Handle decoding errors like json decode errors (#428)

* Handle decoding errors like json decode errors

When receiving a post containing non utf8 data with a Application/Json
content-type, the decoding fails.  This should be treated as an
incorrect JSON payload and return a 400.

fixes #427

* Update changelog and AUTHORS

AUTHORS.rst

@@ -40,3 +40,4 @@ Contributors (chronological)
 * Xiaoyu Lee <https://github.com/lee3164>
 * Jonathan Angelo <https://github.com/jangelo>
 * @zhenhua32 <https://github.com/zhenhua32>
+* Martin Roy <https://github.com/lindycoder>

CHANGELOG.rst

@@ -1,6 +1,14 @@
 Changelog
 ---------
 
+5.5.2 (unreleased)
+******************
+
+Bug fixes:
+
+* Handle ``UnicodeDecodeError`` when parsing JSON payloads (:issue:`427`).
+  Thanks :user:`lindycoder` for the catch and patch.
+
 5.5.1 (2019-09-15)
 ******************
 

src/webargs/aiohttpparser.py

@@ -102,6 +102,9 @@ async def parse_json(self, req: Request, name: str, field: Field) -> typing.Any:
                     return core.missing
                 else:
                     return self.handle_invalid_json_error(e, req)
+            except UnicodeDecodeError as e:
+                return self.handle_invalid_json_error(e, req)
+
             self._cache["json"] = json_data
         return core.get_value(json_data, name, field, allow_many_nested=True)
 
@@ -164,7 +167,11 @@ def handle_error(
         )
 
     def handle_invalid_json_error(
-        self, error: json.JSONDecodeError, req: Request, *args, **kwargs
+        self,
+        error: typing.Union[json.JSONDecodeError, UnicodeDecodeError],
+        req: Request,
+        *args,
+        **kwargs
     ) -> "typing.NoReturn":
         error_class = exception_map[400]
         messages = {"json": ["Invalid JSON body."]}

src/webargs/bottleparser.py

@@ -47,6 +47,9 @@ def parse_json(self, req, name, field):
                     return core.missing
                 else:
                     return self.handle_invalid_json_error(e, req)
+            except UnicodeDecodeError as e:
+                return self.handle_invalid_json_error(e, req)
+
             if json_data is None:
                 return core.missing
         return core.get_value(json_data, name, field, allow_many_nested=True)

src/webargs/core.py

@@ -112,7 +112,14 @@ def get_value(data, name, field, allow_many_nested=False):
 
 def parse_json(s, encoding="utf-8"):
     if isinstance(s, bytes):
-        s = s.decode(encoding)
+        try:
+            s = s.decode(encoding)
+        except UnicodeDecodeError as e:
+            raise json.JSONDecodeError(
+                "Bytes decoding error : {}".format(e.reason),
+                doc=str(e.object),
+                pos=e.start,
+            )
     return json.loads(s)
 
 

src/webargs/testing.py

@@ -117,6 +117,18 @@ def test_parse_json_with_nonascii_chars(self, testapp):
         text = u"øˆƒ£ºº∆ƒˆ∆"
         assert testapp.post_json("/echo", {"name": text}).json == {"name": text}
 
+    # https://github.com/marshmallow-code/webargs/issues/427
+    def test_parse_json_with_nonutf8_chars(self, testapp):
+        res = testapp.post(
+            "/echo",
+            b"\xfe",
+            headers={"Accept": "application/json", "Content-Type": "application/json"},
+            expect_errors=True,
+        )
+
+        assert res.status_code == 400
+        assert res.json == {"json": ["Invalid JSON body."]}
+
     def test_validation_error_returns_422_response(self, testapp):
         res = testapp.post("/echo", {"name": "b"}, expect_errors=True)
         assert res.status_code == 422

tests/test_falconparser.py

@@ -16,6 +16,18 @@ def test_parse_files(self, testapp):
     def test_use_args_hook(self, testapp):
         assert testapp.get("/echo_use_args_hook?name=Fred").json == {"name": "Fred"}
 
+    # https://github.com/marshmallow-code/webargs/issues/427
+    def test_parse_json_with_nonutf8_chars(self, testapp):
+        res = testapp.post(
+            "/echo",
+            b"\xfe",
+            headers={"Accept": "application/json", "Content-Type": "application/json"},
+            expect_errors=True,
+        )
+
+        assert res.status_code == 400
+        assert res.json["errors"] == {"json": ["Invalid JSON body."]}
+
     # https://github.com/sloria/webargs/issues/329
     def test_invalid_json(self, testapp):
         res = testapp.post(