bring back EventSubscriber

rpc/lib/server/handlers.go

@@ -2,6 +2,7 @@ package rpcserver
 
 import (
 	"bytes"
+	"context"
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
@@ -433,8 +434,8 @@ type wsConnection struct {
 	// Send pings to server with this period. Must be less than readWait, but greater than zero.
 	pingPeriod time.Duration
 
-	// see DisconnectCallback option.
-	disconnectCallback func(remoteAddr string)
+	// object that is used to subscribe / unsubscribe from events
+	eventSub types.EventSubscriber
 }
 
 // NewWSConnection wraps websocket.Conn.
@@ -467,11 +468,12 @@ func NewWSConnection(
 	return wsc
 }
 
-// DisconnectCallback can be used optionally to set a callback, which will be
-// called upon disconnect - not Goroutine-safe.
-func DisconnectCallback(cb func(remoteAddr string)) func(*wsConnection) {
+// EventSubscriber sets object that is used to subscribe / unsubscribe from
+// events - not Goroutine-safe. If none given, default node's eventBus will be
+// used.
+func EventSubscriber(eventSub types.EventSubscriber) func(*wsConnection) {
 	return func(wsc *wsConnection) {
-		wsc.disconnectCallback = cb
+		wsc.eventSub = eventSub
 	}
 }
 
@@ -524,8 +526,9 @@ func (wsc *wsConnection) OnStart() error {
 func (wsc *wsConnection) OnStop() {
 	// Both read and write loops close the websocket connection when they exit their loops.
 	// The writeChan is never closed, to allow WriteRPCResponse() to fail.
-	if wsc.disconnectCallback != nil {
-		wsc.disconnectCallback(wsc.remoteAddr)
+
+	if wsc.eventSub != nil {
+		wsc.eventSub.UnsubscribeAll(context.TODO(), wsc.remoteAddr)
 	}
 }
 
@@ -535,6 +538,11 @@ func (wsc *wsConnection) GetRemoteAddr() string {
 	return wsc.remoteAddr
 }
 
+// GetEventSubscriber implements WSRPCConnection by returning event subscriber.
+func (wsc *wsConnection) GetEventSubscriber() types.EventSubscriber {
+	return wsc.eventSub
+}
+
 // WriteRPCResponse pushes a response to the writeChan, and blocks until it is accepted.
 // It implements WSRPCConnection. It is Goroutine-safe.
 func (wsc *wsConnection) WriteRPCResponse(resp types.RPCResponse) {

rpc/lib/types/types.go

@@ -1,6 +1,7 @@
 package rpctypes
 
 import (
+	"context"
 	"encoding/json"
 	"fmt"
 	"reflect"
@@ -9,6 +10,9 @@ import (
 	"github.com/pkg/errors"
 
 	amino "github.com/tendermint/go-amino"
+
+	tmpubsub "github.com/tendermint/tendermint/libs/pubsub"
+	tmtypes "github.com/tendermint/tendermint/types"
 )
 
 // a wrapper to emulate a sum type: jsonrpcid = string | int
@@ -237,6 +241,7 @@ type WSRPCConnection interface {
 	GetRemoteAddr() string
 	WriteRPCResponse(resp RPCResponse)
 	TryWriteRPCResponse(resp RPCResponse) bool
+	GetEventSubscriber() EventSubscriber
 	Codec() *amino.Codec
 }
 
@@ -246,6 +251,13 @@ type WSRPCContext struct {
 	WSRPCConnection
 }
 
+// EventSubscriber mirros tendermint/tendermint/types.EventBusSubscriber
+type EventSubscriber interface {
+	Subscribe(ctx context.Context, subscriber string, query tmpubsub.Query, outCapacity ...int) (tmtypes.Subscription, error)
+	Unsubscribe(ctx context.Context, subscriber string, query tmpubsub.Query) error
+	UnsubscribeAll(ctx context.Context, subscriber string) error
+}
+
 //----------------------------------------
 // SOCKETS
 //