Add RPC Server method ValidateAddress (#134)

* Add RPC Server method ValidateAddress

- implement rpc method validateaddress (https://docs.neo.org/en-us/node/cli/2.9.4/api/validateaddress.html)
- add tests
- add to README.md

* revert go.sum

* remove break

* more tests and C# errors

* simplify

* fix after master merge

pkg/rpc/README.md

@@ -88,11 +88,11 @@ which would yield the response:
 | Method  | Implemented | Required to implement |
 | ------- | ------------| --------------------- | 
 | `getblock` | Yes | - |
-| `getaccountstate` | No | Result struct & wallet functionality |
+| `getaccountstate` | Yes | - |
 | `invokescript` | No | VM |
 | `invokefunction` | No | VM |
 | `sendrawtransaction` | No | Needs to be implemented in `pkg/core/blockchain.go` |
-| `validateaddress` | No | Needs to be implemented in `pkg/core/blockchain.go` |
+| `validateaddress` | Yes | - |
 | `getblocksysfee` | No | N/A |
 | `getcontractstate` | No | Needs to be implemented in `pkg/core/blockchain.go` |
 | `getrawmempool` | No | Needs to be implemented on in `pkg/network/server.go` |

pkg/rpc/server.go

@@ -181,15 +181,21 @@ Methods:
 
 		results = peers
 
-	case "validateaddress", "getblocksysfee", "getcontractstate", "getrawmempool", "getrawtransaction", "getstorage", "submitblock", "gettxout", "invoke", "invokefunction", "invokescript", "sendrawtransaction":
+	case "getblocksysfee", "getcontractstate", "getrawmempool", "getrawtransaction", "getstorage", "submitblock", "gettxout", "invoke", "invokefunction", "invokescript", "sendrawtransaction":
 		results = "TODO"
 
+	case "validateaddress":
+		param, err := reqParams.Value(0)
+		if err != nil {
+			resultsErr = err
+			break
+		}
+		results = wrappers.ValidateAddress(param.RawValue)
+
 	case "getassetstate":
-		var err error
-		param, exists := reqParams.ValueAtAndType(0, "string")
-		if !exists {
-			err = errors.New("expected param at index 0 to be a valid string assetID parameter")
-			resultsErr = NewInvalidParamsError(err.Error(), err)
+		param, errRes := reqParams.ValueWithType(0, "string")
+		if errRes != nil {
+			resultsErr = errRes
 			break
 		}
 

pkg/rpc/server_test.go

@@ -56,7 +56,7 @@ func TestHandler(t *testing.T) {
 
 		{`{"jsonrpc": "2.0", "id": 1, "method": "getassetstate", "params": [123] }`,
 			"getassetstate_4",
-			`{"jsonrpc":"2.0","error":{"code":-32602,"message":"Invalid Params","data":"expected param at index 0 to be a valid string assetID parameter"},"id":1}`},
+			`{"jsonrpc":"2.0","error":{"code":-2146233033,"message":"One of the identified items was in an invalid format."},"id":1}`},
 
 		{`{"jsonrpc": "2.0", "id": 1, "method": "getblockhash", "params": [10] }`,
 			"getblockhash_1",
@@ -117,6 +117,34 @@ func TestHandler(t *testing.T) {
 			method:         "getaccountstate_4",
 			expectedResult: `{"jsonrpc":"2.0","error":{"code":-2146233086,"message":"Index was out of range. Must be non-negative and less than the size of the collection.\nParameter name: index"},"id":1}`,
 		},
+
+		// Good case, valid address
+		{
+			rpcCall:        `{ "jsonrpc": "2.0", "id": 1, "method": "validateaddress", "params": ["AQVh2pG732YvtNaxEGkQUei3YA4cvo7d2i"] }`,
+			method:         "validateaddress_1",
+			expectedResult: `{"jsonrpc":"2.0","result":{"address":"AQVh2pG732YvtNaxEGkQUei3YA4cvo7d2i","isvalid":true},"id":1}`,
+		},
+
+		// Bad case, invalid address
+		{
+			rpcCall:        `{ "jsonrpc": "2.0", "id": 1, "method": "validateaddress", "params": ["152f1muMCNa7goXYhYAQC61hxEgGacmncB"] }`,
+			method:         "validateaddress_2",
+			expectedResult: `{"jsonrpc":"2.0","result":{"address":"152f1muMCNa7goXYhYAQC61hxEgGacmncB","isvalid":false},"id":1}`,
+		},
+
+		// Bad case, not string
+		{
+			rpcCall:        `{ "jsonrpc": "2.0", "id": 1, "method": "validateaddress", "params": [1] }`,
+			method:         "validateaddress_3",
+			expectedResult: `{"jsonrpc":"2.0","result":{"address":1,"isvalid":false},"id":1}`,
+		},
+
+		// Bad case, empty params
+		{
+			rpcCall:        `{ "jsonrpc": "2.0", "id": 1, "method": "validateaddress", "params": [] }`,
+			method:         "validateaddress_4",
+			expectedResult: `{"jsonrpc":"2.0","error":{"code":-2146233086,"message":"Index was out of range. Must be non-negative and less than the size of the collection.\nParameter name: index"},"id":1}`,
+		},
 	}
 
 	for _, tc := range testCases {

pkg/rpc/wrappers/validate_address.go

@@ -0,0 +1,21 @@
+package wrappers
+
+import (
+	"github.com/CityOfZion/neo-go/pkg/crypto"
+)
+
+type ValidateAddressResponse struct {
+	Address interface{} `json:"address"`
+	IsValid bool        `json:"isvalid"`
+}
+
+// ValidateAddress verifies that the address is a correct NEO address
+// see https://docs.neo.org/en-us/node/cli/2.9.4/api/validateaddress.html
+func ValidateAddress(address interface{}) ValidateAddressResponse {
+	resp := ValidateAddressResponse{Address: address}
+	if address, ok := address.(string); ok {
+		_, err := crypto.Uint160DecodeAddress(address)
+		resp.IsValid = err == nil
+	}
+	return resp
+}