FastAPI¶

https://fastapi.tiangolo.com/tutorial

FastAPI is an ASGI framework

• the resulting app object doesn't talk HTTP directly,

• it just receives dictionaries and stuff passed by the ASGI server,

• and that's how it handles the rest.

You need something to pass those arguments to the FastAPI app. It could be Uvicorn, Hypercorn, Daphne... etc.

https://github.com/tiangolo/fastapi/issues/2062

• FastAPI is based on Starlette, Starlette is an ASGI micro-framework/toolkit.

• Uvicorn is made/maintained by the same developer(s) as Starlette.

• They are not tightly coupled or depend on each other in any way, but are the natural closest match.

By default, if you install with pip install uvicorn[standard] that will include and use Uvloop, a drop-in replacement for the asyncio loop, with very high performance. You don't have to do anything in your code to use it, just install uvicorn[standard].

That Uvloop thing is what gives all the performance to anything (or almost anything) in async Python that has high performance. So, chances are Uvloop would give the best performance.

run¶

if __name__ == '__main__':
    uvicorn.run('api.main:app', host='127.0.0.1', port=8000)

bigger application structure¶

https://fastapi.tiangolo.com/tutorial/bigger-applications/

model¶

https://fastapi.tiangolo.com/tutorial/body/

https://realpython.com/fastapi-python-web-apis/

• request body is the data sent by client to server.

• response body is the data the API sends back to the client.

If a parameter is not present in the path and it also uses Pydantic BaseModel, FastAPI automatically considers it as a request body.

FastAPI will read the incoming request payload as JSON and convert the corresponding data types if needed. Also, it will perform validation and return an appropriate error response.

postgresql¶

https://dev.to/jbrocher/fastapi-testing-a-database-5ao5

https://www.educative.io/answers/how-to-use-postgresql-database-in-fastapi

https://ahmed-nafies.medium.com/fastapi-with-sqlalchemy-postgresql-and-alembic-and-of-course-docker-f2b7411ee396

test¶

https://fastapi.tiangolo.com/tutorial/testing/

from fastapi import FastAPI
from fastapi.testclient import TestClient

app = FastAPI()
@app.get("/")
async def read_main():
    return {"msg": "Hello World"}
client = TestClient(app)

def test_read_main():
    response = client.get("/")
    assert response.status_code == 200
    assert response.json() == {"msg": "Hello World"}