rpc: implement getstorage RPC

docs/rpc.md

@@ -50,7 +50,7 @@ which would yield the response:
 | `getpeers` | Yes |
 | `getrawmempool` | No (#175) |
 | `getrawtransaction` | Yes |
-| `getstorage` | No (#343) |
+| `getstorage` | Yes |
 | `gettxout` | Yes |
 | `getunspents` | Yes |
 | `getversion` | Yes |

pkg/rpc/prometheus.go

@@ -123,6 +123,14 @@ var (
 			Namespace: "neogo",
 		},
 	)
+
+	getstorageCalled = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Help:      "Number of calls to getstorage rpc endpoint",
+			Name:      "getstorage_called",
+			Namespace: "neogo",
+		},
+	)
 )
 
 func init() {
@@ -142,5 +150,6 @@ func init() {
 		gettxoutCalled,
 		getrawtransactionCalled,
 		sendrawtransactionCalled,
+		getstorageCalled,
 	)
 }

pkg/rpc/server.go

@@ -207,6 +207,10 @@ Methods:
 
 		results = peers
 
+	case "getstorage":
+		getstorageCalled.Inc()
+		results, resultsErr = s.getStorage(reqParams)
+
 	case "validateaddress":
 		validateaddressCalled.Inc()
 		param, ok := reqParams.Value(0)
@@ -282,6 +286,37 @@ Methods:
 	s.WriteResponse(req, w, results)
 }
 
+func (s *Server) getStorage(ps Params) (interface{}, error) {
+	param, ok := ps.Value(0)
+	if !ok {
+		return nil, errInvalidParams
+	}
+
+	scriptHash, err := param.GetUint160FromHex()
+	if err != nil {
+		return nil, errInvalidParams
+	}
+
+	scriptHash = scriptHash.Reverse()
+
+	param, ok = ps.Value(1)
+	if !ok {
+		return nil, errInvalidParams
+	}
+
+	key, err := param.GetBytesHex()
+	if err != nil {
+		return nil, errInvalidParams
+	}
+
+	item := s.chain.GetStorageItem(scriptHash.Reverse(), key)
+	if item == nil {
+		return nil, nil
+	}
+
+	return hex.EncodeToString(item.Value), nil
+}
+
 func (s *Server) getrawtransaction(reqParams Params) (interface{}, error) {
 	var resultsErr error
 	var results interface{}

pkg/rpc/server_test.go

@@ -2,6 +2,7 @@ package rpc
 
 import (
 	"bytes"
+	"encoding/hex"
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
@@ -75,13 +76,13 @@ var rpcTestCases = map[string][]rpcTestCase{
 	"getcontractstate": {
 		{
 			name:   "positive",
-			params: `["5ec6b374fd13e53fe60be7901a091695123ea2f0"]`,
+			params: `["1a696b32e239dd5eace3f025cac0a193a5746a27"]`,
 			result: func(e *executor) interface{} { return &GetContractStateResponce{} },
 			check: func(t *testing.T, e *executor, result interface{}) {
 				res, ok := result.(*GetContractStateResponce)
 				require.True(t, ok)
 				assert.Equal(t, byte(0), res.Result.Version)
-				assert.Equal(t, util.Uint160{0x5e, 0xc6, 0xb3, 0x74, 0xfd, 0x13, 0xe5, 0x3f, 0xe6, 0x0b, 0xe7, 0x90, 0x1a, 0x09, 0x16, 0x95, 0x12, 0x3e, 0xa2, 0xf0}, res.Result.ScriptHash)
+				assert.Equal(t, util.Uint160{0x1a, 0x69, 0x6b, 0x32, 0xe2, 0x39, 0xdd, 0x5e, 0xac, 0xe3, 0xf0, 0x25, 0xca, 0xc0, 0xa1, 0x93, 0xa5, 0x74, 0x6a, 0x27}, res.Result.ScriptHash)
 				assert.Equal(t, "0.99", res.Result.CodeVersion)
 			},
 		},
@@ -101,6 +102,48 @@ var rpcTestCases = map[string][]rpcTestCase{
 			fail:   true,
 		},
 	},
+	"getstorage": {
+		{
+			name:   "positive",
+			params: `["1a696b32e239dd5eace3f025cac0a193a5746a27", "746573746b6579"]`,
+			result: func(e *executor) interface{} { return &StringResultResponse{} },
+			check: func(t *testing.T, e *executor, result interface{}) {
+				res, ok := result.(*StringResultResponse)
+				require.True(t, ok)
+				assert.Equal(t, hex.EncodeToString([]byte("testvalue")), res.Result)
+			},
+		},
+		{
+			name:   "missing key",
+			params: `["1a696b32e239dd5eace3f025cac0a193a5746a27", "7465"]`,
+			result: func(e *executor) interface{} { return &StringResultResponse{} },
+			check: func(t *testing.T, e *executor, result interface{}) {
+				res, ok := result.(*StringResultResponse)
+				require.True(t, ok)
+				assert.Equal(t, "", res.Result)
+			},
+		},
+		{
+			name:   "no params",
+			params: `[]`,
+			fail:   true,
+		},
+		{
+			name:   "no second parameter",
+			params: `["1a696b32e239dd5eace3f025cac0a193a5746a27"]`,
+			fail:   true,
+		},
+		{
+			name:   "invalid hash",
+			params: `["notahex"]`,
+			fail:   true,
+		},
+		{
+			name:   "invalid key",
+			params: `["1a696b32e239dd5eace3f025cac0a193a5746a27", "notahex"]`,
+			fail:   true,
+		},
+	},
 	"getassetstate": {
 		{
 			name:   "positive",