Default response.encoding to utf-8 if response body is None

HISTORY.md

@@ -1,5 +1,8 @@
 # History
 
+## 0.4.2 (2021-07-26)
+* Fix handling of `CachedResponse.encoding` when the response body is `None`
+
 ## 0.4.1 (2021-07-09)
 * Fix initialziation of `SQLiteBackend` so it can be created outside main event loop
 

aiohttp_client_cache/response.py

@@ -52,7 +52,7 @@ class CachedResponse:
     status: int = attr.ib()
     url: URL = attr.ib(converter=URL)
     version: str = attr.ib()
-    _body: Any = attr.ib(default=None)
+    _body: Any = attr.ib(default=b'')
     _links: LinkItems = attr.ib(factory=list)
     cookies: SimpleCookie = attr.ib(default=None)
     created_at: datetime = attr.ib(factory=datetime.utcnow)
@@ -80,11 +80,12 @@ async def from_client_response(cls, client_response: ClientResponse, expires: da
         response.expires = expires
         response.real_url = client_response.request_info.real_url
 
-        # The encoding may be unset even if the response has been read
+        # The encoding may be unset even if the response has been read, and
+        # get_encoding() does not handle certain edge cases like an empty response body
         try:
             response.encoding = client_response.get_encoding()
-        except RuntimeError:
-            pass
+        except (RuntimeError, TypeError):
+            response.encoding = 'utf-8'
 
         if client_response.history:
             response.history = (

test/unit/test_response.py

@@ -14,6 +14,7 @@ async def get_test_response(client_factory, url='/', **kwargs):
     app.router.add_route('GET', '/valid_url', mock_handler)
     app.router.add_route('GET', '/json', json_mock_handler)
     app.router.add_route('GET', '/empty_content', empty_mock_handler)
+    app.router.add_route('GET', '/null_content', null_mock_handler)
     client = await client_factory(app)
     client_response = await client.get(url)
 
@@ -34,10 +35,15 @@ async def json_mock_handler(request):
     return web.Response(body=b'{"key": "value"}')
 
 
+# Note: Empty string vs null can trigger different corner cases
 async def empty_mock_handler(request):
     return web.Response(body=b' ')
 
 
+async def null_mock_handler(request):
+    return web.Response(body=None)
+
+
 async def test_basic_attrs(aiohttp_client):
     response = await get_test_response(aiohttp_client)
 
@@ -130,6 +136,11 @@ async def test_json__empty_content(aiohttp_client):
     assert await response.json() is None
 
 
+async def test_json__null_content(aiohttp_client):
+    response = await get_test_response(aiohttp_client, '/null_content')
+    assert await response.json() is None
+
+
 async def test_json__non_json_content(aiohttp_client):
     response = await get_test_response(aiohttp_client)
     with pytest.raises(ValueError):