#6 Empty display filter raises Parser Exception

pydictdisplayfilter/display_filters.py

@@ -91,9 +91,12 @@ def _evaluate_expressions(self, expressions, item) -> bool:
             raise EvaluationError(err)
 
     def _filter_data(self, data: List, expressions: List[Union[Expression, str]]) -> List:
-        for item in data:
-            if self._evaluate_expressions(expressions, item):
-                yield item
+        if expressions:
+            for item in data:
+                if self._evaluate_expressions(expressions, item):
+                    yield item
+        else:
+            yield from data
 
     @property
     def field_names(self) -> List[str]:

pydictdisplayfilter/parsers/display_filter.py

@@ -137,6 +137,8 @@ def parse(self, format: str) -> List[Union[Expression, str]]:
         :raises ParserError, when the given display filter could not be parsed correctly.
         """
         try:
+            if not format or not format.strip():
+                return []
             return self._display_filter_format.parseString(format, parseAll=True).asList()
         except Exception:
             # This error indicates that there is something wrong with the given display filter.

setup.py

@@ -11,7 +11,7 @@
 # This call to setup() does all the work
 setup(
     name="python-dict-display-filter",
-    version="1.0.0",
+    version="1.1.0",
     description="A Wireshark-like display filter for dictionaries.",
     long_description=README,
     long_description_content_type="text/markdown",

tests/test_dict_display_filter.py

@@ -89,6 +89,15 @@ class TestDictDisplayFilter(unittest.TestCase):
         {"value": "False"},
     ]
 
+    @parameterized.expand([
+        [None],
+        [''],
+        [' ']
+    ])
+    def test_empty_display_filter_return_all_items(self, display_filter):
+        actual_result = list(DictDisplayFilter(self.data).filter(display_filter))
+        self.assertEqual(len(actual_result), len(self.data))
+
     @parameterized.expand([
         # Field existence
         ['name', 4],

tests/test_display_filter_parser.py

@@ -26,6 +26,14 @@ class TestFilterStringParser(TestCase):
     display_filter_parser = DisplayFilterParser(['address', 'port', 'protocol', 'banner'])
     generic_display_filter_parser = DisplayFilterParser()
 
+    @parameterized.expand([
+        [None],
+        [''],
+        [' ']
+    ])
+    def test_empty_query_returns_empty_list(self, display_filter):
+        self.assertEqual(self.display_filter_parser.parse(display_filter), [])
+
     @parameterized.expand([
         ['127.0.0.1'],
         ['127.0.0.1/24'],

tests/test_sql_display_filter.py

@@ -82,6 +82,14 @@ def _build_insert_table_data_command():
             data = tuple(table_data_row.values())
             connection.execute(insert_table_data_command, data)
 
+    @parameterized.expand([
+        [None],
+        [''],
+        [' ']
+    ])
+    def test_empty_display_filter_returns_all_items(self, display_filter):
+        self.assertEqual(len(list(SQLDisplayFilter(self._connection, 'data').filter(display_filter))), len(self.data))
+
     @parameterized.expand([
         # Field existence
         ['name', 4],