Preserve empty query strings and fragments

rfc3986/normalizers.py

@@ -43,10 +43,14 @@ def normalize_path(path):
 
 
 def normalize_query(query):
+    if not query:
+        return query
     return normalize_percent_characters(query)
 
 
 def normalize_fragment(fragment):
+    if not fragment:
+        return fragment
     return normalize_percent_characters(fragment)
 
 

rfc3986/parseresult.py

@@ -76,8 +76,8 @@ class ParseResult(namedtuple('ParseResult', PARSED_COMPONENTS),
             host,
             port or None,
             path or None,
-            query or None,
-            fragment or None)
+            query,
+            fragment)
         parse_result.encoding = encoding
         parse_result.reference = uri_ref
         return parse_result

rfc3986/uri.py

@@ -38,8 +38,8 @@ class URIReference(namedtuple('URIReference', URI_COMPONENTS)):
             scheme or None,
             authority or None,
             path or None,
-            query or None,
-            fragment or None)
+            query,
+            fragment)
         ref.encoding = encoding
         return ref
 
@@ -264,8 +264,8 @@ class URIReference(namedtuple('URIReference', URI_COMPONENTS)):
                             normalize_authority(
                                 (self.userinfo, self.host, self.port)),
                             normalize_path(self.path or ''),
-                            normalize_query(self.query or ''),
-                            normalize_fragment(self.fragment or ''))
+                            normalize_query(self.query),
+                            normalize_fragment(self.fragment))
 
     def normalized_equality(self, other_ref):
         """Compare this URIReference to another URIReference.
@@ -358,9 +358,9 @@ class URIReference(namedtuple('URIReference', URI_COMPONENTS)):
             result_list.extend(['//', self.authority])
         if self.path:
             result_list.append(self.path)
-        if self.query:
+        if self.query is not None:
             result_list.extend(['?', self.query])
-        if self.fragment:
+        if self.fragment is not None:
             result_list.extend(['#', self.fragment])
         return ''.join(result_list)
 

tests/test_normalizers.py

@@ -70,3 +70,9 @@ def test_authority_normalization():
     uri = URIReference(
         None, 'user%2aName@EXAMPLE.COM', None, None, None).normalize()
     assert uri.authority == 'user%2AName@example.com'
+
+
+def test_fragment_normalization():
+    uri = URIReference(
+        None, 'example.com', None, None, 'fiz%DF').normalize()
+    assert uri.fragment == 'fiz%DF'

tests/test_uri.py

@@ -337,3 +337,10 @@ class TestURIReferencesResolve:
         T = R.resolve_with(B)
         assert T.path is None
         assert T.query == 'query'
+
+
+def test_empty_querystrings_persist():
+    url = 'https://httpbin.org/get?'
+    ref = URIReference.from_string(url)
+    assert ref.query == ''
+    assert ref.unsplit() == url