Fast API

WSGI vs ASGI

WSGI

ASGI

特長

from typing import List, Dict
from datetime import date

from pydantic import BaseModel

# Declare a variable as a str
# and get editor support inside the function
def main(user_id: str):
    return user_id

# A Pydantic model
class User(BaseModel):
    id: int
    name: str
    joined: date

設定

pip install fastapi
pip install uvicon[standard]

//서버 실행 localhost:8000에서 확인 가능
uvicorn main:app --reload

main: the file main.py (the Python "module").
app: the object created inside of main.py with the line app = FastAPI().
--reload: make the server restart after code changes. Only do this for development.

뒤쪽에 붙은 --reload 옵션은 hot reloading 기능으로 소스 코드가 수정되면 서버를 바로 재시작하는 
기능으로 개발 환경에서 활용하면 좋다.

きほんコード

from typing import Optional
from fastapi import FastAPI

app = FastAPI()

@app.get("/")
def read_root():
  return {"hello":"world"}

@app.get("/items/{item_id}")
def read_item(item_id:int, q:Optional[str]=None):
  return{"item_id":item_id, "q":q}

Receives HTTP requests in the paths / and /items/{item_id}.
Both paths take GET operations (also known as HTTP methods).
The path /items/{item_id} has a path parameter item_id that should be an int.
The path /items/{item_id} has an optional str query parameter q.

@app.get("/")
async def read_root():
  return {"hello":"world"}

@app.put("/items/{item_id}")
def update_item(item_id:int, item:Item):
  return { "item_name" : item.name, "item_id" : item_id }

//item 타입이 지정되어 있기 때문에 editor에서 auto-complete이 가능하다.
/docs로 접속 후 try it out 을 통해 parameter를 넣어주어 테스트한다.

Validate that there is an item_id in the path for GET and PUT requests.
Validate that the item_id is of type int for GET and PUT requests.
If it is not, the client will see a useful, clear error.
Check if there is an optional query parameter named q (as in http://127.0.0.1:8000/items/foo?q=somequery) for GET requests.
As the q parameter is declared with = None, it is optional.
Without the None it would be required (as is the body in the case with PUT).
For PUT requests to /items/{item_id}, Read the body as JSON:
Check that it has a required attribute name that should be a str.
Check that it has a required attribute price that has to be a float.
Check that it has an optional attribute is_offer, that should be a bool, if present.
All this would also work for deeply nested JSON objects.
Convert from and to JSON automatically.
Document everything with OpenAPI, that can be used by:
Interactive documentation systems.
Automatic client code generation systems, for many languages.
Provide 2 interactive documentation web interfaces directly.