RPC server handle null return value correctly

json_rpc/client.nim

@@ -96,10 +96,11 @@ proc processMessage*(client: RpcClient, line: string): Result[void, string] =
       requestFut.fail(newException(JsonRpcError, error))
       return ok()
 
-    if response.result.isNone:
+    # Up to this point, the result should contains something    
+    if response.result.string.len == 0:
       return err("missing or invalid response result")
 
-    requestFut.complete(response.result.get)
+    requestFut.complete(response.result)
     return ok()
 
   except CatchableError as exc:

json_rpc/private/jrpc_sys.nim

@@ -103,7 +103,7 @@ type
   ResponseRx* = object
     jsonrpc*: results.Opt[JsonRPC2]
     id*     : results.Opt[RequestId]
-    result* : results.Opt[JsonString]
+    result* : JsonString
     error*  : results.Opt[ResponseError]
 
   ReBatchKind* = enum

tests/test_callsigs.nim

@@ -18,6 +18,13 @@ template sourceDir: string = currentSourcePath.rsplit(DirSep, 1)[0]
 
 type
   Variant = int | bool | string
+  RefObject = ref object
+    name: string
+
+template derefType(T: type): untyped =
+  typeof(T()[])
+
+derefType(RefObject).useDefaultSerializationIn JrpcConv
 
 createRpcSigs(RpcClient, sourceDir & "/private/file_callsigs.nim")
 
@@ -33,6 +40,7 @@ createRpcSigsFromNim(RpcClient):
   proc get_Name(id: int): string
   proc getJsonString(name: string): JsonString
   proc getVariant(id: Variant): bool
+  proc getRefObject(shouldNull: bool): RefObject
 
 proc installHandlers(s: RpcServer) =
   s.rpc("shh_uninstallFilter") do(id: int) -> bool:
@@ -78,6 +86,10 @@ proc installHandlers(s: RpcServer) =
       return "moo"
     return "meow"
 
+  s.rpc("getRefObject") do(shouldNull: bool) -> Refobject:
+    if shouldNull: return nil
+    return RefObject(name: "meow")
+
 suite "test callsigs":
   var server = newRpcSocketServer(["127.0.0.1:0"])
   server.installHandlers()
@@ -130,5 +142,13 @@ suite "test callsigs":
       let res4 = waitFor client.getVariant(33)
       check res4 == true
 
+  test "Handle null return value correctly":
+    let res = waitFor client.getRefObject(true)
+    check res.isNil
+
+    let res2 = waitFor client.getRefObject(false)
+    check res2.isNil.not
+    check res2.name == "meow"
+
   server.stop()
   waitFor server.closeWait()

tests/test_jrpc_sys.nim

@@ -174,8 +174,8 @@ suite "jrpc_sys conversion":
       rx.jsonrpc.isSome
       rx.id.isSome
       rx.id.get.num == 777
-      rx.result.isSome
-      rx.result.get == JsonString("true")
+      rx.result.string.len > 0
+      rx.result == JsonString("true")
       rx.error.isNone
 
   test "ResponseTx -> ResponseRx: id(string), err: nodata":
@@ -186,7 +186,7 @@ suite "jrpc_sys conversion":
       rx.jsonrpc.isSome
       rx.id.isSome
       rx.id.get.str == "gum"
-      rx.result.isNone
+      rx.result.string.len == 0
       rx.error.isSome
       rx.error.get.code == 999
       rx.error.get.message == "fatal"
@@ -200,7 +200,7 @@ suite "jrpc_sys conversion":
       rx.jsonrpc.isSome
       rx.id.isSome
       rx.id.get.str == "gum"
-      rx.result.isNone
+      rx.result.string.len == 0
       rx.error.isSome
       rx.error.get.code == 999
       rx.error.get.message == "fatal"