JSONCodec support single value

runtimes/huggingface/mlserver_huggingface/codecs.py

@@ -196,6 +196,10 @@ def encode_output(cls, name: str, payload: Any, **kwargs) -> ResponseOutput:
     @classmethod
     def decode_output(cls, response_output: ResponseOutput) -> Any:
         strs = StringCodec.decode_output(response_output)
+        if is_single_value(response_output):
+            if len(strs) == 0:
+                raise ValueError("can't decode empty data as a single value")
+            return json.loads(strs[0])
         return [json.loads(el) for el in strs]
 
     @classmethod
@@ -208,8 +212,12 @@ def encode_input(cls, name: str, payload: List[Dict[str, Any]]) -> RequestInput:
         return rinput
 
     @classmethod
-    def decode_input(cls, request_input: RequestInput) -> Dict[str, Any]:
+    def decode_input(cls, request_input: RequestInput) -> Any:
         strs = StringCodec.decode_input(request_input)
+        if is_single_value(request_input):
+            if len(strs) == 0:
+                raise ValueError("can't decode empty data as a single value")
+            return json.loads(strs[0])
         return [json.loads(el) for el in strs]