I am following the factory design pattern. In the WSGI.py file, why does print(db) prints
<SQLAlchemy engine=None>
I have attached the app to db with db.init_app(app) command in MAIN.py file. Shouldn't the output be
<SQLAlchemy engine= "sqlite:///site.db">
My WSGI.py file
from main import create_app, db
app = create_app("sqlite:///site.db")
print(db)
if __name__ == "__main__" :
app.run(debug=True)
My MAIN.py file
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
db = SQLAlchemy()
def create_app(URI) :
app = Flask(__name__)
app.config["SQLALCHEMY_DATABASE_URI"] = URI
db.init_app(app)
return app
Related
I am making an API with Flask-RESTFUL, but when I make the POST
http://127.0.0.1:5000/bot?id_articulo=1&url_articulo=www.wiki.org
I get the message
"message": "The browser (or proxy) sent a request that this server could not understand."
My python code is
from flask import Flask
from flask_restful import Resource, Api, reqparse
import pandas as pd
app = Flask(__name__)
api = Api(app)
class Bot(Resource):
def post(self):
parser = reqparse.RequestParser()
parser.add_argument('id_articulo' , required=True, type=int)
parser.add_argument('url_articulo', required=True, type=str)
args = parser.parse_args()
print(args)
data_articulo = pd.read_csv('articulos.csv')
print(data_articulo)
if args['url_articulo'] in list(data_articulo['url']):
return {
'mensage': f"El artículo '{args['url_articulo']}' ya existe."
}, 409
else:
nueva_columna = pd.DataFrame({
'id_articulo': [args['id_articulo']],
'url': [args['url_articulo']],
})
data_articulo = data_articulo.append(nueva_columna, ignore_index=True)
data_articulo.to_csv('articulos.csv', index=False)
return {'data': data_articulo.to_dict()}, 200
api.add_resource(Bot, '/bot', methods=['POST'])
if __name__ == '__main__':
app.run()
Now, I noticed that the error message is thrown only when I am in a virtual environment whose requirements.txt is
aniso8601==9.0.1
click==8.1.3
colorama==0.4.5
Flask==2.1.2
Flask-RESTful==0.3.9
importlib-metadata==4.12.0
itsdangerous==2.1.2
Jinja2==3.1.2
joblib==1.1.0
MarkupSafe==2.1.1
numpy==1.23.1
pandas==1.4.3
python-dateutil==2.8.2
pytz==2022.1
six==1.16.0
Werkzeug==2.1.2
zipp==3.8.0
By this far, I don't have a clue about what is going on and it makes me think that the flask_restful library have issues with virtual environments and I would like to know how to make this work properly in one.
I want to deploy my project on pythonanywhere. Error.log says that server or machine is unable to open my database. Everything works fine on my local machine. I watched a video of Pretty Printed from YouTube
This how I initialize in app.py. This what I got from error.log
db_session.global_init("db/data.sqlite")
this in db_session:
def global_init(db_file):
global __factory
if __factory:
return
if not db_file or not db_file.strip():
raise Exception("Необходимо указать файл базы данных.")
conn_str = f'sqlite:///{db_file.strip()}?check_same_thread=False'
print(f"Подключение к базе данных по адресу {conn_str}")
engine = sa.create_engine(conn_str, echo=False)
__factory = orm.sessionmaker(bind=engine)
from . import __all_models
SqlAlchemyBase.metadata.create_all(engine)
def create_session() -> Session:
global __factory
return __factory()
last thing is my wsgi.py:
import sys
path = '/home/r1chter/Chicken-beta'
if path not in sys.path:
sys.path.append(path)
import os
from dotenv import load_dotenv
project_folder = os.path.expanduser(path)
load_dotenv(os.path.join(project_folder, '.env'))
import app # noqa
application = app.app()
Usually errors like this on PythonAnywhere are due to providing relative path instead of absolute path.
I have a Vue frontend that uses Axios to POST to my Flask API. I've registered flask_cors to my Flask instance but I'm still get a CORS error.
flask_cors registered in app/__init__.py
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_migrate import Migrate
from config import Config
from flask_marshmallow import Marshmallow
from flask_cors import CORS
app = Flask(__name__)
app.config.from_object(Config)
cors = CORS(app)
db = SQLAlchemy(app)
migrate = Migrate(app, db)
ma = Marshmallow(app)
from . import routes, models
app/routes.py
from flask import request, jsonify, current_app
from . import app, db
from .models import SetAnon
#app.route('/sets', methods=['POST'])
def sets():
data = request.get_json()
_set = SetAnon(
col1=data['somedata']
)
db.session.add(_set)
db.session.commit()
return "set saved", 201
Vue frontend is making POST request with axios:
import axios from 'axios'
const API_URL = 'http://127.0.0.1:5000'
export function saveSet(set) {
return axios.post(`${API_URL}/sets/`, set)
}
Getting this error in browser console
xhr.js?ec6c:172 OPTIONS http://127.0.0.1:5000/sets/ 404 (NOT FOUND)
Access to XMLHttpRequest at 'http://127.0.0.1:5000/sets/' from origin 'http://localhost:8080' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: It does not have HTTP ok status.
Looks like an issue with trailing backslash. Your routes.py defines the route as '/sets' however the frontend is calling '/sets/'.
Change the routes.py to this and it should work -
from flask import request, jsonify, current_app
from . import app, db
from .models import SetAnon
#app.route('/sets/', methods=['POST']) # Added trailing backslash
def sets():
data = request.get_json()
_set = SetAnon(
col1=data['somedata']
)
db.session.add(_set)
db.session.commit()
return "set saved", 201
I am learning Flask by following Miguel Ginsberg mega tutorial chapter 4. When I run any Flask command from the Anaconda command panel I get an error that includes "Neither SQLALCHEMY_DATABASE_URI nor SQLALCHEMY_BINDS is set." and as a result an SQLite database is created in memory.
But I have created a Config object that sets SQLALCHEMY_DATABASE_URI, SECRET_KEY and SQLALCHEMY_TRACK_MODIFICATIONS, and have tested the python separately, and it all works.
I have tried everything I can think of including testing snippets of code separately, at least 8 hours searching the web, and trawling though Ginsberg's posts, nothing works. One person Graham (post #29) seems to have had the same problem but Ginsberg does not give a useful answer.
Here is my app init code
__init__
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_migrate import Migrate
from config import Config
app = Flask(__name__)
app.config.from_object(Config)
db = SQLAlchemy(app)
migrate = Migrate(app, db)
from app import routes, models
Here is my config, it works when run separately.
import os
basedir = os.path.abspath(os.path.dirname(__file__))
class Config(object):
SECRET_KEY = os.environ.get('SECRET_KEY') or 'you-will-never-guess'
SQLALCHEMY_DATABASE_URI = os.environ.get('DATABASE_URL') or \
'sqlite:///' + os.path.join(basedir, 'app.db')
SQLALCHEMY_TRACK_MODIFICATIONS = False
For completeness here are my routes and models
from flask import render_template, flash, redirect, url_for
from app import app
from app.forms import LoginForm
#app.route('/')
#app.route('/index')
def index():
user = {'username': 'Miguel'}
posts = [
{
'author': {'username': 'John'},
'body': 'Beautiful day in Portland!'
},
{
'author': {'username': 'Susan'},
'body': 'The Avengers movie was so cool!'
}
]
return render_template('index.html', title='Home', user=user, posts=posts)
#app.route('/login', methods=['GET', 'POST'])
def login():
form = LoginForm()
if form.validate_on_submit():
flash('Login requested for user {}, remember_me={}'.format(
form.username.data, form.remember_me.data))
return redirect(url_for('index'))
return render_template('login.html', title='Sign In', form=form)
and
from datetime import datetime
from app import db
class User(db.Model):
id = db.Column(db.Integer, primary_key=True)
username = db.Column(db.String(64), index=True, unique=True)
email = db.Column(db.String(120), index=True, unique=True)
password_hash = db.Column(db.String(128))
posts = db.relationship('Post', backref='author', lazy='dynamic')
def __repr__(self):
return '<User {}>'.format(self.username)
class Post(db.Model):
id = db.Column(db.Integer, primary_key=True)
body = db.Column(db.String(140))
timestamp = db.Column(db.DateTime, index=True, default=datetime.utcnow)
user_id = db.Column(db.Integer, db.ForeignKey('user.id'))
def __repr__(self):
return '<Post {}>'.format(self.body)
What should happen is that when I run a command like
> flask db init
or
> flask db migrate -m "users table"
the command should complete successfully because SQLALCHEMY_DATABASE_URI should equal the path of the app and the SQLite database should be app.db.
Instead I get error messages stating SQLALCHEMY_DATABASE_URI is not set and that therefore SQLALCHEMY_DATABASE_URI has been set to "sqlite:///:memory:"
My app needs a persistent database! Why isn't SQLALCHEMY_DATABASE_URI and SQLALCHEMY_TRACK_MODIFICATIONS being set?
this problem has gone away by itself, but since others may experience it I decided to describe the work-around I used to save them some frustration. I think the original problem may have been due to the sequence in which I was importing packages/modules and initiating classes/objects into my __init__ method.
The workaround is to comment out the original config statement and directly set the config variables, including the SQLite database, in __init__.
### app.config.from_object(Config)
app.config["SECRET_KEY"] = os.environ.get('SECRET_KEY') or 'you-will-never-guess'
app.config["SQLALCHEMY_DATABASE_URI"] = os.environ.get('DATABASE_URL') or \
'sqlite:///' + 'C:\\...path...\\app.db'
app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = False
...
The workaround can probably be backed off a little by using
import os
basedir = os.path.abspath(os.path.dirname(__file__))
...
SQLALCHEMY_DATABASE_URI = os.environ.get('DATABASE_URL') or \
'sqlite:///' + os.path.join(basedir, 'app.db')
...
I am trying to set up Django & Celery & Rabbit for the first time following this tutorial. I am using Django 2.0 Celery 4.2.0 and Rabbit on Windows
I am getting the error: celery.exceptions.NotRegistered: 'GeneratePDF'
I have set up as follows:
in my init.py:
from __future__ import absolute_import, unicode_literals
import celery
from .celery import app as celery_app
__all__ = ['celery_app']
in my celery.py:
from __future__ import absolute_import, unicode_literals
import os
from celery import Celery
from django.conf import settings
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'abc.settings')
app = Celery('abc')
app.config_from_object('django.conf:settings', namespace='CELERY')
app.autodiscover_tasks(lambda: settings.INSTALLED_APPS)
#app.task(bind=True)
def debug_task(self):
print('Request: {0!r}'.format(self.request))
in my tasks.py:
from celery import shared_task
from abc.celery import app
#shared_task(name='GeneratePDF')
class GeneratePDF(View):
def get(self, request, *args, **kwargs):
....
in my views.py:
from abc.tasks import GeneratePDF
#method_decorator(login_required, name='dispatch')
class ClientProfilePDF(RedirectView):
def get(self, request, *args, **kwargs):
GeneratePDF.delay(request)
return HttpResponseRedirect('/home/')
in my settings.py:
CELERY_BROKER_URL = 'amqp://localhost'
CELERY_ACCEPT_CONTENT = ['json']
CELERY_RESULT_BACKEND = 'django-db'
CELERY_TASK_SERIALIZER = 'json'
CELERY_RESULT_SERIALIZER = 'json'
CELERY_TIMEZONE = 'Australia/Sydney'
CELERY_IMPORTS = ('abc.tasks',)
Can anyone point me in the right direction as to where I am going wrong and why I am getting this error? Any help is much appreciated!
Two quick things:
No need for any parameters to app.autodiscover_tasks() Celery alreayd knows how to use settings.INSTALLED_APPS.
The #shared_task decorator is for tasks that live in apps that do not have their own celery.py file that instantiates an app. From the looks of it, your tasks.py file lives in the same django app as the celery.py file. In this case, you should use #app.task and not #shared_task.
before you start, you can get a list of registered tasks by doing celery -A myapp inspect registered. That will let you see if your GeneratePDF task is registered or not.