Support ErrCh() for client

jsonrpc/client.go

@@ -56,6 +56,11 @@ func (c *Client) Close() error {
 	return c.transport.Close()
 }
 
+// ErrCh returns a chan to send errors that occurred in the client
+func (c *Client) ErrCh() chan error {
+	return c.transport.ErrCh()
+}
+
 // Call makes a jsonrpc call
 func (c *Client) Call(method string, out interface{}, params ...interface{}) error {
 	return c.transport.Call(method, out, params...)

jsonrpc/transport/http.go

@@ -27,6 +27,11 @@ func (h *HTTP) Close() error {
 	return nil
 }
 
+// ErrCh implements the transport interface
+func (h *HTTP) ErrCh() chan error {
+	return nil
+}
+
 // Call implements the transport interface
 func (h *HTTP) Call(method string, out interface{}, params ...interface{}) error {
 	// Encode json-rpc request

jsonrpc/transport/transport.go

@@ -15,6 +15,8 @@ type Transport interface {
 
 	// Close closes the transport connection if necessary
 	Close() error
+
+	ErrCh() chan error
 }
 
 // PubSubTransport is a transport that allows subscriptions

jsonrpc/transport/websocket.go

@@ -49,13 +49,15 @@ type stream struct {
 	subsLock sync.Mutex
 	subs     map[string]func(b []byte)
 
+	errCh   chan error
 	closeCh chan struct{}
 	timer   *time.Timer
 }
 
 func newStream(codec Codec) (*stream, error) {
 	w := &stream{
 		codec:   codec,
+		errCh:   make(chan error, 1),
 		closeCh: make(chan struct{}),
 		handler: map[uint64]callback{},
 		subs:    map[string]func(b []byte){},
@@ -71,6 +73,11 @@ func (s *stream) Close() error {
 	return s.codec.Close()
 }
 
+// ErrCh implements the transport interface
+func (s *stream) ErrCh() chan error {
+	return s.errCh
+}
+
 func (s *stream) incSeq() uint64 {
 	return atomic.AddUint64(&s.seq, 1)
 }
@@ -94,6 +101,10 @@ func (s *stream) listen() {
 			if !s.isClosed() {
 				// log error
 			}
+			select {
+			case s.errCh <- err:
+			default:
+			}
 			return
 		}