json - 'User' 类型的对象不是 JSON 可序列化的(父类)

Question

我正在尝试通过 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(一个用户可以有多个项目)。我在插入新用户时没有问题，但是当我尝试在数据库中插入新项目时，它确实有效，但项目中的用户属性无法转换为 JSON。这是我的代码:

用户模型文件:

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:

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)

我添加项目的路由代码:

@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:

  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) + '\n',
  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

我希望返回一个 Project JSON，因此我可以转换为移动应用程序中存在的 Project 类。

Answer 1

您应该有一个返回 Projeto 对象的函数。 class 字典格式，然后转换成 jsonify它。就像是

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)

如果您需要为模型以 JSON 格式返回数据，则需要以 JSON 格式返回数据。目前使用这行代码，

return mProjeto.projeto_schema.jsonify(new_projeto)

您正在做的是尝试将 Usuario 和 Projeto 对象转换为 JSON 对象，这不是有效的数据类型 jsonify功能支持。这就是消息所指示的

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

对于 Usuario 类也可以这样做。