Flask Blueprints: RuntimeError Application not registered on db -

Flask Blueprints: RuntimeError Application not registered on db -

ive been going @ several hours im afraid still don't gronk flask app context , how app should implemented blueprints.

ive taken @ this , this , have tried few different recommendations there must wrong basic approach.

i have 1 'main' design setup under next pj structure:

project/ app/ main/ __init__.py routes.py forms.py helper.py admin/ static/ templates/ __init__.py models.py

app/init.py:

from flask import flask config import config flask.ext.sqlalchemy import sqlalchemy flask.ext.bootstrap import bootstrap db = sqlalchemy() bootstrap = bootstrap() def create_app(config_version='default'): app = flask(__name__) app.config.from_object(config[config_version]) bootstrap.init_app(app) .main import main main_blueprint app.register_blueprint(main_blueprint) db.init_app(app) homecoming app

app/main/init.py

from flask import design main = blueprint('main',__name__) . import routes, helper

app/main/helper.py

#!/usr/bin/env python . import main ..models import sku, category, db flask import current_app def get_categories(): cat_list = [] cat in db.session.query(category).all(): cat_list.append((cat.id,cat.category)) homecoming cat_list

everything worked fine until created get_categoriesfunction in helpers.py pull dynamic list select form in app/main/forms.py. when fireup wsgi, however, error:

runtimeerror: application not registered on db instance , no application bound current context

it appear db referenced in helper not associated app context when seek create 1 within function, has not worked.

what doing wrong , there improve way organize helper functions when using blueprints?

documentation on database contexts here here.

my first thought weren't calling db.init_app(app), corrected in comments.

in app/main/helper.py, you're importing database via from ..models import sku, category, db. database object not have been initialized app you've created.

the way i've gotten around having file, shared.py in root directory. in file, create database object,

from flask.ext.sqlalchemy import sqlalchemy db = sqlalchemy()

in app/init.py, don't create new db object. instead, do

from shared import db db.init_app(app)

in place want utilize db object, import shared.py. way, object in shared file have been initialized app context, , there's no chance of circular imports (which 1 of problems can run having db object outside of app-creating file).

flask-sqlalchemy flask