python - Rest Api 后定义失败 | python | flask

Question

我对Python很陌生。我对 python 有基本的想法，而 Flask 对我来说是全新的。尝试使用flask通过python学习rest api。但是，我在发布数据时遇到了这个问题。以下是示例代码和错误。请帮我解决这个问题。提前致谢。我尝试谷歌搜索但没有得到任何解决方案。

运行时出错

127.0.0.1 - - [03/Jan/2020 15:58:54] "POST /api/User HTTP/1.1" 500 -
  Traceback (most recent call last):
    File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1997, in __call__
      return self.wsgi_app(environ, start_response)
    File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1985, in wsgi_app
      response = self.handle_exception(e)
    File "/usr/local/lib/python3.7/site-packages/flask_restful/__init__.py", line 273, in error_router
      return original_handler(e)
    File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1540, in handle_exception
      reraise(exc_type, exc_value, tb)
    File "/usr/local/lib/python3.7/site-packages/flask/_compat.py", line 32, in reraise
      raise value.with_traceback(tb)
    File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1982, in wsgi_app
      response = self.full_dispatch_request()
    File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1614, in full_dispatch_request
      rv = self.handle_user_exception(e)
    File "/usr/local/lib/python3.7/site-packages/flask_restful/__init__.py", line 273, in error_router
      return original_handler(e)
    File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1517, in handle_user_exception
      reraise(exc_type, exc_value, tb)
    File "/usr/local/lib/python3.7/site-packages/flask/_compat.py", line 32, in reraise
      raise value.with_traceback(tb)
    File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1612, in full_dispatch_request
      rv = self.dispatch_request()
    File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1598, in dispatch_request
      return self.view_functions[rule.endpoint](**req.view_args)
    File "/usr/local/lib/python3.7/site-packages/flask_restful/__init__.py", line 480, in wrapper
      resp = resource(*args, **kwargs)
    File "/usr/local/lib/python3.7/site-packages/flask/views.py", line 84, in view
      return self.dispatch_request(*args, **kwargs)
    File "/usr/local/lib/python3.7/site-packages/flask_restful/__init__.py", line 595, in dispatch_request
      resp = meth(*args, **kwargs)
    File "/Users/z0034ff/Documents/music/resources/Users.py", line 32, in post
      typeid=json_data['typeid'],
  TypeError: __init__() got an unexpected keyword argument 'fname'

文件名:Model.py

from flask import Flask
  from marshmallow import Schema, fields, pre_load, validate
  from flask_marshmallow import Marshmallow
  from flask_sqlalchemy import SQLAlchemy


  ma = Marshmallow()
  db = SQLAlchemy()


  class Users(db.Model):
      __tablename__ = 'users'
      id = db.Column(db.Integer, primary_key=True)
      fname = db.Column(db.String(50), nullable=False)
      lname = db.Column(db.String(50), nullable=False)
      email = db.Column(db.String(100), nullable=False)
      phone = db.Column(db.String(50), nullable=False)
      typeid = db.Column(db.Integer, db.ForeignKey(
          'user_type.id', ondelete='CASCADE'), nullable=False)
      creation_date = db.Column(
          db.TIMESTAMP, server_default=db.func.current_timestamp(), nullable=False)

      def __init__(self, users, typeid):
          self.users = users
          self.typeid = typeid

  class UsersSchema(ma.Schema):
      id = fields.Integer(dump_only=True)
      fname = fields.String(required=True, validate=validate.Length(1))
      lname = fields.String(required=True, validate=validate.Length(1))
      email = fields.String(required=True, validate=validate.Length(1))
      phone = fields.String(required=True, validate=validate.Length(10))
      typeid = fields.Integer(required=True)
      creation_date = fields.DateTime()

文件名:Users.py

from flask import jsonify, request
  from flask_restful import Resource
  from Model import db, Users, UsersSchema

  users_schema = UsersSchema(many=True)
  user_schema = UsersSchema()


  class UsersResource(Resource):
      def get(self):
          users = Users.query.all()
          users = users_schema.dump(users).data
          return {"status": "success", "data": users}, 200

      def post(self):
          json_data = request.get_json(force=True)
          if not json_data:
              return {'message': 'No input data provided'}, 400
          # Validate and deserialize input
          data, errors = user_schema.load(json_data)
          if errors:
              return errors, 422
          user = Users.query.filter_by(email=data['email']).first()
          if user:
              return {'message': 'User already exists'}, 400
          print(json_data['fname'])
          user = Users(
              fname=json_data['fname'],
              lname=json_data['lname'],
              email=json_data['email'],
              phone=json_data['phone'],
              typeid=json_data['typeid'],
          )

          db.session.add(user)
          db.session.commit()

          result = user_schema.dump(user).data

          return {"status": 'success', 'data': result}, 201

Answer 1

没有必要定义SQLAlchemy模型构造函数。 SQLAlchemy docs解释:

Our User class, as defined using the Declarative system, has been provided with a constructor (e.g. init() method) which automatically accepts keyword names that match the columns we’ve mapped. We are free to define any explicit init() method we prefer on our class, which will override the default method provided by Declarative.

在Users.py第27行中，您尝试创建Users对象

          Users(
              fname=json_data['fname'],
              lname=json_data['lname'],
              email=json_data['email'],
              phone=json_data['phone'],
              typeid=json_data['typeid'],
          )

在 Model.py 中，Users 类的构造函数仅需要 2 个参数。

  class Users(db.Model):
    ....

      def __init__(self, users, typeid):
          ...

这就是错误的来源:类型错误:__init__() 获得意外的关键字参数“fname”

删除__init__后它应该可以正常工作。