json: raise ValueError invalid list or dict

If the expected datatype is ArrayType or DictType
but the json value is something else raise
ValueError instead of 500 erro because we can browse the
dict or the list.

Closes bug: #1428628

Change-Id: Ibd4d95815c0b81ded8304bba4ca83e6df32d86ae

wsme/rest/json.py

@@ -156,6 +156,8 @@ def fromjson(datatype, value):
 def array_fromjson(datatype, value):
     if value is None:
         return None
+    if not isinstance(value, list):
+        raise ValueError("Value not a valid list: %s" % value)
     return [fromjson(datatype.item_type, item) for item in value]
 
 
@@ -163,6 +165,8 @@ def array_fromjson(datatype, value):
 def dict_fromjson(datatype, value):
     if value is None:
         return None
+    if not isinstance(value, dict):
+        raise ValueError("Value not a valid dict: %s" % value)
     return dict((
         (fromjson(datatype.key_type, item[0]),
             fromjson(datatype.value_type, item[1]))

wsme/tests/test_restjson.py

@@ -11,7 +11,8 @@ except:
 
 from wsme.rest.json import fromjson, tojson, parse
 from wsme.utils import parse_isodatetime, parse_isotime, parse_isodate
-from wsme.types import isarray, isdict, isusertype, register_type, UserType
+from wsme.types import isarray, isdict, isusertype, register_type
+from wsme.types import UserType, ArrayType, DictType
 from wsme.rest import expose, validate
 from wsme.exc import ClientSideError, InvalidInput
 
@@ -325,6 +326,28 @@ class TestRestJson(wsme.tests.protocol.RestOnlyProtocolTestCase):
         j = parse('{"a": "2011-01-01"}', {'a': datetime.date}, False)
         assert isinstance(j['a'], datetime.date)
 
+    def test_invalid_list_fromjson(self):
+        jlist = "invalid"
+        try:
+            parse('{"a": "%s"}' % jlist, {'a': ArrayType(str)}, False)
+            assert False
+        except Exception as e:
+            assert isinstance(e, InvalidInput)
+            assert e.fieldname == 'a'
+            assert e.value == jlist
+            assert e.msg == "Value not a valid list: %s" % jlist
+
+    def test_invalid_dict_fromjson(self):
+        jdict = "invalid"
+        try:
+            parse('{"a": "%s"}' % jdict, {'a': DictType(str, str)}, False)
+            assert False
+        except Exception as e:
+            assert isinstance(e, InvalidInput)
+            assert e.fieldname == 'a'
+            assert e.value == jdict
+            assert e.msg == "Value not a valid dict: %s" % jdict
+
     def test_invalid_date_fromjson(self):
         jdate = "2015-01-invalid"
         try: