https://github.com/hyzyla/fastapi-async-sqlalchemy-orm
FastAPI + async SQLAlchemy ORM + async_scoped_session
https://github.com/hyzyla/fastapi-async-sqlalchemy-orm
Last synced: 14 days ago
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FastAPI + async SQLAlchemy ORM + async_scoped_session
- Host: GitHub
- URL: https://github.com/hyzyla/fastapi-async-sqlalchemy-orm
- Owner: hyzyla
- License: mit
- Created: 2022-06-28T08:46:00.000Z (over 3 years ago)
- Default Branch: main
- Last Pushed: 2022-06-28T18:37:01.000Z (over 3 years ago)
- Last Synced: 2025-09-11T19:55:21.859Z (about 1 month ago)
- Language: Python
- Size: 15.6 KB
- Stars: 4
- Watchers: 1
- Forks: 0
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE.md
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README
# FastAPI + async SQLAlchemy ORM + async_scoped_session example
## Features:
* Async FastAPI
* Async SQLAlchemy ORM
* async_scoped_session (you can access session by global variable)
## Run
```shell
poetry install
poetry run uvicorn app.main:app
```
# How to start session
Session will be started automatically on a first request to database: commit, query, delete, etc
```python
from fastapi import FastAPI
from app import db, models
app = FastAPI()
@app.post("/todo")
async def create_todo():
todo = models.Todo()
db.session.add(todo)
# new session will be created automatically here
# and will be removed automatically by SQLAlchemyMiddleware
await db.session.commit()
```
# How it works
```
Web Server Web Framework SQLAlchemy ORM Code
-------------- -------------- ------------------------------
startup -> Web framework # Session registry is established
initializes # file: app/db.py
AsyncSessionFactory = sessionmaker(
bind=engine,
class_=AsyncSession,
)
session = async_scoped_session(
session_factory=AsyncSessionFactory,
scopefunc=session_scope.get_session_context,
)
incoming
web request -> web request -> # SQLAlchemyMiddleware create new scoped context.
# That do nothing with ORM and the database itself,
# it's just a marker for SQLAlchemy to create a new
# instance of AsyncSession if some make some query
# using `session` created during startup.
# file: app/middlewares.py
with session_scope.set_scoped_context():
...
# the Session registry can otherwise
# be used at any time, creating the
# request-local AsyncSession() if not present,
# or returning the existing one
# file: app/main.py
await db.session.query(MyClass) # ...
await db.session..add(some_object) # ...
# if data was modified, commit the
# transaction
await db.session.commit()
web request ends -> # SQLAlchemyMiddleware at the end of the request
# removes a session from the registry. Also
# context manager `with session_scope.set_scoped_context()`
# removes the indicator created at the beginning of
# the request.
# file: app/middlewares.py
db.session.remove()
sends output <-
outgoing web <-
response
```