Preserve blank form values for urlencoded forms (option) (#2439)

* task(request.form): Add tests for blank values

* fix(request): abstract form property to implement get_form(), allow for preserving of blanks

* fix(request): hinting for parsed_form

* fix(request): typing for parsed_files

* fix(request): ignore type assumption

* fix(request): mypy typechecking caused E501 when type set to ignore

* fix(request): mypy is too stupid to parse continuations

* fix(request): formatting

* fix(request): fix annotation and return for get_form()

* fix(request): linting, hinting

sanic/request.py

@@ -152,8 +152,8 @@ class Request:
         self.parsed_accept: Optional[AcceptContainer] = None
         self.parsed_credentials: Optional[Credentials] = None
         self.parsed_json = None
-        self.parsed_form = None
-        self.parsed_files = None
+        self.parsed_form: Optional[RequestParameters] = None
+        self.parsed_files: Optional[RequestParameters] = None
         self.parsed_token: Optional[str] = None
         self.parsed_args: DefaultDict[
             Tuple[bool, bool, str, str], RequestParameters
@@ -426,9 +426,9 @@ class Request:
                 pass
         return self.parsed_credentials
 
-    @property
-    def form(self):
-        if self.parsed_form is None:
+    def get_form(
+        self, keep_blank_values: bool = False
+    ) -> Optional[RequestParameters]:
         self.parsed_form = RequestParameters()
         self.parsed_files = RequestParameters()
         content_type = self.headers.getone(
@@ -438,11 +438,16 @@ class Request:
         try:
             if content_type == "application/x-www-form-urlencoded":
                 self.parsed_form = RequestParameters(
-                        parse_qs(self.body.decode("utf-8"))
+                    parse_qs(
+                        self.body.decode("utf-8"),
+                        keep_blank_values=keep_blank_values,
+                    )
                 )
             elif content_type == "multipart/form-data":
                 # TODO: Stream this instead of reading to/from memory
-                    boundary = parameters["boundary"].encode("utf-8")
+                boundary = parameters["boundary"].encode(  # type: ignore
+                    "utf-8"
+                )  # type: ignore
                 self.parsed_form, self.parsed_files = parse_multipart_form(
                     self.body, boundary
                 )
@@ -451,6 +456,13 @@ class Request:
 
         return self.parsed_form
 
+    @property
+    def form(self):
+        if self.parsed_form is None:
+            self.get_form()
+
+        return self.parsed_form
+
     @property
     def files(self):
         if self.parsed_files is None:

tests/test_requests.py

@@ -1016,6 +1016,72 @@ async def test_post_form_urlencoded_asgi(app):
     assert request.form.get("test") == "OK"  # For request.parsed_form
 
 
+def test_post_form_urlencoded_keep_blanks(app):
+    @app.route("/", methods=["POST"])
+    async def handler(request):
+        request.get_form(keep_blank_values=True)
+        return text("OK")
+
+    payload = "test="
+    headers = {"content-type": "application/x-www-form-urlencoded"}
+
+    request, response = app.test_client.post(
+        "/", data=payload, headers=headers
+    )
+
+    assert request.form.get("test") == ""
+    assert request.form.get("test") == ""  # For request.parsed_form
+
+
+@pytest.mark.asyncio
+async def test_post_form_urlencoded_keep_blanks_asgi(app):
+    @app.route("/", methods=["POST"])
+    async def handler(request):
+        request.get_form(keep_blank_values=True)
+        return text("OK")
+
+    payload = "test="
+    headers = {"content-type": "application/x-www-form-urlencoded"}
+
+    request, response = await app.asgi_client.post(
+        "/", data=payload, headers=headers
+    )
+
+    assert request.form.get("test") == ""
+    assert request.form.get("test") == ""  # For request.parsed_form
+
+
+
+def test_post_form_urlencoded_drop_blanks(app):
+    @app.route("/", methods=["POST"])
+    async def handler(request):
+        return text("OK")
+
+    payload = "test="
+    headers = {"content-type": "application/x-www-form-urlencoded"}
+
+    request, response = app.test_client.post(
+        "/", data=payload, headers=headers
+    )
+
+    assert "test" not in request.form.keys()
+
+@pytest.mark.asyncio
+async def test_post_form_urlencoded_drop_blanks_asgi(app):
+    @app.route("/", methods=["POST"])
+    async def handler(request):
+        return text("OK")
+
+    payload = "test="
+    headers = {"content-type": "application/x-www-form-urlencoded"}
+
+    request, response = await app.asgi_client.post(
+        "/", data=payload, headers=headers
+    )
+
+    assert "test" not in request.form.keys()
+
+
 @pytest.mark.parametrize(
     "payload",
     [