I have a very simple Flask RESTful API that I have built following the Packt book "Python API Development Fundamentals". I can successfully get data from the DB but I'm having trouble posting data.
I am using Flask, SQLAlchemy, and flask_restful, and a Microsoft Server Management Studio local database. I am currently getting an error ("name 'user_schema' is not defined.") in the user.py resource when trying to insert an entry into the Users table. A user is only an ID, Name, Age.
I have never use Marshmallow before and I'm not sure what I'm doing wrong.
I am trying to create a new user by entering this into the console using httpie:
http POST localhost:5000/users Name="Kyle" Age="22"
Error
[2021-03-31 10:44:40,944] ERROR in app: Exception on /users [POST]
Traceback (most recent call last):
File "c:\users\e096752\documents\cole's projects\flask projects\testproj\venv\lib\site-packages\flask\app.py", line 1950, in full_dispatch_request
rv = self.dispatch_request()
File "c:\users\e096752\documents\cole's projects\flask projects\testproj\venv\lib\site-packages\flask\app.py", line 1936, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "c:\users\e096752\documents\cole's projects\flask projects\testproj\venv\lib\site-packages\flask_restful\__init__.py", line 468, in wrapper
resp = resource(*args, **kwargs)
File "c:\users\e096752\documents\cole's projects\flask projects\testproj\venv\lib\site-packages\flask\views.py", line 89, in view
return self.dispatch_request(*args, **kwargs)
File "c:\users\e096752\documents\cole's projects\flask projects\testproj\venv\lib\site-packages\flask_restful\__init__.py", line 583, in dispatch_request
resp = meth(*args, **kwargs)
File "C:\Users\e096752\Documents\Cole's Projects\Flask Projects\testProj\resources\users.py", line 34, in post
data, errors = user_schema.load(data=json_data)
NameError: name 'user_schema' is not defined
127.0.0.1 - - [31/Mar/2021 10:44:40] "POST /users HTTP/1.1" 500 -
users.py resource
from flask import request
from flask_restful import Resource
from http import HTTPStatus
from flask import jsonify
from sqlToJson import convert_sqlaLchamy_to_json
from models.Users import User, userList
from schemas.user import UserSchema
class User_List_Resource(Resource):
user_schema = UserSchema()
def get(self):
users = User.query.all()
data = jsonify(convert_sqlaLchamy_to_json(users))
return data
def post(self):
#Non-marshmallow approach gives error: "Object of type User is not JSON serializable"
# json_data = request.get_json()
# user = User(Name=json_data['Name'],
# Age=json_data['Age'])
# return jsonify(user), HTTPStatus.CREATED
#Marshmallow approach gives error: "line 36, name 'user_schema' is not defined."
json_data = request.get_json()
data, errors = user_schema.load(data=json_data)
if errors:
return {'message': 'Name already exists'}, HTTPStatus.BAD_REQUEST
user = User(**data)
user.save()
return user_schema.dump(user).data, HTTPStatus.CREATED
Users.py model
from extensions import db
from flask_marshmallow import Marshmallow
userList = []
def get_last_id():
if userList:
lastUser = userList[-1]
else:
return 1
return lastUser.id + 1
class User(db.Model):
__tablename__ = 'Users'
ID = db.Column(db.Integer, primary_key=True)
Name = db.Column(db.String(50))
Age = db.Column(db.Integer)
Users.py schema
from marshmallow import Schema, fields
class UserSchema(Schema):
class Meta:
ordered = True
Name = fields.String(required=True)
Age = fields.Integer(required=True)
app.py
from flask import Flask, render_template
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy import create_engine
from flask_restful import Resource, Api
from flask import jsonify
import json
from sqlToJson import convert_sqlaLchamy_to_json
import datetime
from flask_restful import Api
from config import Config
from extensions import db
from models.Case_Log import Case_Log
from resources.case_log import Case_Log_List_Resource
from models.Users import User
from resources.users import User_List_Resource
from resources.home import Home_Resource
def create_app():
app = Flask(__name__)
app.config.from_object(Config)
register_extensions(app)
register_resources(app)
return app
def register_extensions(app):
db.init_app(app)
def register_resources(app):
api = Api(app)
#Add all resources as routes
api.add_resource(Home_Resource, '/')
api.add_resource(Case_Log_List_Resource, '/case_logs')
api.add_resource(User_List_Resource, '/users')
if __name__ == '__main__':
app = create_app()
app.run()
Here is my project structure if it helps:
And here is a pic of the database table if that helps at all:
