I am trying to create an API to fetch data from my Atlas MongoDB using Flask. I was following this tutorial https://www.mongodb.com/compatibility/setting-up-flask-with-mongodb
However I get the following Error when trying to get some data from my database:
File "C:\Users\salad\PycharmProjects\crypto_project\crypto\db.py", line 59, in get_currencies
total_num_currencies = db.prices.count_documents(pipeline[0])
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'prices'
this is how I create the global db:
def get_db():
"""Configuration method to return db instance"""
# All database access is routed through the global “db” object initialising the PyMongo client.
db = getattr(g, "coin_markets", None) # is equivalent to g._database
if db is None:
# The special variable object “g” is used here to define the PyMongo database in the global application context.
db = g.coin_markets = PyMongo(current_app).db
return db
db = LocalProxy(get_db)
In my run.py I config the app to use my variable in .env which contains the connection string to my mongodb:
from crypto.factory import create_app
from crypto.credentials.creds import DB_CONNECTION
if __name__ == "__main__":
app = create_app()
app.config['DEBUG'] = True
app.config['MONGO_URI'] = DB_CONNECTION
app.run()
if I print app.config['MONGO_URI'] I get the connection string so I don't understand why I get NoneType.
if it helps I use a factory pattern to create the app:
import os
from flask import Flask, render_template
from flask.json import JSONEncoder
from flask_cors import CORS
from bson import json_util, ObjectId
from datetime import datetime, timedelta
from crypto.api.currencies import currencies_api_v1
def create_app():
app = Flask(__name__)
CORS(app)
app.register_blueprint(currencies_api_v1)
@app.route('/', defaults={'path': ''})
@app.route('/<path:path>')
def serve(path):
return render_template('index.html')
return app
