rpc: implement getproof RPC

pkg/core/blockchain.go

@@ -13,6 +13,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
 	"github.com/nspcc-dev/neo-go/pkg/core/dao"
 	"github.com/nspcc-dev/neo-go/pkg/core/mempool"
+	"github.com/nspcc-dev/neo-go/pkg/core/mpt"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
 	"github.com/nspcc-dev/neo-go/pkg/core/storage"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
@@ -555,6 +556,12 @@ func (bc *Blockchain) getSystemFeeAmount(h util.Uint256) uint32 {
 	return sf
 }
 
+// GetStateProof returns proof of having key in the MPT with the specified root.
+func (bc *Blockchain) GetStateProof(root util.Uint256, key []byte) ([][]byte, error) {
+	tr := mpt.NewTrie(mpt.NewHashNode(root), storage.NewMemCachedStore(bc.dao.Store))
+	return tr.GetProof(key)
+}
+
 // GetStateRoot returns state root for a given height.
 func (bc *Blockchain) GetStateRoot(height uint32) (*state.MPTRootState, error) {
 	return bc.dao.GetStateRoot(height)

pkg/core/blockchainer.go

@@ -39,6 +39,7 @@ type Blockchainer interface {
 	GetNEP5Balances(util.Uint160) *state.NEP5Balances
 	GetValidators(txes ...*transaction.Transaction) ([]*keys.PublicKey, error)
 	GetScriptHashesForVerifying(*transaction.Transaction) ([]util.Uint160, error)
+	GetStateProof(root util.Uint256, key []byte) ([][]byte, error)
 	GetStateRoot(height uint32) (*state.MPTRootState, error)
 	GetStorageItem(scripthash util.Uint160, key []byte) *state.StorageItem
 	GetStorageItems(hash util.Uint160) (map[string]*state.StorageItem, error)

pkg/network/helper_test.go

@@ -108,6 +108,9 @@ func (chain testChain) GetEnrollments() ([]*state.Validator, error) {
 func (chain testChain) GetScriptHashesForVerifying(*transaction.Transaction) ([]util.Uint160, error) {
 	panic("TODO")
 }
+func (chain testChain) GetStateProof(util.Uint256, []byte) ([][]byte, error) {
+	panic("TODO")
+}
 func (chain testChain) GetStateRoot(height uint32) (*state.MPTRootState, error) {
 	panic("TODO")
 }

pkg/rpc/response/result/mpt.go

@@ -1,7 +1,81 @@
 package result
 
+import (
+	"encoding/hex"
+	"encoding/json"
+
+	"github.com/nspcc-dev/neo-go/pkg/io"
+)
+
 // StateHeight is a result of getstateheight RPC.
 type StateHeight struct {
 	BlockHeight uint32 `json:"blockHeight"`
 	StateHeight uint32 `json:"stateHeight"`
 }
+
+// ProofWithKey represens key-proof pair.
+type ProofWithKey struct {
+	Key   []byte
+	Proof [][]byte
+}
+
+// GetProof is a result of getproof RPC.
+type GetProof struct {
+	Result  ProofWithKey `json:"proof"`
+	Success bool         `json:"success"`
+}
+
+// MarshalJSON implements json.Marshaler.
+func (p *ProofWithKey) MarshalJSON() ([]byte, error) {
+	w := io.NewBufBinWriter()
+	p.EncodeBinary(w.BinWriter)
+	if w.Err != nil {
+		return nil, w.Err
+	}
+	return []byte(`"` + hex.EncodeToString(w.Bytes()) + `"`), nil
+}
+
+// EncodeBinary implements io.Serializable.
+func (p *ProofWithKey) EncodeBinary(w *io.BinWriter) {
+	w.WriteVarBytes(p.Key)
+	w.WriteVarUint(uint64(len(p.Proof)))
+	for i := range p.Proof {
+		w.WriteVarBytes(p.Proof[i])
+	}
+}
+
+// DecodeBinary implements io.Serializable.
+func (p *ProofWithKey) DecodeBinary(r *io.BinReader) {
+	p.Key = r.ReadVarBytes()
+	sz := r.ReadVarUint()
+	for i := uint64(0); i < sz; i++ {
+		p.Proof = append(p.Proof, r.ReadVarBytes())
+	}
+}
+
+// UnmarshalJSON implements json.Unmarshaler.
+func (p *ProofWithKey) UnmarshalJSON(data []byte) error {
+	var s string
+	if err := json.Unmarshal(data, &s); err != nil {
+		return err
+	}
+	return p.FromString(s)
+}
+
+// String implements fmt.Stringer.
+func (p *ProofWithKey) String() string {
+	w := io.NewBufBinWriter()
+	p.EncodeBinary(w.BinWriter)
+	return hex.EncodeToString(w.Bytes())
+}
+
+// FromString decodes p from hex-encoded string.
+func (p *ProofWithKey) FromString(s string) error {
+	rawProof, err := hex.DecodeString(s)
+	if err != nil {
+		return err
+	}
+	r := io.NewBinReaderFromBuf(rawProof)
+	p.DecodeBinary(r)
+	return r.Err
+}

pkg/rpc/response/result/mpt_test.go

@@ -0,0 +1,57 @@
+package result
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/nspcc-dev/neo-go/pkg/core/mpt"
+	"github.com/nspcc-dev/neo-go/pkg/internal/random"
+	"github.com/nspcc-dev/neo-go/pkg/internal/testserdes"
+	"github.com/nspcc-dev/neo-go/pkg/io"
+	"github.com/stretchr/testify/require"
+)
+
+func testProofWithKey() *ProofWithKey {
+	return &ProofWithKey{
+		Key: random.Bytes(10),
+		Proof: [][]byte{
+			random.Bytes(12),
+			random.Bytes(0),
+			random.Bytes(34),
+		},
+	}
+}
+
+func TestGetProof_MarshalJSON(t *testing.T) {
+	t.Run("Good", func(t *testing.T) {
+		p := &GetProof{
+			Result:  *testProofWithKey(),
+			Success: true,
+		}
+		testserdes.MarshalUnmarshalJSON(t, p, new(GetProof))
+	})
+	t.Run("Compatibility", func(t *testing.T) {
+		js := []byte(`{
+      		"proof" : "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",
+      		"success" : true
+   		}`)
+
+		var p GetProof
+		require.NoError(t, json.Unmarshal(js, &p))
+		require.Equal(t, 8, len(p.Result.Proof))
+		for i := range p.Result.Proof { // smoke test that every chunk is correctly encoded node
+			r := io.NewBinReaderFromBuf(p.Result.Proof[i])
+			var n mpt.NodeObject
+			n.DecodeBinary(r)
+			require.NoError(t, r.Err)
+			require.NotNil(t, n.Node)
+		}
+	})
+}
+
+func TestProofWithKey_EncodeString(t *testing.T) {
+	expected := testProofWithKey()
+	var actual ProofWithKey
+	require.NoError(t, actual.FromString(expected.String()))
+	require.Equal(t, expected, &actual)
+}

pkg/rpc/server/server.go

@@ -15,6 +15,7 @@ import (
 	"github.com/gorilla/websocket"
 	"github.com/nspcc-dev/neo-go/pkg/core"
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
+	"github.com/nspcc-dev/neo-go/pkg/core/mpt"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
@@ -95,6 +96,7 @@ var rpcHandlers = map[string]func(*Server, request.Params) (interface{}, *respon
 	"getpeers":             (*Server).getPeers,
 	"getrawmempool":        (*Server).getRawMempool,
 	"getrawtransaction":    (*Server).getrawtransaction,
+	"getproof":             (*Server).getProof,
 	"getstateheight":       (*Server).getStateHeight,
 	"getstateroot":         (*Server).getStateRoot,
 	"getstorage":           (*Server).getStorage,
@@ -689,6 +691,31 @@ func (s *Server) getDecimals(h util.Uint160, cache map[util.Uint160]int64) (int6
 	return d, nil
 }
 
+func (s *Server) getProof(ps request.Params) (interface{}, *response.Error) {
+	root, err := ps.Value(0).GetUint256()
+	if err != nil {
+		return nil, response.ErrInvalidParams
+	}
+	sc, err := ps.Value(1).GetUint160FromHex()
+	if err != nil {
+		return nil, response.ErrInvalidParams
+	}
+	sc = sc.Reverse()
+	key, err := ps.Value(2).GetBytesHex()
+	if err != nil {
+		return nil, response.ErrInvalidParams
+	}
+	skey := mpt.ToNeoStorageKey(append(sc.BytesBE(), key...))
+	proof, err := s.chain.GetStateProof(root, skey)
+	return &result.GetProof{
+		Result: result.ProofWithKey{
+			Key:   skey,
+			Proof: proof,
+		},
+		Success: err == nil,
+	}, nil
+}
+
 func (s *Server) getStateHeight(_ request.Params) (interface{}, *response.Error) {
 	height := s.chain.BlockHeight()
 	return &result.StateHeight{

pkg/rpc/server/server_test.go

@@ -214,6 +214,28 @@ var rpcTestCases = map[string][]rpcTestCase{
 			},
 		},
 	},
+	"getproof": {
+		{
+			name:   "no params",
+			params: `[]`,
+			fail:   true,
+		},
+		{
+			name:   "invalid root",
+			params: `["0xabcdef"]`,
+			fail:   true,
+		},
+		{
+			name:   "invalid contract",
+			params: `["0000000000000000000000000000000000000000000000000000000000000000", "0xabcdef"]`,
+			fail:   true,
+		},
+		{
+			name:   "invalid key",
+			params: `["0000000000000000000000000000000000000000000000000000000000000000", "` + testContractHash + `", "notahex"]`,
+			fail:   true,
+		},
+	},
 	"getstateheight": {
 		{
 			name:   "positive",