sqlalchemy showing an error related to os.getenv() - flask

Question

I am working on sqlalchemy and there's command in it engine -
create_engine(os.getenv("DATABASE_URL")).
When I run the program it shows an error saying -
"Could not parse rfc1738 URL from string 'C:\Program Files\ PostgreSQL\10\data"
Code
import os
from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker
#engine = create_engine('sqlite://')
engine = create_engine(os.getenv("DATABASE_URL"))
db = scoped_session(sessionmaker(bind=engine))
def main():
flights = db.execute("SELECT origin, destinaiton, duration FROM flights").fetchall()
for flights in flights:
print(f"{flight.origin} to {flight.destination}, {flight.duration} minutes.")
if __name__ == "__main__":
main()
Error
Traceback (most recent call last): File "list.py", line 7, in
engine = create_engine(os.getenv("DATABASE_URL")) File "C:\Users\Amber
Bhanarkar\AppData\Local\Programs\Python\Python36\lib\site-packages\sqlalchemy\engine__init__.py",
line 424, in create_engine
return strategy.create(*args, **kwargs) File "C:\Users\Amber Bhanarkar\AppData\Local\Programs\Python\Python36\lib\site-packages\sqlalchemy\engine\strategies.py",
line 50, in create
u = url.make_url(name_or_url) File "C:\Users\Amber Bhanarkar\AppData\Local\Programs\Python\Python36\lib\site-packages\sqlalchemy\engine\url.py",
line 211, in make_url
return _parse_rfc1738_args(name_or_url) File "C:\Users\Amber Bhanarkar\AppData\Local\Programs\Python\Python36\lib\site-packages\sqlalchemy\engine\url.py",
line 270, in _parse_rfc1738_args
"Could not parse rfc1738 URL from string '%s'" % name) sqlalchemy.exc.ArgumentError: Could not parse rfc1738 URL from string
'C:\Program Files\PostgreSQL\10\data'
Please someone help me resolving this issue.

Answer 1

The engine URL shouldn't be a path to your local Postgres installation but a sting that tells SQLAlchemy how to connect to the database. It has the following format:
postgresql://username:password#server:port/databasename

Answer 2

I'm also watching course video of cs50 now. You should try to just use create_engine("your_database_url").
If you still want to use create_engine(os.getenv("DATABASE_URL")) tp process, make sure you can log in using the command line like this psql $DATABASE_URL.

Answer 3

using psql $DATABASE_URL works for me but I'm still getting the same error on create_engine("your_database_url")
(project1) C:\Users\Gregory Goufan\Downloads\CS50s Web Programming with Python and JavaScript\project1\project1\project1>psql postgresql://openpg:openpgpwd#localhost:5432/postgres
psql (9.5.8)
WARNING: Console code page (437) differs from Windows code page (1252)
8-bit characters might not work correctly. See psql reference
page "Notes for Windows users" for details.
Type "help" for help.
postgres=#
But it is true that by putting the url direct in create_engine funciton works strange thing because it is indeed a string which is returned
sqlalchemy.exc.ArgumentError: Could not parse rfc1738 URL from string ' 'postgresql://openpg:openpgpwd#localhost:5432/postgres''