Rest API POST 定义失败 | Python | Flask

huangapple
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英文:

Rest Api post definition failing | Python | Flask

问题

I am very new to python. I have basic idea with python and flask is totally new for me. Trying to learn rest api with python using flask. But, I am facing the issue while posting data. below are sample code and error. Please help me to fix this issue. Thanks in advance. I tried googling but did not get any solution.

Error while running

  1. 127.0.0.1 - - [03/Jan/2020 15:58:54] "POST /api/User HTTP/1.1" 500 -
  2.   Traceback (most recent call last):
  3.     File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1997, in __call__
  4.       return self.wsgi_app(environ, start_response)
  5.     File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1985, in wsgi_app
  6.       response = self.handle_exception(e)
  7.     File "/usr/local/lib/python3.7/site-packages/flask_restful/__init__.py", line 273, in error_router
  8.       return original_handler(e)
  9.     File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1540, in handle_exception
  10.       reraise(exc_type, exc_value, tb)
  11.     File "/usr/local/lib/python3.7/site-packages/flask/_compat.py", line 32, in reraise
  12.       raise value.with_traceback(tb)
  13.     File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1982, in wsgi_app
  14.       response = self.full_dispatch_request()
  15.     File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1614, in full_dispatch_request
  16.       rv = self.handle_user_exception(e)
  17.     File "/usr/local/lib/python3.7/site-packages/flask_restful/__init__.py", line 273, in error_router
  18.       return original_handler(e)
  19.     File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1517, in handle_user_exception
  20.       reraise(exc_type, exc_value, tb)
  21.     File "/usr/local/lib/python3.7/site-packages/flask/_compat.py", line 32, in reraise
  22.       raise value.with_traceback(tb)
  23.     File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1612, in full_dispatch_request
  24.       rv = thispatch_request()
  25.     File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1598, in dispatch_request
  26.       return self.view_functions[rule.endpoint](**req.view_args)
  27.     File "/usr/local/lib/python3.7/site-packages/flask_restful/__init__.py", line 480, in wrapper
  28.       resp = resource(*args, **kwargs)
  29.     File "/usr/local/lib/python3.7/site-packages/flask/views.py", line 84, in view
  30.       return thispatch_request(*args, **kwargs)
  31.     File "/usr/local/lib/python3.7/site-packages/flask_restful/__init__.py", line 595, in dispatch_request
  32.       resp = meth(*args, **kwargs)
  33.     File "/Users/z0034ff/Documents/music/resources/Users.py", line 32, in post
  34.       typeid=json_data['typeid'],
  35.   TypeError: __init__() got an unexpected keyword argument 'fname'

File name: Model.py

  1. from flask import Flask
  2.   from marshmallow import Schema, fields, pre_load, validate
  3.   from flask_marshmallow import Marshmallow
  4.   from flask_sqlalchemy import SQLAlchemy
  7.   ma = Marshmallow()
  8.   db = SQLAlchemy()
  11.   class Users(db.Model):
  12.       __tablename__ = 'users'
  13.       id = db.Column(db.Integer, primary_key=True)
  14.       fname = db.Column(db.String(50), nullable=False)
  15.       lname = db.Column(db.String(50), nullable=False)
  16.       email = db.Column(db.String(100), nullable=False)
  17.       phone = db.Column(db.String(50), nullable=False)
  18.       typeid = db.Column(db.Integer, db.ForeignKey(
  19.           'user_type.id', ondelete='CASCADE'), nullable=False)
  20.       creation_date = db.Column(
  21.           db.TIMESTAMP, server_default=db.func.current_timestamp(), nullable=False)
  23.       def __init__(self, users, typeid):
  24.           self.users = users
  25.           self.typeid = typeid
  27.   class UsersSchema(ma.Schema):
  28.       id = fields.Integer(dump_only=True)
  29.       fname = fields.String(required=True, validate=validate.Length(1))
  30.       lname = fields.String(required=True, validate=validate.Length(1))
  31.       email = fields.String(required=True, validate=validate.Length(1))
  32.       phone = fields.String(required=True, validate=validate.Length(10))
  33.       typeid = fields.Integer(required=True)
  34.       creation_date = fields.DateTime()

File name: Users.py

  1. from flask import jsonify, request
  2.   from flask_restful import Resource
  3.   from Model import db, Users, UsersSchema
  5.   users_schema = UsersSchema(many=True)
  6.   user_schema = UsersSchema()
  9.   class UsersResource(Resource):
  10.       def get(self):
  11.           users = Users.query.all()
  12.           users = users_schema.dump(users).data
  13.           return {"status": "success", "data": users}, 200
  15.       def post(self):
  16.           json_data = request.get_json(force=True)
  17.           if not json_data:
  18.               return {'message': 'No input data provided'}, 400
  19.           # Validate and deserialize input
  20.           data, errors = user_schema.load(json_data)
  21.           if errors:
  22.               return errors, 422
  23.           user = Users.query.filter_by(email=data['email']).first()
  24.           if user:
  25.               return {'message': 'User already exists'}, 400
  26.           print(json_data['fname'])
  27.           user = Users(
  28.               fname=json_data['fname'],
  29.               lname=json_data['lname'],
  30.               email=json_data['email'],
  31.               phone=json_data['phone'],
  32.               typeid=json_data['typeid'],
  33.           )
  35.           db.session.add(user)
  36.           db.session.commit()
  38.           result = user_schema.dump(user).data
  40.           return {"status": 'success', 'data': result}, 201
英文:

I am very new to python. I have basic idea with python and flask is totally new for me. Trying to learn rest api with python using flask. But, I am facing the issue while posting data. below are sample code and error. Please help me to fix this issue. Thanks in advance. I tried googling but did not get any solution.

Error while running

  1. 127.0.0.1 - - [03/Jan/2020 15:58:54] "POST /api/User HTTP/1.1" 500 -
  2.   Traceback (most recent call last):
  3.     File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1997, in __call__
  4.       return self.wsgi_app(environ, start_response)
  5.     File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1985, in wsgi_app
  6.       response = self.handle_exception(e)
  7.     File "/usr/local/lib/python3.7/site-packages/flask_restful/__init__.py", line 273, in error_router
  8.       return original_handler(e)
  9.     File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1540, in handle_exception
  10.       reraise(exc_type, exc_value, tb)
  11.     File "/usr/local/lib/python3.7/site-packages/flask/_compat.py", line 32, in reraise
  12.       raise value.with_traceback(tb)
  13.     File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1982, in wsgi_app
  14.       response = self.full_dispatch_request()
  15.     File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1614, in full_dispatch_request
  16.       rv = self.handle_user_exception(e)
  17.     File "/usr/local/lib/python3.7/site-packages/flask_restful/__init__.py", line 273, in error_router
  18.       return original_handler(e)
  19.     File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1517, in handle_user_exception
  20.       reraise(exc_type, exc_value, tb)
  21.     File "/usr/local/lib/python3.7/site-packages/flask/_compat.py", line 32, in reraise
  22.       raise value.with_traceback(tb)
  23.     File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1612, in full_dispatch_request
  24.       rv = self.dispatch_request()
  25.     File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1598, in dispatch_request
  26.       return self.view_functions[rule.endpoint](**req.view_args)
  27.     File "/usr/local/lib/python3.7/site-packages/flask_restful/__init__.py", line 480, in wrapper
  28.       resp = resource(*args, **kwargs)
  29.     File "/usr/local/lib/python3.7/site-packages/flask/views.py", line 84, in view
  30.       return self.dispatch_request(*args, **kwargs)
  31.     File "/usr/local/lib/python3.7/site-packages/flask_restful/__init__.py", line 595, in dispatch_request
  32.       resp = meth(*args, **kwargs)
  33.     File "/Users/z0034ff/Documents/music/resources/Users.py", line 32, in post
  34.       typeid=json_data['typeid'],
  35.   TypeError: __init__() got an unexpected keyword argument 'fname'

File name: Model.py

  1. from flask import Flask
  2.   from marshmallow import Schema, fields, pre_load, validate
  3.   from flask_marshmallow import Marshmallow
  4.   from flask_sqlalchemy import SQLAlchemy
  7.   ma = Marshmallow()
  8.   db = SQLAlchemy()
  11.   class Users(db.Model):
  12.       __tablename__ = 'users'
  13.       id = db.Column(db.Integer, primary_key=True)
  14.       fname = db.Column(db.String(50), nullable=False)
  15.       lname = db.Column(db.String(50), nullable=False)
  16.       email = db.Column(db.String(100), nullable=False)
  17.       phone = db.Column(db.String(50), nullable=False)
  18.       typeid = db.Column(db.Integer, db.ForeignKey(
  19.           'user_type.id', ondelete='CASCADE'), nullable=False)
  20.       creation_date = db.Column(
  21.           db.TIMESTAMP, server_default=db.func.current_timestamp(), nullable=False)
  23.       def __init__(self, users, typeid):
  24.           self.users = users
  25.           self.typeid = typeid
  27.   class UsersSchema(ma.Schema):
  28.       id = fields.Integer(dump_only=True)
  29.       fname = fields.String(required=True, validate=validate.Length(1))
  30.       lname = fields.String(required=True, validate=validate.Length(1))
  31.       email = fields.String(required=True, validate=validate.Length(1))
  32.       phone = fields.String(required=True, validate=validate.Length(10))
  33.       typeid = fields.Integer(required=True)
  34.       creation_date = fields.DateTime()

File name: Users.py

  1. from flask import jsonify, request
  2.   from flask_restful import Resource
  3.   from Model import db, Users, UsersSchema
  5.   users_schema = UsersSchema(many=True)
  6.   user_schema = UsersSchema()
  9.   class UsersResource(Resource):
  10.       def get(self):
  11.           users = Users.query.all()
  12.           users = users_schema.dump(users).data
  13.           return {"status": "success", "data": users}, 200
  15.       def post(self):
  16.           json_data = request.get_json(force=True)
  17.           if not json_data:
  18.               return {'message': 'No input data provided'}, 400
  19.           # Validate and deserialize input
  20.           data, errors = user_schema.load(json_data)
  21.           if errors:
  22.               return errors, 422
  23.           user = Users.query.filter_by(email=data['email']).first()
  24.           if user:
  25.               return {'message': 'User already exists'}, 400
  26.           print(json_data['fname'])
  27.           user = Users(
  28.               fname=json_data['fname'],
  29.               lname=json_data['lname'],
  30.               email=json_data['email'],
  31.               phone=json_data['phone'],
  32.               typeid=json_data['typeid'],
  33.           )
  35.           db.session.add(user)
  36.           db.session.commit()
  38.           result = user_schema.dump(user).data
  40.           return {"status": 'success', 'data': result}, 201

答案1

得分: 1

不需要定义SQLAlchemy模型构造函数。SQLAlchemy文档 解释道：

> 使用声明式系统定义的User类
> 已经提供了一个构造函数（例如__init__()方法）
> 它会自动接受与我们映射的列匹配的关键字名称。
> 我们可以在类上定义任何明确的__init__()方法，
> 它会覆盖由声明式提供的默认方法。

在Users.py的第27行，您尝试创建Users对象

  1.           Users(
  2.               fname=json_data['fname'],
  3.               lname=json_data['lname'],
  4.               email=json_data['email'],
  5.               phone=json_data['phone'],
  6.               typeid=json_data['typeid'],
  7.           )

而在Model.py中，Users类的构造函数只接受2个参数。

  1.   class Users(db.Model):
  2.     ....
  4.       def __init__(self, users, typeid):
  5.           ...

这就是错误的来源：
TypeError: __init__() got an unexpected keyword argument 'fname'

移除__init__之后，应该可以正常工作。

英文:

It is not necessary to define SQLAlchemy model constructor. The SQLAlchemy docs explains:

> 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.

In Users.py line 27 you try to create Users object

  1.           Users(
  2.               fname=json_data['fname'],
  3.               lname=json_data['lname'],
  4.               email=json_data['email'],
  5.               phone=json_data['phone'],
  6.               typeid=json_data['typeid'],
  7.           )

Where in Model.py constructor of Users class takes only 2 arguments.

  1.   class Users(db.Model):
  2.     ....
  4.       def __init__(self, users, typeid):
  5.           ...

That's where the error comes from:
TypeError: __init__() got an unexpected keyword argument 'fname'

After removing __init__ it should work fine.

huangapple
  • 本文由 发表于 2020年1月3日 18:40:05
  • 转载请务必保留本文链接：https://go.coder-hub.com/59577085.html
  • flask
  • python
  • rest
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