rpc: implement getblocknotifications API

Add new RPC method to retrieve block notifications organized by trigger type.

Signed-off-by: Ricardo Prado <ricardo.prado@simpli.com.br>
Signed-off-by: Roman Khimov <roman@nspcc.ru>

docs/rpc.md

@@ -248,6 +248,11 @@ block. It can be removed in future versions, but at the moment you can use it
 to see how much GAS is burned with a particular block (because system fees are
 burned).
 
+#### `getblocknotifications` call
+
+This method returns notifications from a block organized by trigger type.
+Supports filtering by contract and event name.
+
 #### Historic calls
 
 A set of `*historic` extension methods provide the ability of interacting with

pkg/core/blockchain.go

@@ -3168,3 +3168,8 @@ func (bc *Blockchain) GetStoragePrice() int64 {
 	}
 	return bc.contracts.Policy.GetStoragePriceInternal(bc.dao)
 }
+
+// GetTrimmedBlock returns a block with only the header and transaction hashes.
+func (bc *Blockchain) GetTrimmedBlock(hash util.Uint256) (*block.Block, error) {
+	return bc.dao.GetBlock(hash)
+}

pkg/neorpc/result/block_notifications.go

@@ -0,0 +1,12 @@
+package result
+
+import (
+	"github.com/nspcc-dev/neo-go/pkg/core/state"
+)
+
+// BlockNotifications represents notifications from a block organized by trigger type.
+type BlockNotifications struct {
+	PrePersistNotifications  []state.ContainedNotificationEvent `json:"prepersist,omitempty"`
+	TxNotifications          []state.ContainedNotificationEvent `json:"transactions,omitempty"`
+	PostPersistNotifications []state.ContainedNotificationEvent `json:"postpersist,omitempty"`
+}

pkg/rpcclient/rpc.go

@@ -972,3 +972,12 @@ func (c *Client) GetRawNotaryPool() (*result.RawNotaryPool, error) {
 	}
 	return resp, nil
 }
+
+// GetBlockNotifications returns notifications from a block organized by trigger type.
+func (c *Client) GetBlockNotifications(blockHash util.Uint256, filters ...*neorpc.NotificationFilter) (*result.BlockNotifications, error) {
+	var resp = &result.BlockNotifications{}
+	if err := c.performRequest("getblocknotifications", []any{blockHash.StringLE(), filters}, resp); err != nil {
+		return nil, err
+	}
+	return resp, nil
+}

pkg/services/rpcsrv/notification_comparator.go

@@ -0,0 +1,65 @@
+package rpcsrv
+
+import (
+	"github.com/nspcc-dev/neo-go/pkg/core/state"
+	"github.com/nspcc-dev/neo-go/pkg/neorpc"
+	"github.com/nspcc-dev/neo-go/pkg/neorpc/rpcevent"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/vm/vmstate"
+)
+
+// notificationEventComparator is a comparator for notification events.
+type notificationEventComparator struct {
+	filter neorpc.SubscriptionFilter
+}
+
+// EventID returns the event ID for the notification event comparator.
+func (s notificationEventComparator) EventID() neorpc.EventID {
+	return neorpc.NotificationEventID
+}
+
+// Filter returns the filter for the notification event comparator.
+func (c notificationEventComparator) Filter() neorpc.SubscriptionFilter {
+	return c.filter
+}
+
+// notificationEventContainer is a container for a notification event.
+type notificationEventContainer struct {
+	ntf *state.ContainedNotificationEvent
+}
+
+// EventID returns the event ID for the notification event container.
+func (c notificationEventContainer) EventID() neorpc.EventID {
+	return neorpc.NotificationEventID
+}
+
+// EventPayload returns the payload for the notification event container.
+func (c notificationEventContainer) EventPayload() any {
+	return c.ntf
+}
+
+func processAppExecResults(aers []state.AppExecResult, filter *neorpc.NotificationFilter) []state.ContainedNotificationEvent {
+	var notifications []state.ContainedNotificationEvent
+	for _, aer := range aers {
+		if aer.VMState == vmstate.Halt {
+			notifications = append(notifications, filterEvents(aer.Events, aer.Container, filter)...)
+		}
+	}
+	return notifications
+}
+
+func filterEvents(events []state.NotificationEvent, container util.Uint256, filter *neorpc.NotificationFilter) []state.ContainedNotificationEvent {
+	var notifications []state.ContainedNotificationEvent
+	for _, evt := range events {
+		ntf := state.ContainedNotificationEvent{
+			Container:         container,
+			NotificationEvent: evt,
+		}
+		if filter == nil || rpcevent.Matches(&notificationEventComparator{
+			filter: *filter,
+		}, &notificationEventContainer{ntf: &ntf}) {
+			notifications = append(notifications, ntf)
+		}
+	}
+	return notifications
+}

pkg/services/rpcsrv/server.go

@@ -112,6 +112,7 @@ type (
 		VerifyWitness(util.Uint160, hash.Hashable, *transaction.Witness, int64) (int64, error)
 		mempool.Feer // fee interface
 		ContractStorageSeeker
+		GetTrimmedBlock(hash util.Uint256) (*block.Block, error)
 	}
 
 	// ContractStorageSeeker is the interface `findstorage*` handlers need to be able to
@@ -219,6 +220,7 @@ var rpcHandlers = map[string]func(*Server, params.Params) (any, *neorpc.Error){
 	"getblockhash":                 (*Server).getBlockHash,
 	"getblockheader":               (*Server).getBlockHeader,
 	"getblockheadercount":          (*Server).getBlockHeaderCount,
+	"getblocknotifications":        (*Server).getBlockNotifications,
 	"getblocksysfee":               (*Server).getBlockSysFee,
 	"getcandidates":                (*Server).getCandidates,
 	"getcommittee":                 (*Server).getCommittee,
@@ -3202,3 +3204,51 @@ func (s *Server) getRawNotaryTransaction(reqParams params.Params) (any, *neorpc.
 	}
 	return tx.Bytes(), nil
 }
+
+// getBlockNotifications returns notifications from a specific block with optional filtering.
+func (s *Server) getBlockNotifications(reqParams params.Params) (any, *neorpc.Error) {
+	param := reqParams.Value(0)
+	hash, respErr := s.blockHashFromParam(param)
+	if respErr != nil {
+		return nil, respErr
+	}
+
+	block, err := s.chain.GetTrimmedBlock(hash)
+	if err != nil {
+		return nil, neorpc.ErrUnknownBlock
+	}
+
+	var filter *neorpc.NotificationFilter
+	if len(reqParams) > 1 {
+		filter = new(neorpc.NotificationFilter)
+		err := json.Unmarshal(reqParams[1].RawMessage, filter)
+		if err != nil {
+			return nil, neorpc.WrapErrorWithData(neorpc.ErrInvalidParams, fmt.Sprintf("invalid filter: %s", err))
+		}
+		if err := filter.IsValid(); err != nil {
+			return nil, neorpc.WrapErrorWithData(neorpc.ErrInvalidParams, fmt.Sprintf("invalid filter: %s", err))
+		}
+	}
+
+	notifications := &result.BlockNotifications{}
+
+	aers, err := s.chain.GetAppExecResults(block.Hash(), trigger.OnPersist)
+	if err == nil && len(aers) > 0 {
+		notifications.PrePersistNotifications = processAppExecResults([]state.AppExecResult{aers[0]}, filter)
+	}
+
+	for _, txHash := range block.Transactions {
+		aers, err := s.chain.GetAppExecResults(txHash.Hash(), trigger.Application)
+		if err != nil {
+			return nil, neorpc.NewInternalServerError("failed to get app exec results")
+		}
+		notifications.TxNotifications = append(notifications.TxNotifications, processAppExecResults(aers, filter)...)
+	}
+
+	aers, err = s.chain.GetAppExecResults(block.Hash(), trigger.PostPersist)
+	if err == nil && len(aers) > 0 {
+		notifications.PostPersistNotifications = processAppExecResults([]state.AppExecResult{aers[0]}, filter)
+	}
+
+	return notifications, nil
+}

pkg/services/rpcsrv/server_test.go

@@ -31,6 +31,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/core/block"
 	"github.com/nspcc-dev/neo-go/pkg/core/fee"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop/interopnames"
+	"github.com/nspcc-dev/neo-go/pkg/core/native/nativehashes"
 	"github.com/nspcc-dev/neo-go/pkg/core/native/nativenames"
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
 	"github.com/nspcc-dev/neo-go/pkg/core/storage/dboper"
@@ -2274,6 +2275,50 @@ var rpcTestCases = map[string][]rpcTestCase{
 			errCode: neorpc.InvalidParamsCode,
 		},
 	},
+	"getblocknotifications": {
+		{
+			name:   "positive",
+			params: `["` + genesisBlockHash + `"]`,
+			result: func(e *executor) any { return &result.BlockNotifications{} },
+			check: func(t *testing.T, e *executor, acc any) {
+				res, ok := acc.(*result.BlockNotifications)
+				require.True(t, ok)
+				require.NotNil(t, res)
+			},
+		},
+		{
+			name:   "positive with filter",
+			params: `["` + genesisBlockHash + `", {"contract":"` + nativehashes.NeoToken.StringLE() + `", "name":"Transfer"}]`,
+			result: func(e *executor) any { return &result.BlockNotifications{} },
+			check: func(t *testing.T, e *executor, acc any) {
+				res, ok := acc.(*result.BlockNotifications)
+				require.True(t, ok)
+				require.NotNil(t, res)
+				for _, ne := range res.TxNotifications {
+					require.Equal(t, nativehashes.NeoToken, ne.ScriptHash)
+					require.Equal(t, "Transfer", ne.Name)
+				}
+			},
+		},
+		{
+			name:    "invalid hash",
+			params:  `["invalid"]`,
+			fail:    true,
+			errCode: neorpc.InvalidParamsCode,
+		},
+		{
+			name:    "unknown block",
+			params:  `["` + util.Uint256{}.StringLE() + `"]`,
+			fail:    true,
+			errCode: neorpc.ErrUnknownBlockCode,
+		},
+		{
+			name:    "invalid filter",
+			params:  `["` + genesisBlockHash + `", {"contract":"invalid"}]`,
+			fail:    true,
+			errCode: neorpc.InvalidParamsCode,
+		},
+	},
 }
 
 func TestRPC(t *testing.T) {