Question

鉴于以下模型：

class BaseModel(Model):
    class Meta:
        database = database

class ContentItem(BaseModel):
    content = JSONField(index=True)
    content_item_set = TextField(db_column='content_item_set_id')
    id = TextField(primary_key=True)
    original_content = TextField(null=True)
    timestamp = DateTimeField()

    class Meta:
        db_table = 'content_item'
        schema = 'cola'

当我尝试在Chalice视图中显示时，我有循环引用。

@app.route("/")
def list_items():
    return [model_to_dict(i) for i in ContentItem.select().limit(10)]

错误：

Traceback (most recent call last):
  File "/usr/local/Cellar/python3/3.6.2/Frameworks/Python.framework/Versions/3.6/lib/python3.6/socketserver.py", line 317, in _handle_request_noblock
    self.process_request(request, client_address)
  File "/usr/local/Cellar/python3/3.6.2/Frameworks/Python.framework/Versions/3.6/lib/python3.6/socketserver.py", line 348, in process_request
    self.finish_request(request, client_address)
  File "/usr/local/Cellar/python3/3.6.2/Frameworks/Python.framework/Versions/3.6/lib/python3.6/socketserver.py", line 361, in finish_request
    self.RequestHandlerClass(request, client_address, self)
  File "/Users/jameslin/virtualenvs/cola-management-services/lib/python3.6/site-packages/chalice/local.py", line 514, in __init__
    self, request, client_address, server)  # type: ignore
  File "/usr/local/Cellar/python3/3.6.2/Frameworks/Python.framework/Versions/3.6/lib/python3.6/socketserver.py", line 696, in __init__
    self.handle()
  File "/usr/local/Cellar/python3/3.6.2/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/server.py", line 418, in handle
    self.handle_one_request()
  File "/usr/local/Cellar/python3/3.6.2/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/server.py", line 406, in handle_one_request
    method()
  File "/Users/jameslin/virtualenvs/cola-management-services/lib/python3.6/site-packages/chalice/local.py", line 535, in _generic_handle
    body=body
  File "/Users/jameslin/virtualenvs/cola-management-services/lib/python3.6/site-packages/chalice/local.py", line 468, in handle_request
    response = self._app_object(lambda_event, lambda_context)
  File "/Users/jameslin/virtualenvs/cola-management-services/lib/python3.6/site-packages/chalice/app.py", line 627, in __call__
    response = response.to_dict(self.api.binary_types)
  File "/Users/jameslin/virtualenvs/cola-management-services/lib/python3.6/site-packages/chalice/app.py", line 317, in to_dict
    body = json.dumps(body, default=handle_decimals)
  File "/usr/local/Cellar/python3/3.6.2/Frameworks/Python.framework/Versions/3.6/lib/python3.6/json/__init__.py", line 238, in dumps
    **kw).encode(obj)
  File "/usr/local/Cellar/python3/3.6.2/Frameworks/Python.framework/Versions/3.6/lib/python3.6/json/encoder.py", line 199, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/usr/local/Cellar/python3/3.6.2/Frameworks/Python.framework/Versions/3.6/lib/python3.6/json/encoder.py", line 257, in iterencode
    return _iterencode(o, 0)
ValueError: Circular reference detected

Answer 1

可能是DateTimeField。 Chalice JSON编码器不处理DateTimeField（显然仅处理decimal）：https://github.com/aws/chalice/blob/master/chalice/app.py#L351

针对此类似问题的建议解决方法是在序列化之前先处理数据，然后将datetime更改为另一种类型（可能是字符串表示形式）：https://github.com/aws/chalice/issues/288#issuecomment-302896045 < / p>

在圣杯视图中检测到Peewee循环参考

1 个答案: