Fastapi: [BUG] Error in example about connecting with SQLAlchemy

[rappongy]

Describe the bug
Facing an error with example __sql_app__ from the tutorial SQL (Relational) Databases.

  File "./sql_app/main.py", line 25, in create_user
    db_user = crud.get_user_by_email(db, email=user.email)
  File "./sql_app/crud.py", line 11, in get_user_by_email
    return db.query(models.User).filter(models.User.email == email).first()
  AttributeError: 'generator' object has no attribute 'query'

To Reproduce
Follow instruction from the example (link above):

1. Create files into _sql_app_ directory.
2. Run venv/bin/uvicorn sql_app.main:app --reload
3. http://127.0.0.1:8000/docs
4. Execute the _Create user_ operation

Environment:

• OS: Linux, Ubuntu 18.04.3 LTS
• Python 3.7.3
• FastAPI 0.39.0
• SQLAlchemy 1.3.10

[peilion]

FastAPI 0.39.0 does not support yield in dependencies, try to upgrade FastApi to 0.42.0.

or see this
https://github.com/tiangolo/fastapi/blob/78272ac1f32bce5c972633006d301d16557eee9e/docs/src/sql_databases/sql_app/main.py

[rappongy]

Thanks! This helped.

[pspierce]

I am seeing this same issue in .52 using almost verbatim the doc examples with postgres. Depends is not calling the function but returning what appears to be an instantiate Depends object.

[H0r53]

The reference previously posted by @peilion seems to no longer be a valid URL. Following the same example as the OP, I am receiving the following error: 'Depends' object has no attribute 'query'. This is because I'm using the db: Session = Depends(get_db) approach to access SessionLocal. If I attempt to get a db session by calling get_db directly, then I receive the 'generator' object has no attribute 'query' error that the OP originally mentioned. This is with FastAPI version .53

[tiangolo]

Thanks for the help here @peilion ! :clap: :bow:

Thanks for reporting back and closing the issue @rappongy :+1:

---

@pspierce and @H0r53 if you are still having problems, please create a new issue with a minimal self-contained example with the problem, that way we can check what's happening.

[osmanbaskaya]

I am seeing this same issue in .52 using almost verbatim the doc examples with postgres. Depends is not calling the function but returning what appears to be an instantiate Depends object.

@pspierce and @H0r53, Did you solve this? I am seeing in 0.58.1. I also tried: instead of using generator, returning the db directly -- same problem.

[BrainABar]

I am seeing this same issue in .52 using almost verbatim the doc examples with postgres. Depends is not calling the function but returning what appears to be an instantiate Depends object.

@pspierce and @H0r53, Did you solve this? I am seeing in 0.58.1. I also tried: instead of using generator, returning the db directly -- same problem.

from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker

engine = create_engine('postgresql://postgres:postgres@localhost:5432/postgres', echo=True)
default_session = scoped_session(sessionmaker(autocommit=False,
                                         autoflush=False,
                                         bind=engine))

def get_database():
    db = default_session()
    try:
        yield db
    finally:
        db.close()

First error I got:

AttributeError: 'Depends' object has no attribute 'query'

from database.data import get_database, scoped_session
from database.models.reference import Reference
from fastapi import Depends


def get_references(db: scoped_session = Depends(get_database())):
    references = db.query(Reference).all()
    return references

Without Depends:

AttributeError: 'generator' object has no attribute 'query'

def get_references(db: scoped_session = get_database()):