From f30937c55e130b9e9a61c78ca88fcb404d5526bc Mon Sep 17 00:00:00 2001
From: Umputun <umputun@gmail.com>
Date: Fri, 21 Jun 2019 00:06:23 -0500
Subject: [PATCH] fix empty (no args) remote calls

---
 backend/app/store/remote/client.go      | 11 +++++++++--
 backend/app/store/remote/client_test.go | 12 ++++++++++++
 backend/app/store/remote/server.go      |  8 +++++++-
 3 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/backend/app/store/remote/client.go b/backend/app/store/remote/client.go
index 9e5eb796..5317ed45 100644
--- a/backend/app/store/remote/client.go
+++ b/backend/app/store/remote/client.go
@@ -25,12 +25,19 @@ func (r *Client) Call(method string, args ...interface{}) (*Response, error) {
 
 	var b []byte
 	var err error
-	if len(args) == 1 && reflect.TypeOf(args[0]).Kind() == reflect.Struct {
+
+	switch {
+	case args == nil || len(args) == 0:
+		b, err = json.Marshal(Request{Method: method, ID: atomic.AddUint64(&r.id, 1)})
+		if err != nil {
+			return nil, errors.Wrapf(err, "marshaling failed for %s", method)
+		}
+	case len(args) == 1 && reflect.TypeOf(args[0]).Kind() == reflect.Struct:
 		b, err = json.Marshal(Request{Method: method, Params: args[0], ID: atomic.AddUint64(&r.id, 1)})
 		if err != nil {
 			return nil, errors.Wrapf(err, "marshaling failed for %s", method)
 		}
-	} else {
+	default:
 		b, err = json.Marshal(Request{Method: method, Params: args, ID: atomic.AddUint64(&r.id, 1)})
 		if err != nil {
 			return nil, errors.Wrapf(err, "marshaling failed for %s", method)
diff --git a/backend/app/store/remote/client_test.go b/backend/app/store/remote/client_test.go
index 98a2c794..59799031 100644
--- a/backend/app/store/remote/client_test.go
+++ b/backend/app/store/remote/client_test.go
@@ -47,6 +47,18 @@ func TestClient_CallWithObject(t *testing.T) {
 	t.Logf("%v %T", res, res)
 }
 
+func TestClient_CallWithNoParams(t *testing.T) {
+	ts := testServer(t, `{"method":"test","id":1}`, `{"result":"12345"}`)
+	defer ts.Close()
+	c := Client{API: ts.URL, Client: http.Client{}}
+	resp, err := c.Call("test")
+	assert.NoError(t, err)
+	res := ""
+	err = json.Unmarshal(*resp.Result, &res)
+	assert.Equal(t, "12345", res)
+	t.Logf("%v %T", res, res)
+}
+
 func TestClient_CallError(t *testing.T) {
 	ts := testServer(t, `{"method":"test","params":[123,"abc"],"id":1}`, `{"error":"some error"}`)
 	defer ts.Close()
diff --git a/backend/app/store/remote/server.go b/backend/app/store/remote/server.go
index c44e4e1a..49082af3 100644
--- a/backend/app/store/remote/server.go
+++ b/backend/app/store/remote/server.go
@@ -129,7 +129,13 @@ func (s *Server) handler(w http.ResponseWriter, r *http.Request) {
 		rest.SendErrorJSON(w, r, http.StatusNotImplemented, errors.New("unsupported method"), req.Method, 0)
 		return
 	}
-	render.JSON(w, r, fn(req.ID, *req.Params))
+
+	params := json.RawMessage{}
+	if req.Params != nil {
+		params = *req.Params
+	}
+
+	render.JSON(w, r, fn(req.ID, params))
 }
 
 func (s *Server) basicAuth(h http.Handler) http.Handler {