关于flask：“User”类型的对象不是JSON可序列化的(父类)


Object of type 'User' is not JSON serializable (Parent class)

我正试图通过我的Flask API在我的数据库中插入一条记录。 User和Project类之间的关系是一对多(用户可以有很多项目)。 我在插入新用户时没有任何问题，但是当我尝试在数据库中插入一个新项目时，它实际上是可行的，但项目中的用户属性不能转换为JSON。 这是我的代码：

用户模型文件：

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class Usuario(db.Model):
 id = db.Column(db.BigInteger, primary_key=True)
 login = db.Column(db.String(80), unique=True, nullable=False)
 email = db.Column(db.String(120), unique=True, nullable=False)
 nome = db.Column(db.String(80), nullable=False)
 senha = db.Column(db.String(80), nullable=False)
 telefone = db.Column(db.String(80))
 receivedNotification = db.Column(
    db.Boolean, default=False, nullable=False)
 receivedEmail = db.Column(db.Boolean, default=False, nullable=False)
 emailVerificated = db.Column(db.Boolean, default=False, nullable=False)
 imagem = db.Column(db.LargeBinary(length=(2 ** 32) - 1))

 def __init__(self, login='', email='', nome='', senha='',
             telefone='', received_notification=False,
             received_email=False, email_verificated=False, imagem=None, init_dict=None):
    if init_dict is None:
        self.login = login
        self.email = email
        self.nome = nome
        self.senha = senha
        self.telefone = telefone
        self.receivedNotification = received_notification
        self.receivedEmail = received_email
        self.emailVerificated = email_verificated
        self.imagem = imagem
    else:
        for key in init_dict:
            setattr(self, key, init_dict[key])
class UsuarioSchema(ma.Schema):
class Meta:
    fields = ('id', 'login', 'email', 'nome', 'telefone',
              'receivedNotification', 'receivedEmail', 'emailVerificated', 'imagem')

user_schema = UsuarioSchema()
users_schema = UsuarioSchema(many=True)

项目模型文件：

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class Projeto(db.Model):
  codigo = db.Column(db.BigInteger, primary_key=True)
  nome = db.Column(db.String(100))
  descricao = db.Column(db.String(200))
  dataCriacao = db.Column(db.Date)
  dataPrevFinalizacao = db.Column(db.Date)
  dataFinalizacao = db.Column(db.Date)
  usuarioAdmId = db.Column(db.BigInteger,
                         db.ForeignKey('usuario.id'), nullable=False)
  usuarioAdm = db.relationship('Usuario',
                             backref=db.backref('projetos', lazy=True))

  def __init__(self, nome, descricao, data_criacao,
             data_prev_finalizacao, usuario_adm_id, data_finalizacao=None):
    self.nome = nome
    self.descricao = descricao
    self.dataCriacao = data_criacao
    self.dataPrevFinalizacao = data_prev_finalizacao
    self.dataFinalizacao = data_finalizacao
    self.usuarioAdmId = usuario_adm_id

class ProjetoSchema(ma.Schema):
class Meta:
    fields = ('nome', 'descricao', 'dataCriacao',
              'dataPrevFinalizacao', 'dataFinalizacao', 'usuarioAdm')

projeto_schema = ProjetoSchema()
projetos_schema = ProjetoSchema(many=True)

我添加项目的路线代码：

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@projeto_controller.route(mapping, methods=['POST'])
def add_projeto():
  nome = request.json['nome']
  descricao = request.json['descricao']
  data_criacao = request.json['dataCriacao']
  data_criacao = datetime.strptime(
    data_criacao, '%b %d, %Y %I:%M:%S %p').date()
  data_prev_finalizacao = request.json['dataPrevFinalizacao']
  data_prev_finalizacao = datetime.strptime(
    data_prev_finalizacao, '%b %d, %Y %I:%M:%S %p').date()
  usuario_adm_id = request.json['usuarioAdm']['id']
  usuario_adm = request.json['usuarioAdm']

  usuario = mUsuario.Usuario.query.get(usuario_adm_id)
  usuarioAdm = usuario

  new_projeto = mProjeto.Projeto(nome=nome, descricao=descricao,
                               data_criacao=data_criacao,

  data_prev_finalizacao=data_prev_finalizacao,
                               usuario_adm_id=usuario_adm_id)

  new_projeto.usuarioAdm = usuarioAdm
  usuarioAdm.projetos.append(new_projeto)

  db.session.commit()
  return mProjeto.projeto_schema.jsonify(new_projeto)

错误信息：

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  File"/anaconda3/envs/KeepSoft/lib/python3.7/site-packages/flask/app.py", line 2309, in __call__
return self.wsgi_app(environ, start_response)
 File"/anaconda3/envs/KeepSoft/lib/python3.7/site-packages/flask/app.py", line 2295, in wsgi_app
response = self.handle_exception(e)
  File"/anaconda3/envs/KeepSoft/lib/python3.7/site-packages/flask/app.py", line 1741, in handle_exception
reraise(exc_type, exc_value, tb)
  File"/anaconda3/envs/KeepSoft/lib/python3.7/site-packages/flask/_compat.py", line 35, in reraise
raise value
  File"/anaconda3/envs/KeepSoft/lib/python3.7/site-packages/flask/app.py", line 2292, in wsgi_app
response = self.full_dispatch_request()
  File"/anaconda3/envs/KeepSoft/lib/python3.7/site-packages/flask/app.py", line 1815, in full_dispatch_request
rv = self.handle_user_exception(e)
  File"/anaconda3/envs/KeepSoft/lib/python3.7/site-packages/flask/app.py", line 1718, in handle_user_exception
reraise(exc_type, exc_value, tb)
  File"/anaconda3/envs/KeepSoft/lib/python3.7/site-packages/flask/_compat.py", line 35, in reraise
raise value
  File"/anaconda3/envs/KeepSoft/lib/python3.7/site-packages/flask/app.py", line 1813, in full_dispatch_request
rv = self.dispatch_request()
  File"/anaconda3/envs/KeepSoft/lib/python3.7/site-packages/flask/app.py", line 1799, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
  File"/Users/user/Python/KeepSoftPythonAPI/controller/ProjetoController.py", line 93, in add_projeto
return mProjeto.projeto_schema.jsonify(new_projeto)
  File"/anaconda3/envs/KeepSoft/lib/python3.7/site-packages/flask_marshmallow/schema.py", line 42, in jsonify
return flask.jsonify(data, *args, **kwargs)
  File"/anaconda3/envs/KeepSoft/lib/python3.7/site-packages/flask/json/__init__.py", line 321, in jsonify
dumps(data, indent=indent, separators=separators) + '
',
  File"/anaconda3/envs/KeepSoft/lib/python3.7/site-packages/flask/json/__init__.py", line 179, in dumps
rv = _json.dumps(obj, **kwargs)
  File"/anaconda3/envs/KeepSoft/lib/python3.7/json/__init__.py", line 238, in dumps
**kw).encode(obj)
  File"/anaconda3/envs/KeepSoft/lib/python3.7/json/encoder.py", line 201, in encode
chunks = list(chunks)
  File"/anaconda3/envs/KeepSoft/lib/python3.7/json/encoder.py", line 431, in _iterencode
yield from _iterencode_dict(o, _current_indent_level)
  File"/anaconda3/envs/KeepSoft/lib/python3.7/json/encoder.py", line 405, in _iterencode_dict
yield from chunks
  File"/anaconda3/envs/KeepSoft/lib/python3.7/json/encoder.py", line 438, in _iterencode
o = _default(o)
  File"/anaconda3/envs/KeepSoft/lib/python3.7/site-packages/flask/json/__init__.py", line 81, in default
return _json.JSONEncoder.default(self, o)
  File"/anaconda3/envs/KeepSoft/lib/python3.7/json/encoder.py", line 179, in default
raise TypeError(f'Object of type {o.__class__.__name__} '
  TypeError: Object of type Usuario is not JSON serializable

我期望返回一个Project JSON，所以我可以转换为我的移动应用程序中存在的Project类。

相关讨论

你应该有一个函数以字典格式返回Projeto类的对象，然后将其转换为jsonify它。就像是

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def get_objects(self):
   """
    This function creates a dictionary and assigns
    the keys of the dictionary with the objects of
    the class and returns it in a json format.
   """
    data = {
        'nome': self.nome,
        'descricao': self.descricao,
        'data_criacao': self.dataCriacao,
        'data_prev_finalizacao': self.dataPrevFinalizacao,
        'data_finalizacao': self.dataFinalizacao,
        'usuario_adm_id': self.usuarioAdmId
    }
    return jsonify(data)

如果需要以模型的JSON格式返回数据，则需要以JSON格式返回数据。目前有这行代码，

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return mProjeto.projeto_schema.jsonify(new_projeto)

你正在做的是你试图将Usuario和Projeto对象转换为JSON对象，这不是jsonify函数支持的有效数据类型。这就是消息所表明的

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raise TypeError(f'Object of type {o.__class__.__name__} '
  TypeError: Object of type Usuario is not JSON serializable

Usuario类也可以这样做。

经过大量搜索，我能够解决我的问题。我必须明确定义ProjetoSchema类中定义的对象usuario是嵌套对象，因此只有在检索Projeto时，才能将此对象正确加载为JSON。

那么，现在这个修改后的Schema：

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class ProjetoSchema(ma.Schema):

  class Meta:
      fields = ('codigo', 'nome', 'descricao', 'dataCriacao',
              'dataPrevFinalizacao', 'dataFinalizacao', 'usuarioAdm')
      model = Projeto
  usuarioAdm = ma.Nested('UsuarioSchema', exclude=('projetos',))
  perfis = ma.Nested('PerfilSchema', many=True, exclude=('projeto',))


  projeto_schema = ProjetoSchema()
  projetos_schema = ProjetoSchema(many=True)

这是修改后的UsuarioSchema：

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class UsuarioSchema(ma.Schema):
  class Meta:
      fields = ('id', 'login', 'email', 'nome', 'telefone', 'receivedNotification',
              'receivedEmail', 'emailVerificated', 'imagem')
      model = Usuario
  projetos = ma.Nested('ProjetoSchema', many=True, exclude=('usuarioAdm',))
  perfis = ma.Nested('PerfilSchema', many=True, exclude=('usuario',))


  user_schema = UsuarioSchema()
  users_schema = UsuarioSchema(many=True)

这样，我不需要像我在获得最终代码之前那样处理无限的嵌套对象。毕竟这些行中的一些是不必要的，因为当我检索usuario时，我省略了包含它的Projeto子元素的字段，当重新执行Projeto时，它现在正确显示它的父元素。

原谅我的英语，我是巴西人。

感谢所有提示和解决方案。