValues(t, expected, p)
 	})
 	t.Run("Transfer", func(t *testing.T) {
-		_, err := c.TransferNEP11D(wallet.NewAccountFromPrivateKey(testchain.PrivateKeyByID(0)),
+		_, _, err := n11.TransferD(priv0, priv1, big.NewInt(20), token1ID, nil)
-			testchain.PrivateKeyByID(1).GetScriptHash(),
-			nfsoHash, 20, token1ID, nil, 0, nil)
 		require.NoError(t, err)
 	})
 }