I am learning to build an API using Python, Flask and SQLAlchemy. When I started integrating SQLAlchemy into my code, any request that was trying to use SQLAchemy would just do nothing. No Error codes, it just sits there and spins. Here is the main portion of my code:
App.py
from flask import Flask
from flask_restful import Api
from flask_jwt import JWT
from security import authenticate, identity
from Resources.user import UserRegister
from Resources.item import Item, ItemList
app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = "postgresql://postgres:mypassword@localhost:5000/mydatabase"
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
app.config['PROPAGATE_EXCEPTIONS'] = True
app.secret_key = 'jose'
api = Api(app)
jwt = JWT(app, authenticate, identity)
api.add_resource(Item, '/item/<string:name>')
api.add_resource(ItemList, '/items')
api.add_resource(UserRegister, '/register')
if __name__ == '__main__':
from db import db
db.init_app(app)
app.run(port = 5000, debug = True)
db.py
from flask_sqlalchemy import SQLAlchemy
db = SQLAlchemy()
item.py-Models
from db import db
class ItemModel(db.Model):
__tablename__ = 'parts'
partid = db.Column(db.Integer, primary_key = True)
partdescript = db.Column(db.String(80))
lastcost = db.Column(db.Float(precision=2))
def __init__(self, partid, partdescript, _price):
self.partid = partid
self.partdescript = partdescript
self.price = price
def json(self):
return {'name': self.partid, 'partdescript': self.partdescript, 'price':self.price}
@classmethod
def find_by_name(cls, partid):
print("find_by_name")
#print(partid)
#print(cls.query.filter_by(partid = partid))
qry = cls.query.filter_by(partid = partid).first() # this is where it is getting stuck
return qry
def save_to_db(self):
db.session.add(self)
db.session.commit()
def delete_from_db(self):
db.session.delete(self)
db.session.commit()
item.py-Resources
from flask_restful import Resource, reqparse
from flask_jwt import jwt_required
from Models.item import ItemModel
class Item(Resource):
parser = reqparse.RequestParser()
parser.add_argument(
'partdescript',
type = str,
required = False,
help = "This field cannot be left blank!"
)
parser.add_argument(
'lastcost',
type = float,
required = True,
help = "This field cannot be left blank!"
)
#@jwt_required()
def get(self, name):
#print("get")
part = ItemModel.find_by_name(name)
#print(part)
if part:
#print("get if statement")
return part.json(), 201
return {'message': 'Part not found'}, 404
@jwt_required()
def post(self, name): #need to have the parser.add_argument for each field
if ItemModel.find_by_name(name):
return {'message': "An item with name '{}' already exists.".format(name)}, 400
data = Item.parser.parse_args()
item = ItemModel(name, data['partdescript'], data['lastcost'])
try:
item.save_to_db()
except:
return {"message": "An error occurred inserting the item."}, 500
return item.json(), 201
@jwt_required()
def delete(self, name):
item = ItemModel.find_by_name(name)
if item:
item.delete_from_db()
return {'message': 'Item deleted'}
@jwt_required()
def put(self, name):
data = Item.parser.parse_args()
item = ItemModel.find_by_name(name)
updated_item = ItemModel(name, "",data['lastcost']) #might need to put item descript in
if item is None:
item = ItemModel(name, data['lastcost'])
else:
item.lastcost = data['lastcost']
item.save_to_db()
return item.json()
class ItemList(Resource):
@jwt_required()
def get(self):
return {'items': [item.json() for item in ItemModel.query.all()]}
If I just use python to access my database correctly the requests function just fine. It is only when I am trying to use SQLAlchemy. Someone that I have been getting help from thought that it might be because I had both SQLAlchemy and direct access in my code. I converted everything to SQLAlchemy and now all of the requests just sit and spin. My old code that does not use SQLAlchemy still works.
Things I have tried: Rebooting system Uninstall and reinstall SQLAlchemy sending requests using cURL instead of Postman putting wrong database name in connection to see if I would get an error. running all applications as administrator
I put in several print statements to find where it is failing. If I remove a .first() or .all() then my code continues to run and I can print what the query is supposed to be but that also makes it so the query is not sent at all.
Any ideas why SQLAchemy would just sit and Spin?
