allow a setter_fun in schema validator

allows to set values during validation

Author: lazedo

src/jesse_schema_validator.erl

@@ -40,10 +40,11 @@
               , Options    :: [{Key :: atom(), Data :: any()}]
               ) -> {ok, jesse:json_term()}
                  | no_return().
-validate(JsonSchema, Value, Options) ->
+validate(JsonSchema, Value, Options0) ->
+  Options = [{with_value, Value} | proplists:delete(with_value, Options0)],
   State    = jesse_state:new(JsonSchema, Options),
   NewState = validate_with_state(JsonSchema, Value, State),
-  {result(NewState), Value}.
+  {result(NewState), jesse_state:get_current_value(NewState)}.
 
 %% @doc Validates json `Data' against `JsonSchema' with `State'.
 %% If the given json is valid, then the latest state is returned to the caller,

src/jesse_state.erl

@@ -27,6 +27,7 @@
 -export([ add_to_path/2
         , get_allowed_errors/1
         , get_external_validator/1
+        , get_current_value/1
         , get_current_path/1
         , get_current_schema/1
         , get_current_schema_id/1
@@ -37,6 +38,7 @@
         , remove_last_from_path/1
         , set_allowed_errors/2
         , set_current_schema/2
+        , set_value/3
         , set_error_list/2
         , resolve_ref/2
         , undo_resolve_ref/2
@@ -63,10 +65,17 @@
          , default_schema_ver :: schema_ver()
          , schema_loader_fun  :: schema_loader_fun()
          , external_validator :: external_validator()
+         , setter_fun         :: setter_fun()
          , id                 :: schema_id()
          }
        ).
 
+-type setter_fun() :: fun(( jesse:json_path()
+                          , jesse:json_term()
+                          , jesse:json_term()
+                          ) -> jesse:json_term())
+                    | undefined.
+
 -opaque options() :: #options{}.
 -opaque state() :: #state{}.
 
@@ -145,6 +154,9 @@ new(JsonSchema, Options) ->
                                  , Options
                                  , ?default_schema_loader_fun
                                  ),
+  SetterFun = proplists:get_value( setter_fun
+                                 , Options
+                                 ),
   NewState = #state{ root_schema        = JsonSchema
                    , current_path       = []
                    , allowed_errors     = AllowedErrors
@@ -153,6 +165,7 @@ new(JsonSchema, Options) ->
                    , default_schema_ver = DefaultSchemaVer
                    , schema_loader_fun  = LoaderFun
                    , external_validator = ExternalValidator
+                   , setter_fun         = SetterFun
                    },
   set_current_schema(NewState, JsonSchema).
 
@@ -389,3 +402,15 @@ load_schema(#state{schema_loader_fun = LoaderFun}, SchemaURI) ->
 %% @private
 get_external_validator(#state{external_validator = Fun}) ->
   Fun.
+
+%% @doc Getter for `current_value'.
+-spec get_current_value(State :: state()) -> jesse:json_term().
+get_current_value(#state{current_value = Value}) -> Value.
+
+-spec set_value(State :: state(), jesse:path(), jesse:json_term()) -> state().
+set_value(#state{setter_fun=undefined}=State, _Path, _Value) -> State;
+set_value(#state{current_value=undefined}=State, _Path, _Value) -> State;
+set_value(#state{setter_fun=Setter
+                ,current_value=Value
+                }=State, Path, NewValue) ->
+    State#state{current_value = Setter(Path, NewValue, Value)}.