Merge pull request #1117 from stealthycoin/fix-encoding-type-error

Fix encoding type error

CHANGELOG.rst

@@ -10,6 +10,9 @@ Next Release (TBD)
 * Fix handling of more complex Accept headers for binary
   content types
   (`#1078 <https://github.com/aws/chalice/issues/1078>`__)
+* Raise TypeError when trying to serialize an unserializable
+  type
+  (`#1100 <https://github.com/aws/chalice/issues/1100>`__)
 
 
 1.8.0

chalice/app.py

@@ -47,12 +47,13 @@ def unquote_str(value, encoding='utf-8'):
     _ANY_STRING = (basestring, bytes)  # noqa pylint: disable=E0602
 
 
-def handle_decimals(obj):
+def handle_extra_types(obj):
     # Lambda will automatically serialize decimals so we need
     # to support that as well.
     if isinstance(obj, decimal.Decimal):
         return float(obj)
-    return obj
+    raise TypeError('Object of type %s is not JSON serializable'
+                    % obj.__class__.__name__)
 
 
 def error_response(message, error_code, http_status_code, headers=None):
@@ -364,7 +365,7 @@ def to_dict(self, binary_types=None):
         body = self.body
         if not isinstance(body, _ANY_STRING):
             body = json.dumps(body, separators=(',', ':'),
-                              default=handle_decimals)
+                              default=handle_extra_types)
         response = {
             'headers': self.headers,
             'statusCode': self.status_code,

tests/unit/test_app.py

@@ -14,7 +14,7 @@
 
 from chalice import app
 from chalice import NotFoundError
-from chalice.app import APIGateway, Request, Response, handle_decimals
+from chalice.app import APIGateway, Request, Response, handle_extra_types
 from chalice import __version__ as chalice_version
 from chalice.deploy.validate import ExperimentalFeatureError
 from chalice.deploy.validate import validate_feature_flags
@@ -152,6 +152,16 @@ def test_invalid_binary_response_body_throws_value_error(sample_app):
         response.to_dict(sample_app.api.binary_types)
 
 
+def test_invalid_JSON_response_body_throws_type_error(sample_app):
+    response = app.Response(
+        status_code=200,
+        body={'foo': object()},
+        headers={'Content-Type': 'application/json'}
+    )
+    with pytest.raises(TypeError):
+        response.to_dict()
+
+
 def test_can_encode_binary_body_as_base64(sample_app):
     response = app.Response(
         status_code=200,
@@ -1399,7 +1409,7 @@ def test_http_request_to_dict_is_json_serializable(http_request_kwargs):
     request_dict = request.to_dict()
     # We should always be able to dump the request dict
     # to JSON.
-    assert json.dumps(request_dict, default=handle_decimals)
+    assert json.dumps(request_dict, default=handle_extra_types)
 
 
 @given(body=st.text(), headers=STR_MAP,