rpc: client.go remove duplicate code

rpc/client.go

@@ -349,6 +349,52 @@ func (c *Client) BatchCallContext(ctx context.Context, b []BatchElem) error {
 	return err
 }
 
+// Subscribe calls the "[service]_subscribe" method with the given arguments,
+// registering a subscription. Server notifications for the subscription are
+// sent to the given channel. The element type of the channel must match the
+// expected type of content returned by the subscription.
+//
+// The context argument cancels the RPC request that sets up the subscription but has no
+// effect on the subscription after subscribe has returned.
+//
+// Slow subscribers will be dropped eventually. Client buffers up to 8000 notifications
+// before considering the subscriber dead. The subscription Err channel will receive
+// ErrSubscriptionQueueOverflow. Use a sufficiently large buffer on the channel or ensure
+// that the channel usually has at least one reader to prevent this issue.
+func (c *Client) Subscribe(ctx context.Context, service string, channel interface{}, args ...interface{}) (*ClientSubscription, error) {
+	// Check type of channel first.
+	chanVal := reflect.ValueOf(channel)
+	if chanVal.Kind() != reflect.Chan || chanVal.Type().ChanDir()&reflect.SendDir == 0 {
+		panic("first argument to Subscribe must be a writable channel")
+	}
+	if chanVal.IsNil() {
+		panic("channel given to Subscribe must not be nil")
+	}
+	if c.isHTTP {
+		return nil, ErrNotificationsUnsupported
+	}
+
+	msg, err := c.newMessage(service+subscribeMethodSuffix, args...)
+	if err != nil {
+		return nil, err
+	}
+	op := &requestOp{
+		ids:  []json.RawMessage{msg.ID},
+		resp: make(chan *jsonrpcMessage),
+		sub:  newClientSubscription(c, service, chanVal),
+	}
+
+	// Send the subscription request.
+	// The arrival and validity of the response is signaled on sub.quit.
+	if err := c.send(ctx, op, msg); err != nil {
+		return nil, err
+	}
+	if _, err := op.wait(ctx); err != nil {
+		return nil, err
+	}
+	return op.sub, nil
+}
+
 // ShhSubscribe calls the "shh_subscribe" method with the given arguments,
 // registering a subscription. Server notifications for the subscription are
 // sent to the given channel. The element type of the channel must match the
@@ -362,37 +408,7 @@ func (c *Client) BatchCallContext(ctx context.Context, b []BatchElem) error {
 // ErrSubscriptionQueueOverflow. Use a sufficiently large buffer on the channel or ensure
 // that the channel usually has at least one reader to prevent this issue.
 func (c *Client) ShhSubscribe(ctx context.Context, channel interface{}, args ...interface{}) (*ClientSubscription, error) {
-	// Check type of channel first.
+	return c.Subscribe(ctx, "shh", channel, args...)
-	chanVal := reflect.ValueOf(channel)
-	if chanVal.Kind() != reflect.Chan || chanVal.Type().ChanDir()&reflect.SendDir == 0 {
-		panic("first argument to ShhSubscribe must be a writable channel")
-	}
-	if chanVal.IsNil() {
-		panic("channel given to ShhSubscribe must not be nil")
-	}
-	if c.isHTTP {
-		return nil, ErrNotificationsUnsupported
-	}
-
-	msg, err := c.newMessage("shh"+subscribeMethodSuffix, args...)
-	if err != nil {
-		return nil, err
-	}
-	op := &requestOp{
-		ids:  []json.RawMessage{msg.ID},
-		resp: make(chan *jsonrpcMessage),
-		sub:  newClientSubscription(c, "shh", chanVal),
-	}
-
-	// Send the subscription request.
-	// The arrival and validity of the response is signaled on sub.quit.
-	if err := c.send(ctx, op, msg); err != nil {
-		return nil, err
-	}
-	if _, err := op.wait(ctx); err != nil {
-		return nil, err
-	}
-	return op.sub, nil
 }
 
 // EthSubscribe calls the "eth_subscribe" method with the given arguments,
@@ -408,37 +424,7 @@ func (c *Client) ShhSubscribe(ctx context.Context, channel interface{}, args ...
 // ErrSubscriptionQueueOverflow. Use a sufficiently large buffer on the channel or ensure
 // that the channel usually has at least one reader to prevent this issue.
 func (c *Client) EthSubscribe(ctx context.Context, channel interface{}, args ...interface{}) (*ClientSubscription, error) {
-	// Check type of channel first.
+	return c.Subscribe(ctx, "eth", channel, args...)
-	chanVal := reflect.ValueOf(channel)
-	if chanVal.Kind() != reflect.Chan || chanVal.Type().ChanDir()&reflect.SendDir == 0 {
-		panic("first argument to EthSubscribe must be a writable channel")
-	}
-	if chanVal.IsNil() {
-		panic("channel given to EthSubscribe must not be nil")
-	}
-	if c.isHTTP {
-		return nil, ErrNotificationsUnsupported
-	}
-
-	msg, err := c.newMessage("eth"+subscribeMethodSuffix, args...)
-	if err != nil {
-		return nil, err
-	}
-	op := &requestOp{
-		ids:  []json.RawMessage{msg.ID},
-		resp: make(chan *jsonrpcMessage),
-		sub:  newClientSubscription(c, "eth", chanVal),
-	}
-
-	// Send the subscription request.
-	// The arrival and validity of the response is signaled on sub.quit.
-	if err := c.send(ctx, op, msg); err != nil {
-		return nil, err
-	}
-	if _, err := op.wait(ctx); err != nil {
-		return nil, err
-	}
-	return op.sub, nil
 }
 
 func (c *Client) newMessage(method string, paramsIn ...interface{}) (*jsonrpcMessage, error) {