Merge pull request #2764 from nspcc-dev/subs-refactoring

rpc: refactor WSClient subscriptions API

docs/notifications.md

@@ -17,7 +17,7 @@ Currently supported events:
  * notification generated during execution
 
    Contents: container hash, contract hash, notification name, stack item. Filters: contract hash, notification name.
- * transaction executed
+ * transaction/persisting script executed
 
    Contents: application execution result. Filters: VM state, script container hash.
  * new/removed P2P notary request (if `P2PSigExtensions` are enabled)
@@ -34,9 +34,13 @@ Filters use conjunctional logic.
    announcing the block itself
  * transaction notifications are only announced for successful transactions
  * all announcements are being done in the same order they happen on the chain
-   First, transaction execution is announced. It is then followed by notifications
+   First, OnPersist script execution is announced followed by notifications generated
-   generated during this execution. Next, follows the transaction announcement.
+   during the script execution. After that transaction execution is announced. It is
-   Transaction announcements are ordered the same way they're in the block.
+   then followed by notifications generated during this execution. Next, follows the
+   transaction announcement. Transaction announcements are ordered the same way
+   they're in the block. After all in-block transactions announcements PostPersist
+   script execution is announced followed by notifications generated during the
+   script execution. Finally, block announcement is followed.
  * unsubscription may not cancel pending, but not yet sent events
 
 ## Subscription management
@@ -72,7 +76,7 @@ Recognized stream names:
  * `transaction_executed`
    Filter: `state` field containing `HALT` or `FAULT` string for successful
    and failed executions respectively and/or `container` field containing
-   script container hash.
+   script container (block/transaction) hash.
  * `notary_request_event`
    Filter: `sender` field containing a string with hex-encoded Uint160 (LE
    representation) for notary request's `Sender` and/or `signer` in the same
@@ -343,8 +347,10 @@ Example:
 ### `transaction_executed` notification
 
 It contains the same result as from `getapplicationlog` method in the first
-parameter and no other parameters. The only difference from `getapplicationlog` is
+parameter and no other parameters. The difference from `getapplicationlog` is
-that it always contains zero in the `contract` field.
+that it has block's or transaction's hex-encoded LE Uint256 hash in the `container`
+field instead of two separate `txid` and `blockhash` fields and a single execution
+instead of an executions array.
 
 Example:
 ```
@@ -353,11 +359,8 @@ Example:
    "params" : [
       {
          "container" : "0xe1cd5e57e721d2a2e05fb1f08721b12057b25ab1dd7fd0f33ee1639932fdfad7",
-         "executions" : [
-            {
          "trigger" : "Application",
          "gasconsumed" : "2.291",
-               "contract" : "0x0000000000000000000000000000000000000000",
          "stack" : [],
          "notifications" : [
             {
@@ -420,8 +423,6 @@ Example:
          ],
          "vmstate" : "HALT"
       }
-         ]
-      }
    ],
    "jsonrpc" : "2.0"
 }

pkg/neorpc/types.go

@@ -72,29 +72,34 @@ type (
 	}
 
 	// BlockFilter is a wrapper structure for the block event filter. It allows
-	// to filter blocks by primary index and by block index (allowing blocks since
+	// to filter blocks by primary index and/or by block index (allowing blocks
-	// the specified index).
+	// since/till the specified index inclusively). nil value treated as missing
+	// filter.
 	BlockFilter struct {
 		Primary *int    `json:"primary,omitempty"`
 		Since   *uint32 `json:"since,omitempty"`
 		Till    *uint32 `json:"till,omitempty"`
 	}
 	// TxFilter is a wrapper structure for the transaction event filter. It
-	// allows to filter transactions by senders and signers.
+	// allows to filter transactions by senders and/or signers. nil value treated
+	// as missing filter.
 	TxFilter struct {
 		Sender *util.Uint160 `json:"sender,omitempty"`
 		Signer *util.Uint160 `json:"signer,omitempty"`
 	}
 	// NotificationFilter is a wrapper structure representing a filter used for
 	// notifications generated during transaction execution. Notifications can
-	// be filtered by contract hash and by name.
+	// be filtered by contract hash and/or by name. nil value treated as missing
+	// filter.
 	NotificationFilter struct {
 		Contract *util.Uint160 `json:"contract,omitempty"`
 		Name     *string       `json:"name,omitempty"`
 	}
-	// ExecutionFilter is a wrapper structure used for transaction execution
+	// ExecutionFilter is a wrapper structure used for transaction and persisting
-	// events. It allows to choose failing or successful transactions based
+	// scripts execution events. It allows to choose failing or successful
-	// on their VM state.
+	// transactions and persisting scripts based on their VM state and/or to
+	// choose execution event with the specified container. nil value treated as
+	// missing filter.
 	ExecutionFilter struct {
 		State     *string       `json:"state,omitempty"`
 		Container *util.Uint256 `json:"container,omitempty"`

pkg/rpcclient/actor/waiter.go

@@ -6,10 +6,10 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/nspcc-dev/neo-go/pkg/core/block"
 	"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/result"
-	"github.com/nspcc-dev/neo-go/pkg/rpcclient"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract/trigger"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 )
@@ -30,6 +30,9 @@ var (
 	// ErrAwaitingNotSupported is returned from Wait method if Waiter instance
 	// doesn't support transaction awaiting.
 	ErrAwaitingNotSupported = errors.New("awaiting not supported")
+	// ErrMissedEvent is returned when RPCEventWaiter closes receiver channel
+	// which happens if missed event was received from the RPC server.
+	ErrMissedEvent = errors.New("some event was missed")
 )
 
 type (
@@ -65,8 +68,8 @@ type (
 	RPCEventWaiter interface {
 		RPCPollingWaiter
 
-		SubscribeForNewBlocksWithChan(primary *int, since *uint32, till *uint32, rcvrCh chan<- rpcclient.Notification) (string, error)
+		ReceiveBlocks(flt *neorpc.BlockFilter, rcvr chan<- *block.Block) (string, error)
-		SubscribeForTransactionExecutionsWithChan(state *string, container *util.Uint256, rcvrCh chan<- rpcclient.Notification) (string, error)
+		ReceiveExecutions(flt *neorpc.ExecutionFilter, rcvr chan<- *state.AppExecResult) (string, error)
 		Unsubscribe(id string) error
 	}
 )
@@ -223,22 +226,27 @@ func (w *EventWaiter) WaitAny(ctx context.Context, vub uint32, hashes ...util.Ui
 			}
 		}
 	}()
-	rcvr := make(chan rpcclient.Notification)
+	bRcvr := make(chan *block.Block)
+	aerRcvr := make(chan *state.AppExecResult)
 	defer func() {
 	drainLoop:
-		// Drain rcvr to avoid other notification receivers blocking.
+		// Drain receivers to avoid other notification receivers blocking.
 		for {
 			select {
-			case <-rcvr:
+			case <-bRcvr:
+			case <-aerRcvr:
 			default:
 				break drainLoop
 			}
 		}
-		close(rcvr)
+		if wsWaitErr == nil || !errors.Is(wsWaitErr, ErrMissedEvent) {
+			close(bRcvr)
+			close(aerRcvr)
+		}
 	}()
-	// Execution event follows the block event, thus wait until the block next to the VUB to be sure.
+	// Execution event precedes the block event, thus wait until the VUB-th block to be sure.
-	since := vub + 1
+	since := vub
-	blocksID, err := w.ws.SubscribeForNewBlocksWithChan(nil, &since, nil, rcvr)
+	blocksID, err := w.ws.ReceiveBlocks(&neorpc.BlockFilter{Since: &since}, bRcvr)
 	if err != nil {
 		wsWaitErr = fmt.Errorf("failed to subscribe for new blocks: %w", err)
 		return
@@ -256,7 +264,7 @@ func (w *EventWaiter) WaitAny(ctx context.Context, vub uint32, hashes ...util.Ui
 		}
 	}()
 	for _, h := range hashes {
-		txsID, err := w.ws.SubscribeForTransactionExecutionsWithChan(nil, &h, rcvr)
+		txsID, err := w.ws.ReceiveExecutions(&neorpc.ExecutionFilter{Container: &h}, aerRcvr)
 		if err != nil {
 			wsWaitErr = fmt.Errorf("failed to subscribe for execution results: %w", err)
 			return
@@ -275,27 +283,25 @@ func (w *EventWaiter) WaitAny(ctx context.Context, vub uint32, hashes ...util.Ui
 		}()
 	}
 
-	for {
 	select {
-		case ntf := <-rcvr:
+	case _, ok := <-bRcvr:
-			switch ntf.Type {
+		if !ok {
-			case neorpc.BlockEventID:
-				waitErr = ErrTxNotAccepted
-				return
-			case neorpc.ExecutionEventID:
-				res = ntf.Value.(*state.AppExecResult)
-				return
-			case neorpc.MissedEventID:
 			// We're toast, retry with non-ws client.
-				wsWaitErr = errors.New("some event was missed")
+			wsWaitErr = ErrMissedEvent
 			return
 		}
+		waitErr = ErrTxNotAccepted
+	case aer, ok := <-aerRcvr:
+		if !ok {
+			// We're toast, retry with non-ws client.
+			wsWaitErr = ErrMissedEvent
+			return
+		}
+		res = aer
 	case <-w.ws.Context().Done():
 		waitErr = fmt.Errorf("%w: %v", ErrContextDone, w.ws.Context().Err())
-			return
 	case <-ctx.Done():
 		waitErr = fmt.Errorf("%w: %v", ErrContextDone, ctx.Err())
+	}
 	return
 }
-	}
-}

pkg/rpcclient/actor/waiter_test.go

@@ -11,7 +11,6 @@ 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/result"
-	"github.com/nspcc-dev/neo-go/pkg/rpcclient"
 	"github.com/nspcc-dev/neo-go/pkg/util"
 	"github.com/stretchr/testify/require"
 )
@@ -20,20 +19,20 @@ type AwaitableRPCClient struct {
 	RPCClient
 
 	chLock     sync.RWMutex
-	subBlockCh chan<- rpcclient.Notification
+	subBlockCh chan<- *block.Block
-	subTxCh    chan<- rpcclient.Notification
+	subTxCh    chan<- *state.AppExecResult
 }
 
-func (c *AwaitableRPCClient) SubscribeForNewBlocksWithChan(primary *int, since *uint32, till *uint32, rcvrCh chan<- rpcclient.Notification) (string, error) {
+func (c *AwaitableRPCClient) ReceiveBlocks(flt *neorpc.BlockFilter, rcvr chan<- *block.Block) (string, error) {
 	c.chLock.Lock()
 	defer c.chLock.Unlock()
-	c.subBlockCh = rcvrCh
+	c.subBlockCh = rcvr
 	return "1", nil
 }
-func (c *AwaitableRPCClient) SubscribeForTransactionExecutionsWithChan(state *string, container *util.Uint256, rcvrCh chan<- rpcclient.Notification) (string, error) {
+func (c *AwaitableRPCClient) ReceiveExecutions(flt *neorpc.ExecutionFilter, rcvr chan<- *state.AppExecResult) (string, error) {
 	c.chLock.Lock()
 	defer c.chLock.Unlock()
-	c.subTxCh = rcvrCh
+	c.subTxCh = rcvr
 	return "2", nil
 }
 func (c *AwaitableRPCClient) Unsubscribe(id string) error { return nil }
@@ -163,10 +162,7 @@ func TestWSWaiter_Wait(t *testing.T) {
 	check(t, func() {
 		c.chLock.RLock()
 		defer c.chLock.RUnlock()
-		c.subBlockCh <- rpcclient.Notification{
+		c.subTxCh <- expected
-			Type:  neorpc.ExecutionEventID,
-			Value: expected,
-		}
 	})
 
 	// Missing AER after VUB.
@@ -178,9 +174,6 @@ func TestWSWaiter_Wait(t *testing.T) {
 	check(t, func() {
 		c.chLock.RLock()
 		defer c.chLock.RUnlock()
-		c.subBlockCh <- rpcclient.Notification{
+		c.subBlockCh <- &block.Block{}
-			Type:  neorpc.BlockEventID,
-			Value: &block.Block{},
-		}
 	})
 }

pkg/rpcclient/wsclient.go

@@ -34,6 +34,11 @@ type WSClient struct {
 	// WSClient to block even regular requests. This channel is not buffered.
 	// In case of protocol error or upon connection closure, this channel will
 	// be closed, so make sure to handle this.
+	//
+	// Deprecated: please, use custom channels with ReceiveBlocks, ReceiveTransactions,
+	// ReceiveExecutionNotifications, ReceiveExecutions, ReceiveNotaryRequests
+	// methods to subscribe for notifications. This field will be removed in future
+	// versions.
 	Notifications chan Notification
 
 	ws          *websocket.Conn
@@ -47,29 +52,261 @@ type WSClient struct {
 
 	subscriptionsLock sync.RWMutex
 	subscriptions     map[string]notificationReceiver
+	// receivers is a mapping from receiver channel to a set of corresponding subscription IDs.
+	// It must be accessed with subscriptionsLock taken. Its keys must be used to deliver
+	// notifications, if channel is not in the receivers list and corresponding subscription
+	// still exists, notification must not be sent.
+	receivers map[interface{}][]string
 
 	respLock     sync.RWMutex
 	respChannels map[uint64]chan *neorpc.Response
 }
 
-// notificationReceiver is a server events receiver. It stores desired notifications ID
+// notificationReceiver is an interface aimed to provide WS subscriber functionality
-// and filter and a channel used to receive matching notifications.
+// for different types of subscriptions.
-type notificationReceiver struct {
+type notificationReceiver interface {
-	typ    neorpc.EventID
+	// Comparator provides notification filtering functionality.
+	rpcevent.Comparator
+	// Receiver returns notification receiver channel.
+	Receiver() interface{}
+	// TrySend checks whether notification passes receiver filter and sends it
+	// to the underlying channel if so.
+	TrySend(ntf Notification) bool
+	// Close closes underlying receiver channel.
+	Close()
+}
+
+// blockReceiver stores information about block events subscriber.
+type blockReceiver struct {
+	filter *neorpc.BlockFilter
+	ch     chan<- *block.Block
+}
+
+// EventID implements neorpc.Comparator interface.
+func (r *blockReceiver) EventID() neorpc.EventID {
+	return neorpc.BlockEventID
+}
+
+// Filter implements neorpc.Comparator interface.
+func (r *blockReceiver) Filter() interface{} {
+	if r.filter == nil {
+		return nil
+	}
+	return *r.filter
+}
+
+// Receiver implements notificationReceiver interface.
+func (r *blockReceiver) Receiver() interface{} {
+	return r.ch
+}
+
+// TrySend implements notificationReceiver interface.
+func (r *blockReceiver) TrySend(ntf Notification) bool {
+	if rpcevent.Matches(r, ntf) {
+		r.ch <- ntf.Value.(*block.Block)
+		return true
+	}
+	return false
+}
+
+// Close implements notificationReceiver interface.
+func (r *blockReceiver) Close() {
+	close(r.ch)
+}
+
+// txReceiver stores information about transaction events subscriber.
+type txReceiver struct {
+	filter *neorpc.TxFilter
+	ch     chan<- *transaction.Transaction
+}
+
+// EventID implements neorpc.Comparator interface.
+func (r *txReceiver) EventID() neorpc.EventID {
+	return neorpc.TransactionEventID
+}
+
+// Filter implements neorpc.Comparator interface.
+func (r *txReceiver) Filter() interface{} {
+	if r.filter == nil {
+		return nil
+	}
+	return *r.filter
+}
+
+// Receiver implements notificationReceiver interface.
+func (r *txReceiver) Receiver() interface{} {
+	return r.ch
+}
+
+// TrySend implements notificationReceiver interface.
+func (r *txReceiver) TrySend(ntf Notification) bool {
+	if rpcevent.Matches(r, ntf) {
+		r.ch <- ntf.Value.(*transaction.Transaction)
+		return true
+	}
+	return false
+}
+
+// Close implements notificationReceiver interface.
+func (r *txReceiver) Close() {
+	close(r.ch)
+}
+
+// executionNotificationReceiver stores information about execution notifications subscriber.
+type executionNotificationReceiver struct {
+	filter *neorpc.NotificationFilter
+	ch     chan<- *state.ContainedNotificationEvent
+}
+
+// EventID implements neorpc.Comparator interface.
+func (r *executionNotificationReceiver) EventID() neorpc.EventID {
+	return neorpc.NotificationEventID
+}
+
+// Filter implements neorpc.Comparator interface.
+func (r *executionNotificationReceiver) Filter() interface{} {
+	if r.filter == nil {
+		return nil
+	}
+	return *r.filter
+}
+
+// Receiver implements notificationReceiver interface.
+func (r *executionNotificationReceiver) Receiver() interface{} {
+	return r.ch
+}
+
+// TrySend implements notificationReceiver interface.
+func (r *executionNotificationReceiver) TrySend(ntf Notification) bool {
+	if rpcevent.Matches(r, ntf) {
+		r.ch <- ntf.Value.(*state.ContainedNotificationEvent)
+		return true
+	}
+	return false
+}
+
+// Close implements notificationReceiver interface.
+func (r *executionNotificationReceiver) Close() {
+	close(r.ch)
+}
+
+// executionReceiver stores information about application execution results subscriber.
+type executionReceiver struct {
+	filter *neorpc.ExecutionFilter
+	ch     chan<- *state.AppExecResult
+}
+
+// EventID implements neorpc.Comparator interface.
+func (r *executionReceiver) EventID() neorpc.EventID {
+	return neorpc.ExecutionEventID
+}
+
+// Filter implements neorpc.Comparator interface.
+func (r *executionReceiver) Filter() interface{} {
+	if r.filter == nil {
+		return nil
+	}
+	return *r.filter
+}
+
+// Receiver implements notificationReceiver interface.
+func (r *executionReceiver) Receiver() interface{} {
+	return r.ch
+}
+
+// TrySend implements notificationReceiver interface.
+func (r *executionReceiver) TrySend(ntf Notification) bool {
+	if rpcevent.Matches(r, ntf) {
+		r.ch <- ntf.Value.(*state.AppExecResult)
+		return true
+	}
+	return false
+}
+
+// Close implements notificationReceiver interface.
+func (r *executionReceiver) Close() {
+	close(r.ch)
+}
+
+// notaryRequestReceiver stores information about notary requests subscriber.
+type notaryRequestReceiver struct {
+	filter *neorpc.TxFilter
+	ch     chan<- *result.NotaryRequestEvent
+}
+
+// EventID implements neorpc.Comparator interface.
+func (r *notaryRequestReceiver) EventID() neorpc.EventID {
+	return neorpc.NotaryRequestEventID
+}
+
+// Filter implements neorpc.Comparator interface.
+func (r *notaryRequestReceiver) Filter() interface{} {
+	if r.filter == nil {
+		return nil
+	}
+	return *r.filter
+}
+
+// Receiver implements notificationReceiver interface.
+func (r *notaryRequestReceiver) Receiver() interface{} {
+	return r.ch
+}
+
+// TrySend implements notificationReceiver interface.
+func (r *notaryRequestReceiver) TrySend(ntf Notification) bool {
+	if rpcevent.Matches(r, ntf) {
+		r.ch <- ntf.Value.(*result.NotaryRequestEvent)
+		return true
+	}
+	return false
+}
+
+// Close implements notificationReceiver interface.
+func (r *notaryRequestReceiver) Close() {
+	close(r.ch)
+}
+
+// naiveReceiver is a structure leaved for deprecated single channel based notifications
+// delivering.
+//
+// Deprecated: this receiver must be removed after outdated subscriptions API removal.
+type naiveReceiver struct {
+	eventID neorpc.EventID
 	filter  interface{}
 	ch      chan<- Notification
 }
 
-// EventID implements neorpc.Comparator interface and returns notification ID.
+// EventID implements neorpc.Comparator interface.
-func (r notificationReceiver) EventID() neorpc.EventID {
+func (r *naiveReceiver) EventID() neorpc.EventID {
-	return r.typ
+	return r.eventID
 }
 
-// Filter implements neorpc.Comparator interface and returns notification filter.
+// Filter implements neorpc.Comparator interface.
-func (r notificationReceiver) Filter() interface{} {
+func (r *naiveReceiver) Filter() interface{} {
 	return r.filter
 }
 
+// Receiver implements notificationReceiver interface.
+func (r *naiveReceiver) Receiver() interface{} {
+	return r.ch
+}
+
+// TrySend implements notificationReceiver interface.
+func (r *naiveReceiver) TrySend(ntf Notification) bool {
+	if rpcevent.Matches(r, ntf) {
+		r.ch <- ntf
+		return true
+	}
+	return false
+}
+
+// Close implements notificationReceiver interface.
+func (r *naiveReceiver) Close() {
+	r.ch <- Notification{
+		Type: neorpc.MissedEventID, // backwards-compatible behaviour
+	}
+}
+
 // Notification represents a server-generated notification for client subscriptions.
 // Value can be one of *block.Block, *state.AppExecResult, *state.ContainedNotificationEvent
 // *transaction.Transaction or *subscriptions.NotaryRequestEvent based on Type.
@@ -111,6 +348,9 @@ const (
 	wsWriteLimit = wsPingPeriod / 2
 )
 
+// ErrNilNotificationReceiver is returned when notification receiver channel is nil.
+var ErrNilNotificationReceiver = errors.New("nil notification receiver")
+
 // errConnClosedByUser is a WSClient error used iff the user calls (*WSClient).Close method by himself.
 var errConnClosedByUser = errors.New("connection closed by user")
 
@@ -138,6 +378,7 @@ func NewWS(ctx context.Context, endpoint string, opts Options) (*WSClient, error
 		respChannels:  make(map[uint64]chan *neorpc.Response),
 		requests:      make(chan *neorpc.Request),
 		subscriptions: make(map[string]notificationReceiver),
+		receivers:     make(map[interface{}][]string),
 	}
 
 	err = initClient(ctx, &wsc.Client, endpoint, opts)
@@ -237,13 +478,22 @@ readloop:
 					break readloop
 				}
 			}
-			ok := make(map[chan<- Notification]bool)
+			if event == neorpc.MissedEventID {
+				c.subscriptionsLock.Lock()
+				for rcvr, ids := range c.receivers {
+					c.subscriptions[ids[0]].Close()
+					delete(c.receivers, rcvr)
+				}
+				c.subscriptionsLock.Unlock()
+				continue readloop
+			}
 			c.subscriptionsLock.RLock()
-			for _, rcvr := range c.subscriptions {
 			ntf := Notification{Type: event, Value: val}
-				if (rpcevent.Matches(rcvr, ntf) || event == neorpc.MissedEventID /*missed event must be delivered to each receiver*/) && !ok[rcvr.ch] {
+			for _, ids := range c.receivers {
-					ok[rcvr.ch] = true // strictly one notification per channel
+				for _, id := range ids {
-					rcvr.ch <- ntf     // this will block other receivers
+					if c.subscriptions[id].TrySend(ntf) {
+						break // strictly one notification per channel
+					}
 				}
 			}
 			c.subscriptionsLock.RUnlock()
@@ -370,92 +620,109 @@ func (c *WSClient) performSubscription(params []interface{}, rcvr notificationRe
 	defer c.subscriptionsLock.Unlock()
 
 	c.subscriptions[resp] = rcvr
+	ch := rcvr.Receiver()
+	c.receivers[ch] = append(c.receivers[ch], resp)
 	return resp, nil
 }
 
 func (c *WSClient) performUnsubscription(id string) error {
-	var resp bool
-
 	c.subscriptionsLock.Lock()
 	defer c.subscriptionsLock.Unlock()
 
 	if _, ok := c.subscriptions[id]; !ok {
 		return errors.New("no subscription with this ID")
 	}
-	if err := c.performRequest("unsubscribe", []interface{}{id}, &resp); err != nil {
+	return c.removeSubscription(id)
-		return err
-	}
-	if !resp {
-		return errors.New("unsubscribe method returned false result")
-	}
-	delete(c.subscriptions, id)
-	return nil
 }
 
 // SubscribeForNewBlocks adds subscription for new block events to this instance
-// of the client. It can be filtered by primary consensus node index and/or block
+// of the client. It can be filtered by primary consensus node index, nil value doesn't
-// index allowing to receive blocks since the specified index only, nil value is
+// add any filters.
-// treated as missing filter.
 //
-// Deprecated: please, use SubscribeForNewBlocksWithChan. This method will be removed in future versions.
+// Deprecated: please, use ReceiveBlocks. This method will be removed in future versions.
-func (c *WSClient) SubscribeForNewBlocks(primary *int, sinceIndex, tillIndex *uint32) (string, error) {
+func (c *WSClient) SubscribeForNewBlocks(primary *int) (string, error) {
-	return c.SubscribeForNewBlocksWithChan(primary, sinceIndex, tillIndex, c.Notifications)
+	var flt *neorpc.BlockFilter
-}
+	if primary != nil {
-
+		flt = &neorpc.BlockFilter{Primary: primary}
-// SubscribeForNewBlocksWithChan registers provided channel as a receiver for the
-// new block events. Events can be filtered by primary consensus node index, nil
-// value doesn't add any filters. If the receiver channel is nil, then the default
-// Notifications channel will be used. The receiver channel must be properly read
-// and drained after usage in order not to block other notification receivers.
-func (c *WSClient) SubscribeForNewBlocksWithChan(primary *int, sinceIndex, tillIndex *uint32, rcvrCh chan<- Notification) (string, error) {
-	if rcvrCh == nil {
-		rcvrCh = c.Notifications
 	}
 	params := []interface{}{"block_added"}
-	var flt *neorpc.BlockFilter
+	if flt != nil {
-	if primary != nil || sinceIndex != nil || tillIndex != nil {
+		params = append(params, *flt)
-		flt = &neorpc.BlockFilter{Primary: primary, Since: sinceIndex, Till: tillIndex}
-		params = append(params, flt)
 	}
-	rcvr := notificationReceiver{
+	r := &naiveReceiver{
-		typ:    neorpc.BlockEventID,
+		eventID: neorpc.BlockEventID,
 		filter:  flt,
-		ch:     rcvrCh,
+		ch:      c.Notifications,
 	}
-	return c.performSubscription(params, rcvr)
+	return c.performSubscription(params, r)
+}
+
+// ReceiveBlocks registers provided channel as a receiver for the new block events.
+// Events can be filtered by the given BlockFilter, nil value doesn't add any filter.
+// The receiver channel must be properly read and drained after usage in order not
+// to block other notification receivers. If multiple subscriptions share the same
+// receiver channel, then matching notification is only sent once per channel. The
+// receiver channel will be closed by the WSClient immediately after MissedEvent is
+// received from the server; no unsubscription is performed in this case, so it's the
+// user responsibility to unsubscribe.
+func (c *WSClient) ReceiveBlocks(flt *neorpc.BlockFilter, rcvr chan<- *block.Block) (string, error) {
+	if rcvr == nil {
+		return "", ErrNilNotificationReceiver
+	}
+	params := []interface{}{"block_added"}
+	if flt != nil {
+		params = append(params, *flt)
+	}
+	r := &blockReceiver{
+		filter: flt,
+		ch:     rcvr,
+	}
+	return c.performSubscription(params, r)
 }
 
 // SubscribeForNewTransactions adds subscription for new transaction events to
 // this instance of the client. It can be filtered by the sender and/or the signer, nil
 // value is treated as missing filter.
 //
-// Deprecated: please, use SubscribeForNewTransactionsWithChan. This method will be removed in future versions.
+// Deprecated: please, use ReceiveTransactions. This method will be removed in future versions.
 func (c *WSClient) SubscribeForNewTransactions(sender *util.Uint160, signer *util.Uint160) (string, error) {
-	return c.SubscribeForNewTransactionsWithChan(sender, signer, c.Notifications)
-}
-
-// SubscribeForNewTransactionsWithChan registers provided channel as a receiver
-// for new transaction events. Events can be filtered by the sender and/or the
-// signer, nil value is treated as missing filter. If the receiver channel is nil,
-// then the default Notifications channel will be used. The receiver channel must be
-// properly read and drained after usage in order not to block other notification
-// receivers.
-func (c *WSClient) SubscribeForNewTransactionsWithChan(sender *util.Uint160, signer *util.Uint160, rcvrCh chan<- Notification) (string, error) {
-	if rcvrCh == nil {
-		rcvrCh = c.Notifications
-	}
-	params := []interface{}{"transaction_added"}
 	var flt *neorpc.TxFilter
 	if sender != nil || signer != nil {
 		flt = &neorpc.TxFilter{Sender: sender, Signer: signer}
+	}
+	params := []interface{}{"transaction_added"}
+	if flt != nil {
 		params = append(params, *flt)
 	}
-	rcvr := notificationReceiver{
+	r := &naiveReceiver{
-		typ:    neorpc.TransactionEventID,
+		eventID: neorpc.TransactionEventID,
 		filter:  flt,
-		ch:     rcvrCh,
+		ch:      c.Notifications,
 	}
-	return c.performSubscription(params, rcvr)
+	return c.performSubscription(params, r)
+}
+
+// ReceiveTransactions registers provided channel as a receiver for new transaction
+// events. Events can be filtered by the given TxFilter, nil value doesn't add any
+// filter. The receiver channel must be properly read and drained after usage in
+// order not to block other notification receivers. If multiple subscriptions share
+// the same receiver channel, then matching notification is only sent once per channel.
+// The receiver channel will be closed by the WSClient immediately after MissedEvent is
+// received from the server; no unsubscription is performed in this case, so it's the
+// user responsibility to unsubscribe.
+func (c *WSClient) ReceiveTransactions(flt *neorpc.TxFilter, rcvr chan<- *transaction.Transaction) (string, error) {
+	if rcvr == nil {
+		return "", ErrNilNotificationReceiver
+	}
+	params := []interface{}{"transaction_added"}
+	if flt != nil {
+		params = append(params, *flt)
+	}
+	r := &txReceiver{
+		filter: flt,
+		ch:     rcvr,
+	}
+	return c.performSubscription(params, r)
 }
 
 // SubscribeForExecutionNotifications adds subscription for notifications
@@ -463,74 +730,102 @@ func (c *WSClient) SubscribeForNewTransactionsWithChan(sender *util.Uint160, sig
 // filtered by the contract's hash (that emits notifications), nil value puts no such
 // restrictions.
 //
-// Deprecated: please, use SubscribeForExecutionNotificationsWithChan. This method will be removed in future versions.
+// Deprecated: please, use ReceiveExecutionNotifications. This method will be removed in future versions.
 func (c *WSClient) SubscribeForExecutionNotifications(contract *util.Uint160, name *string) (string, error) {
-	return c.SubscribeForExecutionNotificationsWithChan(contract, name, c.Notifications)
-}
-
-// SubscribeForExecutionNotificationsWithChan registers provided channel as a
-// receiver for execution events. Events can be filtered by the contract's hash
-// (that emits notifications), nil value puts no such restrictions. If the
-// receiver channel is nil, then the default Notifications channel will be used.
-// The receiver channel must be properly read and drained after usage in order
-// not to block other notification receivers.
-func (c *WSClient) SubscribeForExecutionNotificationsWithChan(contract *util.Uint160, name *string, rcvrCh chan<- Notification) (string, error) {
-	if rcvrCh == nil {
-		rcvrCh = c.Notifications
-	}
-	params := []interface{}{"notification_from_execution"}
 	var flt *neorpc.NotificationFilter
 	if contract != nil || name != nil {
 		flt = &neorpc.NotificationFilter{Contract: contract, Name: name}
+	}
+	params := []interface{}{"notification_from_execution"}
+	if flt != nil {
 		params = append(params, *flt)
 	}
-	rcvr := notificationReceiver{
+	r := &naiveReceiver{
-		typ:    neorpc.NotificationEventID,
+		eventID: neorpc.NotificationEventID,
 		filter:  flt,
-		ch:     rcvrCh,
+		ch:      c.Notifications,
 	}
-	return c.performSubscription(params, rcvr)
+	return c.performSubscription(params, r)
+}
+
+// ReceiveExecutionNotifications registers provided channel as a receiver for execution
+// events. Events can be filtered by the given NotificationFilter, nil value doesn't add
+// any filter. The receiver channel must be properly read and drained after usage in
+// order not to block other notification receivers. If multiple subscriptions share the
+// same receiver channel, then matching notification is only sent once per channel. The
+// receiver channel will be closed by the WSClient immediately after MissedEvent is
+// received from the server; no unsubscription is performed in this case, so it's the
+// user responsibility to unsubscribe.
+func (c *WSClient) ReceiveExecutionNotifications(flt *neorpc.NotificationFilter, rcvr chan<- *state.ContainedNotificationEvent) (string, error) {
+	if rcvr == nil {
+		return "", ErrNilNotificationReceiver
+	}
+	params := []interface{}{"notification_from_execution"}
+	if flt != nil {
+		params = append(params, *flt)
+	}
+	r := &executionNotificationReceiver{
+		filter: flt,
+		ch:     rcvr,
+	}
+	return c.performSubscription(params, r)
 }
 
 // SubscribeForTransactionExecutions adds subscription for application execution
 // results generated during transaction execution to this instance of the client. It can
 // be filtered by state (HALT/FAULT) to check for successful or failing
-// transactions; it can also be filtered by script container hash.
+// transactions, nil value means no filtering.
-// nil value means no filtering.
 //
-// Deprecated: please, use SubscribeForTransactionExecutionsWithChan. This method will be removed in future versions.
+// Deprecated: please, use ReceiveExecutions. This method will be removed in future versions.
-func (c *WSClient) SubscribeForTransactionExecutions(state *string, container *util.Uint256) (string, error) {
+func (c *WSClient) SubscribeForTransactionExecutions(state *string) (string, error) {
-	return c.SubscribeForTransactionExecutionsWithChan(state, container, c.Notifications)
+	var flt *neorpc.ExecutionFilter
-}
+	if state != nil {
-
+		flt = &neorpc.ExecutionFilter{State: state}
-// SubscribeForTransactionExecutionsWithChan registers provided channel as a
-// receiver for application execution result events generated during transaction
-// execution. Events can be filtered by state (HALT/FAULT) to check for successful
-// or failing transactions; it can also be filtered by script container hash.
-// nil value means no filtering. If the receiver channel is nil, then the default
-// Notifications channel will be used. The receiver channel must be properly read
-// and drained after usage in order not to block other notification receivers.
-func (c *WSClient) SubscribeForTransactionExecutionsWithChan(state *string, container *util.Uint256, rcvrCh chan<- Notification) (string, error) {
-	if rcvrCh == nil {
-		rcvrCh = c.Notifications
 	}
 	params := []interface{}{"transaction_executed"}
-	var flt *neorpc.ExecutionFilter
+	if flt != nil {
-	if state != nil || container != nil {
+		if flt.State != nil {
-		if state != nil {
+			if *flt.State != "HALT" && *flt.State != "FAULT" {
-			if *state != "HALT" && *state != "FAULT" {
 				return "", errors.New("bad state parameter")
 			}
 		}
-		flt = &neorpc.ExecutionFilter{State: state, Container: container}
 		params = append(params, *flt)
 	}
-	rcvr := notificationReceiver{
+	r := &naiveReceiver{
-		typ:    neorpc.ExecutionEventID,
+		eventID: neorpc.ExecutionEventID,
 		filter:  flt,
-		ch:     rcvrCh,
+		ch:      c.Notifications,
 	}
-	return c.performSubscription(params, rcvr)
+	return c.performSubscription(params, r)
+}
+
+// ReceiveExecutions registers provided channel as a receiver for
+// application execution result events generated during transaction execution.
+// Events can be filtered by the given ExecutionFilter, nil value doesn't add any filter.
+// The receiver channel must be properly read and drained after usage in order not
+// to block other notification receivers. If multiple subscriptions share the same
+// receiver channel, then matching notification is only sent once per channel. The
+// receiver channel will be closed by the WSClient immediately after MissedEvent is
+// received from the server; no unsubscription is performed in this case, so it's the
+// user responsibility to unsubscribe.
+func (c *WSClient) ReceiveExecutions(flt *neorpc.ExecutionFilter, rcvr chan<- *state.AppExecResult) (string, error) {
+	if rcvr == nil {
+		return "", ErrNilNotificationReceiver
+	}
+	params := []interface{}{"transaction_executed"}
+	if flt != nil {
+		if flt.State != nil {
+			if *flt.State != "HALT" && *flt.State != "FAULT" {
+				return "", errors.New("bad state parameter")
+			}
+		}
+		params = append(params, *flt)
+	}
+	r := &executionReceiver{
+		filter: flt,
+		ch:     rcvr,
+	}
+	return c.performSubscription(params, r)
 }
 
 // SubscribeForNotaryRequests adds subscription for notary request payloads
@@ -538,33 +833,47 @@ func (c *WSClient) SubscribeForTransactionExecutionsWithChan(state *string, cont
 // request sender's hash, or main tx signer's hash, nil value puts no such
 // restrictions.
 //
-// Deprecated: please, use SubscribeForNotaryRequestsWithChan. This method will be removed in future versions.
+// Deprecated: please, use ReceiveNotaryRequests. This method will be removed in future versions.
 func (c *WSClient) SubscribeForNotaryRequests(sender *util.Uint160, mainSigner *util.Uint160) (string, error) {
-	return c.SubscribeForNotaryRequestsWithChan(sender, mainSigner, c.Notifications)
+	var flt *neorpc.TxFilter
-}
+	if sender != nil || mainSigner != nil {
-
+		flt = &neorpc.TxFilter{Sender: sender, Signer: mainSigner}
-// SubscribeForNotaryRequestsWithChan registers provided channel as a receiver
-// for notary request payload addition or removal events. It can be filtered by
-// request sender's hash, or main tx signer's hash, nil value puts no such
-// restrictions. If the receiver channel is nil, then the default Notifications
-// channel will be used. The receiver channel must be properly read and drained
-// after usage in order not to block other notification receivers.
-func (c *WSClient) SubscribeForNotaryRequestsWithChan(sender *util.Uint160, mainSigner *util.Uint160, rcvrCh chan<- Notification) (string, error) {
-	if rcvrCh == nil {
-		rcvrCh = c.Notifications
 	}
 	params := []interface{}{"notary_request_event"}
-	var flt *neorpc.TxFilter
+	if flt != nil {
-	if sender != nil {
-		flt = &neorpc.TxFilter{Sender: sender, Signer: mainSigner}
 		params = append(params, *flt)
 	}
-	rcvr := notificationReceiver{
+	r := &naiveReceiver{
-		typ:    neorpc.NotaryRequestEventID,
+		eventID: neorpc.NotaryRequestEventID,
 		filter:  flt,
-		ch:     rcvrCh,
+		ch:      c.Notifications,
 	}
-	return c.performSubscription(params, rcvr)
+	return c.performSubscription(params, r)
+}
+
+// ReceiveNotaryRequests registers provided channel as a receiver for notary request
+// payload addition or removal events. Events can be filtered by the given TxFilter
+// where sender corresponds to notary request sender (the second fallback transaction
+// signer) and signer corresponds to main transaction signers. nil value doesn't add
+// any filter. The receiver channel must be properly read and drained after usage in
+// order not to block other notification receivers. If multiple subscriptions share
+// the same receiver channel, then matching notification is only sent once per channel.
+// The receiver channel will be closed by the WSClient immediately after MissedEvent
+// is received from the server; no unsubscription is performed in this case, so it's the
+// user responsibility to unsubscribe.
+func (c *WSClient) ReceiveNotaryRequests(flt *neorpc.TxFilter, rcvr chan<- *result.NotaryRequestEvent) (string, error) {
+	if rcvr == nil {
+		return "", ErrNilNotificationReceiver
+	}
+	params := []interface{}{"notary_request_event"}
+	if flt != nil {
+		params = append(params, *flt)
+	}
+	r := &notaryRequestReceiver{
+		filter: flt,
+		ch:     rcvr,
+	}
+	return c.performSubscription(params, r)
 }
 
 // Unsubscribe removes subscription for the given event stream.
@@ -578,6 +887,18 @@ func (c *WSClient) UnsubscribeAll() error {
 	defer c.subscriptionsLock.Unlock()
 
 	for id := range c.subscriptions {
+		err := c.removeSubscription(id)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// removeSubscription is internal method that removes subscription with the given
+// ID from the list of subscriptions and receivers. It must be performed under
+// subscriptions lock.
+func (c *WSClient) removeSubscription(id string) error {
 	var resp bool
 	if err := c.performRequest("unsubscribe", []interface{}{id}, &resp); err != nil {
 		return err
@@ -585,8 +906,21 @@ func (c *WSClient) UnsubscribeAll() error {
 	if !resp {
 		return errors.New("unsubscribe method returned false result")
 	}
-		delete(c.subscriptions, id)
+	rcvr := c.subscriptions[id]
+	ch := rcvr.Receiver()
+	ids := c.receivers[ch]
+	for i, rcvrID := range ids {
+		if rcvrID == id {
+			ids = append(ids[:i], ids[i+1:]...)
+			break
 		}
+	}
+	if len(ids) == 0 {
+		delete(c.receivers, ch)
+	} else {
+		c.receivers[ch] = ids
+	}
+	delete(c.subscriptions, id)
 	return nil
 }
 

pkg/rpcclient/wsclient_test.go

@@ -15,11 +15,16 @@ import (
 
 	"github.com/gorilla/websocket"
 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
+	"github.com/nspcc-dev/neo-go/pkg/core/block"
+	"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/neorpc"
+	"github.com/nspcc-dev/neo-go/pkg/neorpc/result"
 	"github.com/nspcc-dev/neo-go/pkg/network/payload"
 	"github.com/nspcc-dev/neo-go/pkg/services/rpcsrv/params"
 	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/nspcc-dev/neo-go/pkg/vm/vmstate"
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"go.uber.org/atomic"
 )
@@ -32,31 +37,26 @@ func TestWSClientClose(t *testing.T) {
 }
 
 func TestWSClientSubscription(t *testing.T) {
-	ch := make(chan Notification)
+	bCh := make(chan *block.Block)
+	txCh := make(chan *transaction.Transaction)
+	aerCh := make(chan *state.AppExecResult)
+	ntfCh := make(chan *state.ContainedNotificationEvent)
+	ntrCh := make(chan *result.NotaryRequestEvent)
 	var cases = map[string]func(*WSClient) (string, error){
 		"blocks": func(wsc *WSClient) (string, error) {
-			return wsc.SubscribeForNewBlocksWithChan(nil, nil, nil, nil)
+			return wsc.ReceiveBlocks(nil, bCh)
-		},
-		"blocks_with_custom_ch": func(wsc *WSClient) (string, error) {
-			return wsc.SubscribeForNewBlocksWithChan(nil, nil, nil, ch)
 		},
 		"transactions": func(wsc *WSClient) (string, error) {
-			return wsc.SubscribeForNewTransactionsWithChan(nil, nil, nil)
+			return wsc.ReceiveTransactions(nil, txCh)
-		},
-		"transactions_with_custom_ch": func(wsc *WSClient) (string, error) {
-			return wsc.SubscribeForNewTransactionsWithChan(nil, nil, ch)
 		},
 		"notifications": func(wsc *WSClient) (string, error) {
-			return wsc.SubscribeForExecutionNotificationsWithChan(nil, nil, nil)
+			return wsc.ReceiveExecutionNotifications(nil, ntfCh)
-		},
-		"notifications_with_custom_ch": func(wsc *WSClient) (string, error) {
-			return wsc.SubscribeForExecutionNotificationsWithChan(nil, nil, ch)
 		},
 		"executions": func(wsc *WSClient) (string, error) {
-			return wsc.SubscribeForTransactionExecutionsWithChan(nil, nil, nil)
+			return wsc.ReceiveExecutions(nil, aerCh)
 		},
-		"executions_with_custom_ch": func(wsc *WSClient) (string, error) {
+		"notary requests": func(wsc *WSClient) (string, error) {
-			return wsc.SubscribeForTransactionExecutionsWithChan(nil, nil, ch)
+			return wsc.ReceiveNotaryRequests(nil, ntrCh)
 		},
 	}
 	t.Run("good", func(t *testing.T) {
@@ -96,13 +96,13 @@ func TestWSClientUnsubscription(t *testing.T) {
 	var cases = map[string]responseCheck{
 		"good": {`{"jsonrpc": "2.0", "id": 1, "result": true}`, func(t *testing.T, wsc *WSClient) {
 			// We can't really subscribe using this stub server, so set up wsc internals.
-			wsc.subscriptions["0"] = notificationReceiver{}
+			wsc.subscriptions["0"] = &blockReceiver{}
 			err := wsc.Unsubscribe("0")
 			require.NoError(t, err)
 		}},
 		"all": {`{"jsonrpc": "2.0", "id": 1, "result": true}`, func(t *testing.T, wsc *WSClient) {
 			// We can't really subscribe using this stub server, so set up wsc internals.
-			wsc.subscriptions["0"] = notificationReceiver{}
+			wsc.subscriptions["0"] = &blockReceiver{}
 			err := wsc.UnsubscribeAll()
 			require.NoError(t, err)
 			require.Equal(t, 0, len(wsc.subscriptions))
@@ -113,13 +113,13 @@ func TestWSClientUnsubscription(t *testing.T) {
 		}},
 		"error returned": {`{"jsonrpc": "2.0", "id": 1, "error":{"code":-32602,"message":"Invalid Params"}}`, func(t *testing.T, wsc *WSClient) {
 			// We can't really subscribe using this stub server, so set up wsc internals.
-			wsc.subscriptions["0"] = notificationReceiver{}
+			wsc.subscriptions["0"] = &blockReceiver{}
 			err := wsc.Unsubscribe("0")
 			require.Error(t, err)
 		}},
 		"false returned": {`{"jsonrpc": "2.0", "id": 1, "result": false}`, func(t *testing.T, wsc *WSClient) {
 			// We can't really subscribe using this stub server, so set up wsc internals.
-			wsc.subscriptions["0"] = notificationReceiver{}
+			wsc.subscriptions["0"] = &blockReceiver{}
 			err := wsc.Unsubscribe("0")
 			require.Error(t, err)
 		}},
@@ -144,7 +144,7 @@ func TestWSClientEvents(t *testing.T) {
 		`{"jsonrpc":"2.0","method":"notification_from_execution","params":[{"container":"0xe1cd5e57e721d2a2e05fb1f08721b12057b25ab1dd7fd0f33ee1639932fdfad7","contract":"0x1b4357bff5a01bdf2a6581247cf9ed1e24629176","eventname":"contract call","state":{"type":"Array","value":[{"type":"ByteString","value":"dHJhbnNmZXI="},{"type":"Array","value":[{"type":"ByteString","value":"dpFiJB7t+XwkgWUq3xug9b9XQxs="},{"type":"ByteString","value":"MW6FEDkBnTnfwsN9bD/uGf1YCYc="},{"type":"Integer","value":"1000"}]}]}}]}`,
 		`{"jsonrpc":"2.0","method":"transaction_executed","params":[{"container":"0xf97a72b7722c109f909a8bc16c22368c5023d85828b09b127b237aace33cf099","trigger":"Application","vmstate":"HALT","gasconsumed":"6042610","stack":[],"notifications":[{"contract":"0xe65ff7b3a02d207b584a5c27057d4e9862ef01da","eventname":"contract call","state":{"type":"Array","value":[{"type":"ByteString","value":"dHJhbnNmZXI="},{"type":"Array","value":[{"type":"ByteString","value":"MW6FEDkBnTnfwsN9bD/uGf1YCYc="},{"type":"ByteString","value":"IHKCdK+vw29DoHHTKM+j5inZy7A="},{"type":"Integer","value":"123"}]}]}},{"contract":"0xe65ff7b3a02d207b584a5c27057d4e9862ef01da","eventname":"transfer","state":{"type":"Array","value":[{"type":"ByteString","value":"MW6FEDkBnTnfwsN9bD/uGf1YCYc="},{"type":"ByteString","value":"IHKCdK+vw29DoHHTKM+j5inZy7A="},{"type":"Integer","value":"123"}]}}]}]}`,
 		fmt.Sprintf(`{"jsonrpc":"2.0","method":"block_added","params":[%s]}`, b1Verbose),
-		`{"jsonrpc":"2.0","method":"event_missed","params":[]}`,
+		`{"jsonrpc":"2.0","method":"event_missed","params":[]}`, // the last one, will trigger receiver channels closing.
 	}
 	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
 		if req.URL.Path == "/ws" && req.Method == "GET" {
@@ -163,39 +163,6 @@ func TestWSClientEvents(t *testing.T) {
 			return
 		}
 	}))
-
-	t.Run("default ntf channel", func(t *testing.T) {
-		wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), Options{})
-		require.NoError(t, err)
-		wsc.getNextRequestID = getTestRequestID
-		wsc.cacheLock.Lock()
-		wsc.cache.initDone = true // Our server mock is restricted, so perform initialisation manually.
-		wsc.cache.network = netmode.UnitTestNet
-		wsc.cacheLock.Unlock()
-		// Our server mock is restricted, so perform subscriptions manually with default notifications channel.
-		wsc.subscriptionsLock.Lock()
-		wsc.subscriptions["0"] = notificationReceiver{typ: neorpc.BlockEventID, ch: wsc.Notifications}
-		wsc.subscriptions["1"] = notificationReceiver{typ: neorpc.ExecutionEventID, ch: wsc.Notifications}
-		wsc.subscriptions["2"] = notificationReceiver{typ: neorpc.NotificationEventID, ch: wsc.Notifications}
-		// MissedEvent must be delivered without subscription.
-		wsc.subscriptionsLock.Unlock()
-		for range events {
-			select {
-			case _, ok = <-wsc.Notifications:
-			case <-time.After(time.Second):
-				t.Fatal("timeout waiting for event")
-			}
-			require.True(t, ok)
-		}
-		select {
-		case _, ok = <-wsc.Notifications:
-		case <-time.After(time.Second):
-			t.Fatal("timeout waiting for event")
-		}
-		// Connection closed by server.
-		require.False(t, ok)
-	})
-	t.Run("multiple ntf channels", func(t *testing.T) {
 	wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), Options{})
 	require.NoError(t, err)
 	wsc.getNextRequestID = getTestRequestID
@@ -205,67 +172,114 @@ func TestWSClientEvents(t *testing.T) {
 	wsc.cacheLock.Unlock()
 
 	// Our server mock is restricted, so perform subscriptions manually with default notifications channel.
-		ch1 := make(chan Notification)
+	bCh1 := make(chan *block.Block)
-		ch2 := make(chan Notification)
+	bCh2 := make(chan *block.Block)
-		ch3 := make(chan Notification)
+	aerCh1 := make(chan *state.AppExecResult)
+	aerCh2 := make(chan *state.AppExecResult)
+	aerCh3 := make(chan *state.AppExecResult)
+	ntfCh := make(chan *state.ContainedNotificationEvent)
 	halt := "HALT"
 	fault := "FAULT"
 	wsc.subscriptionsLock.Lock()
-		wsc.subscriptions["0"] = notificationReceiver{typ: neorpc.BlockEventID, ch: wsc.Notifications}
+	wsc.subscriptions["0"] = &blockReceiver{ch: bCh1}
-		wsc.subscriptions["1"] = notificationReceiver{typ: neorpc.ExecutionEventID, ch: wsc.Notifications}
+	wsc.receivers[chan<- *block.Block(bCh1)] = []string{"0"}
-		wsc.subscriptions["2"] = notificationReceiver{typ: neorpc.NotificationEventID, ch: wsc.Notifications}
+	wsc.subscriptions["1"] = &blockReceiver{ch: bCh2} // two different channels subscribed for same notifications
-		wsc.subscriptions["3"] = notificationReceiver{typ: neorpc.BlockEventID, ch: ch1}
+	wsc.receivers[chan<- *block.Block(bCh2)] = []string{"1"}
-		wsc.subscriptions["4"] = notificationReceiver{typ: neorpc.NotificationEventID, ch: ch2}
+
-		wsc.subscriptions["5"] = notificationReceiver{typ: neorpc.NotificationEventID, ch: ch2} // check duplicating subscriptions
+	wsc.subscriptions["2"] = &executionNotificationReceiver{ch: ntfCh}
-		wsc.subscriptions["6"] = notificationReceiver{typ: neorpc.ExecutionEventID, filter: neorpc.ExecutionFilter{State: &halt}, ch: ch2}
+	wsc.subscriptions["3"] = &executionNotificationReceiver{ch: ntfCh} // check duplicating subscriptions
-		wsc.subscriptions["7"] = notificationReceiver{typ: neorpc.ExecutionEventID, filter: neorpc.ExecutionFilter{State: &fault}, ch: ch3}
+	wsc.receivers[chan<- *state.ContainedNotificationEvent(ntfCh)] = []string{"2", "3"}
-		// MissedEvent must be delivered without subscription.
+
+	wsc.subscriptions["4"] = &executionReceiver{ch: aerCh1}
+	wsc.receivers[chan<- *state.AppExecResult(aerCh1)] = []string{"4"}
+	wsc.subscriptions["5"] = &executionReceiver{filter: &neorpc.ExecutionFilter{State: &halt}, ch: aerCh2}
+	wsc.receivers[chan<- *state.AppExecResult(aerCh2)] = []string{"5"}
+	wsc.subscriptions["6"] = &executionReceiver{filter: &neorpc.ExecutionFilter{State: &fault}, ch: aerCh3}
+	wsc.receivers[chan<- *state.AppExecResult(aerCh3)] = []string{"6"}
+	// MissedEvent must close the channels above.
+
+	wsc.subscriptions["7"] = &naiveReceiver{eventID: neorpc.BlockEventID, ch: wsc.Notifications}
+	wsc.subscriptions["8"] = &naiveReceiver{eventID: neorpc.BlockEventID, ch: wsc.Notifications}     // check duplicating subscriptions
+	wsc.subscriptions["9"] = &naiveReceiver{eventID: neorpc.ExecutionEventID, ch: wsc.Notifications} // check different events
+	wsc.receivers[wsc.Notifications] = []string{"7", "8", "9"}
 	wsc.subscriptionsLock.Unlock()
 
 	var (
-			defaultChCnt           int
+		b1Cnt, b2Cnt                                      int
-			ch1Cnt                 int
+		aer1Cnt, aer2Cnt, aer3Cnt                         int
-			ch2Cnt                 int
+		ntfCnt                                            int
-			ch3Cnt                 int
+		defaultCount                                      int
-			expectedDefaultCnCount = len(events)
+		expectedb1Cnt, expectedb2Cnt                      = 1, 1      // single Block event
-			expectedCh1Cnt         = 1 + 1     // Block event + Missed event
+		expectedaer1Cnt, expectedaer2Cnt, expectedaer3Cnt = 2, 2, 0   // two HALTED AERs
-			expectedCh2Cnt         = 1 + 2 + 1 // Notification event + 2 Execution events + Missed event
+		expectedntfCnt                                    = 1         // single notification event
-			expectedCh3Cnt         = 1         // Missed event
+		expectedDefaultCnt                                = 1 + 2 + 1 // single Block event + two AERs + missed event
-			ntf                    Notification
+		aer                                               *state.AppExecResult
 	)
-		for i := 0; i < expectedDefaultCnCount+expectedCh1Cnt+expectedCh2Cnt+expectedCh3Cnt; i++ {
+	for b1Cnt+b2Cnt+
+		aer1Cnt+aer2Cnt+aer3Cnt+
+		ntfCnt+
+		defaultCount !=
+		expectedb1Cnt+expectedb2Cnt+
+			expectedaer1Cnt+expectedaer2Cnt+expectedaer3Cnt+
+			expectedntfCnt+
+			expectedDefaultCnt {
 		select {
-			case ntf, ok = <-wsc.Notifications:
+		case _, ok = <-bCh1:
-				defaultChCnt++
+			if ok {
-			case ntf, ok = <-ch1:
+				b1Cnt++
-				require.True(t, ntf.Type == neorpc.BlockEventID || ntf.Type == neorpc.MissedEventID, ntf.Type)
-				ch1Cnt++
-			case ntf, ok = <-ch2:
-				require.True(t, ntf.Type == neorpc.NotificationEventID || ntf.Type == neorpc.MissedEventID || ntf.Type == neorpc.ExecutionEventID)
-				ch2Cnt++
-			case ntf, ok = <-ch3:
-				require.True(t, ntf.Type == neorpc.MissedEventID)
-				ch3Cnt++
-			case <-time.After(time.Second):
-				t.Fatal("timeout waiting for event")
 			}
-			require.True(t, ok)
+		case _, ok = <-bCh2:
+			if ok {
+				b2Cnt++
+			}
+		case _, ok = <-aerCh1:
+			if ok {
+				aer1Cnt++
+			}
+		case aer, ok = <-aerCh2:
+			if ok {
+				require.Equal(t, vmstate.Halt, aer.VMState)
+				aer2Cnt++
+			}
+		case _, ok = <-aerCh3:
+			if ok {
+				aer3Cnt++
+			}
+		case _, ok = <-ntfCh:
+			if ok {
+				ntfCnt++
 			}
-		select {
 		case _, ok = <-wsc.Notifications:
-		case _, ok = <-ch1:
+			if ok {
-		case _, ok = <-ch2:
+				defaultCount++
-		case _, ok = <-ch3:
+			}
 		case <-time.After(time.Second):
 			t.Fatal("timeout waiting for event")
 		}
-		// Connection closed by server.
+	}
+	assert.Equal(t, expectedb1Cnt, b1Cnt)
+	assert.Equal(t, expectedb2Cnt, b2Cnt)
+	assert.Equal(t, expectedaer1Cnt, aer1Cnt)
+	assert.Equal(t, expectedaer2Cnt, aer2Cnt)
+	assert.Equal(t, expectedaer3Cnt, aer3Cnt)
+	assert.Equal(t, expectedntfCnt, ntfCnt)
+	assert.Equal(t, expectedDefaultCnt, defaultCount)
+
+	// Channels must be closed by server
+	_, ok = <-bCh1
+	require.False(t, ok)
+	_, ok = <-bCh2
+	require.False(t, ok)
+	_, ok = <-aerCh1
+	require.False(t, ok)
+	_, ok = <-aerCh2
+	require.False(t, ok)
+	_, ok = <-aerCh3
+	require.False(t, ok)
+	_, ok = <-ntfCh
+	require.False(t, ok)
+	_, ok = <-ntfCh
 	require.False(t, ok)
-		require.Equal(t, expectedDefaultCnCount, defaultChCnt)
-		require.Equal(t, expectedCh1Cnt, ch1Cnt)
-		require.Equal(t, expectedCh2Cnt, ch2Cnt)
-		require.Equal(t, expectedCh3Cnt, ch3Cnt)
-	})
 }
 
 func TestWSExecutionVMStateCheck(t *testing.T) {
@@ -276,12 +290,16 @@ func TestWSExecutionVMStateCheck(t *testing.T) {
 	wsc.getNextRequestID = getTestRequestID
 	require.NoError(t, wsc.Init())
 	filter := "NONE"
-	_, err = wsc.SubscribeForTransactionExecutionsWithChan(&filter, nil, nil)
+	_, err = wsc.ReceiveExecutions(&neorpc.ExecutionFilter{State: &filter}, make(chan *state.AppExecResult))
 	require.Error(t, err)
 	wsc.Close()
 }
 
 func TestWSFilteredSubscriptions(t *testing.T) {
+	bCh := make(chan *block.Block)
+	txCh := make(chan *transaction.Transaction)
+	aerCh := make(chan *state.AppExecResult)
+	ntfCh := make(chan *state.ContainedNotificationEvent)
 	var cases = []struct {
 		name       string
 		clientCode func(*testing.T, *WSClient)
@@ -290,7 +308,7 @@ func TestWSFilteredSubscriptions(t *testing.T) {
 		{"blocks primary",
 			func(t *testing.T, wsc *WSClient) {
 				primary := 3
-				_, err := wsc.SubscribeForNewBlocksWithChan(&primary, nil, nil, nil)
+				_, err := wsc.ReceiveBlocks(&neorpc.BlockFilter{Primary: &primary}, bCh)
 				require.NoError(t, err)
 			},
 			func(t *testing.T, p *params.Params) {
@@ -305,7 +323,7 @@ func TestWSFilteredSubscriptions(t *testing.T) {
 		{"blocks since",
 			func(t *testing.T, wsc *WSClient) {
 				var since uint32 = 3
-				_, err := wsc.SubscribeForNewBlocksWithChan(nil, &since, nil, nil)
+				_, err := wsc.ReceiveBlocks(&neorpc.BlockFilter{Since: &since}, bCh)
 				require.NoError(t, err)
 			},
 			func(t *testing.T, p *params.Params) {
@@ -320,7 +338,7 @@ func TestWSFilteredSubscriptions(t *testing.T) {
 		{"blocks till",
 			func(t *testing.T, wsc *WSClient) {
 				var till uint32 = 3
-				_, err := wsc.SubscribeForNewBlocksWithChan(nil, nil, &till, nil)
+				_, err := wsc.ReceiveBlocks(&neorpc.BlockFilter{Till: &till}, bCh)
 				require.NoError(t, err)
 			},
 			func(t *testing.T, p *params.Params) {
@@ -339,7 +357,11 @@ func TestWSFilteredSubscriptions(t *testing.T) {
 					primary        = 2
 					till    uint32 = 5
 				)
-				_, err := wsc.SubscribeForNewBlocksWithChan(&primary, &since, &till, nil)
+				_, err := wsc.ReceiveBlocks(&neorpc.BlockFilter{
+					Primary: &primary,
+					Since:   &since,
+					Till:    &till,
+				}, bCh)
 				require.NoError(t, err)
 			},
 			func(t *testing.T, p *params.Params) {
@@ -354,7 +376,7 @@ func TestWSFilteredSubscriptions(t *testing.T) {
 		{"transactions sender",
 			func(t *testing.T, wsc *WSClient) {
 				sender := util.Uint160{1, 2, 3, 4, 5}
-				_, err := wsc.SubscribeForNewTransactionsWithChan(&sender, nil, nil)
+				_, err := wsc.ReceiveTransactions(&neorpc.TxFilter{Sender: &sender}, txCh)
 				require.NoError(t, err)
 			},
 			func(t *testing.T, p *params.Params) {
@@ -368,7 +390,7 @@ func TestWSFilteredSubscriptions(t *testing.T) {
 		{"transactions signer",
 			func(t *testing.T, wsc *WSClient) {
 				signer := util.Uint160{0, 42}
-				_, err := wsc.SubscribeForNewTransactionsWithChan(nil, &signer, nil)
+				_, err := wsc.ReceiveTransactions(&neorpc.TxFilter{Signer: &signer}, txCh)
 				require.NoError(t, err)
 			},
 			func(t *testing.T, p *params.Params) {
@@ -383,7 +405,7 @@ func TestWSFilteredSubscriptions(t *testing.T) {
 			func(t *testing.T, wsc *WSClient) {
 				sender := util.Uint160{1, 2, 3, 4, 5}
 				signer := util.Uint160{0, 42}
-				_, err := wsc.SubscribeForNewTransactionsWithChan(&sender, &signer, nil)
+				_, err := wsc.ReceiveTransactions(&neorpc.TxFilter{Sender: &sender, Signer: &signer}, txCh)
 				require.NoError(t, err)
 			},
 			func(t *testing.T, p *params.Params) {
@@ -397,7 +419,7 @@ func TestWSFilteredSubscriptions(t *testing.T) {
 		{"notifications contract hash",
 			func(t *testing.T, wsc *WSClient) {
 				contract := util.Uint160{1, 2, 3, 4, 5}
-				_, err := wsc.SubscribeForExecutionNotificationsWithChan(&contract, nil, nil)
+				_, err := wsc.ReceiveExecutionNotifications(&neorpc.NotificationFilter{Contract: &contract}, ntfCh)
 				require.NoError(t, err)
 			},
 			func(t *testing.T, p *params.Params) {
@@ -411,7 +433,7 @@ func TestWSFilteredSubscriptions(t *testing.T) {
 		{"notifications name",
 			func(t *testing.T, wsc *WSClient) {
 				name := "my_pretty_notification"
-				_, err := wsc.SubscribeForExecutionNotificationsWithChan(nil, &name, nil)
+				_, err := wsc.ReceiveExecutionNotifications(&neorpc.NotificationFilter{Name: &name}, ntfCh)
 				require.NoError(t, err)
 			},
 			func(t *testing.T, p *params.Params) {
@@ -426,7 +448,7 @@ func TestWSFilteredSubscriptions(t *testing.T) {
 			func(t *testing.T, wsc *WSClient) {
 				contract := util.Uint160{1, 2, 3, 4, 5}
 				name := "my_pretty_notification"
-				_, err := wsc.SubscribeForExecutionNotificationsWithChan(&contract, &name, nil)
+				_, err := wsc.ReceiveExecutionNotifications(&neorpc.NotificationFilter{Contract: &contract, Name: &name}, ntfCh)
 				require.NoError(t, err)
 			},
 			func(t *testing.T, p *params.Params) {
@@ -440,7 +462,7 @@ func TestWSFilteredSubscriptions(t *testing.T) {
 		{"executions state",
 			func(t *testing.T, wsc *WSClient) {
 				state := "FAULT"
-				_, err := wsc.SubscribeForTransactionExecutionsWithChan(&state, nil, nil)
+				_, err := wsc.ReceiveExecutions(&neorpc.ExecutionFilter{State: &state}, aerCh)
 				require.NoError(t, err)
 			},
 			func(t *testing.T, p *params.Params) {
@@ -454,7 +476,7 @@ func TestWSFilteredSubscriptions(t *testing.T) {
 		{"executions container",
 			func(t *testing.T, wsc *WSClient) {
 				container := util.Uint256{1, 2, 3}
-				_, err := wsc.SubscribeForTransactionExecutionsWithChan(nil, &container, nil)
+				_, err := wsc.ReceiveExecutions(&neorpc.ExecutionFilter{Container: &container}, aerCh)
 				require.NoError(t, err)
 			},
 			func(t *testing.T, p *params.Params) {
@@ -469,7 +491,7 @@ func TestWSFilteredSubscriptions(t *testing.T) {
 			func(t *testing.T, wsc *WSClient) {
 				state := "FAULT"
 				container := util.Uint256{1, 2, 3}
-				_, err := wsc.SubscribeForTransactionExecutionsWithChan(&state, &container, nil)
+				_, err := wsc.ReceiveExecutions(&neorpc.ExecutionFilter{State: &state, Container: &container}, aerCh)
 				require.NoError(t, err)
 			},
 			func(t *testing.T, p *params.Params) {