[PYTHON] How to use FastAPI ③ OpenAPI

What is written

--Memo when using FastAPI (It may be wrong because it is a personal memo ...) --Excerpts related to OpenAPI behavior from the official website documentation




Build a Docker environment and check the operation

Docker FastAPI



# main.If py is in the root directory
$ uvicorn main:app --reload --host --port 8000

# main.If py is not in the root directory
$ uvicorn app.main:app --reload --host --port 8000



import uvicorn
from fastapi import FastAPI, Query, Path, Body
from typing import Optional
from pydantic import BaseModel, Field

#Description of each tag
tags_metadata = [
        "name": "users",
        "description": "Operations with users. The **login** logic is also here.",
        "name": "items",
        "description": "Manage items. So _fancy_ they have their own docs.",
        "externalDocs": {
            "description": "Items external docs",
            "url": "https://fastapi.tiangolo.com/",

items = {
    1: {"item_no": 1, "item_name": "name1", "price": 100},
    2: {"item_no": 2, "item_name": "name2", "price": 200},
    3: {"item_no": 3, "item_name": "name3", "price": 300},

users = {
    1: {"user_no": 1, "user_name": "name1", "email": "[email protected]"},
    2: {"user_no": 2, "user_name": "name2", "email": "[email protected]"},
    3: {"user_no": 3, "user_name": "name3", "email": "[email protected]"},

#Schema description, data example
class Item(BaseModel):
    name: str
    description: Optional[str] = Field(
        title="The description of the item",
    price: float = Field(
        description="The price must be greater than zero"
    tax: Optional[float] = None

    class Config:
        schema_extra = {
            "example": {
                "name": "example_name",
                "description": "example_description",
                "price": 100,
                "tax": 10,

#OpenAPI itself settings
app = FastAPI(
    title="FastAPI Sample Project",
    description="This is a very fancy project, with auto docs for the API and everything",

#Setting of each url
    summary="read items summary",
async def read_items(
    option: Optional[str] = Query(
        title="Query Parameter Title",
        description="Query Parameter Description",
    return {"items": items}

    summary="read item summary",
async def read_item(
    item_no: str = Path(
        title="Path Parameter Title",
        description="Path Parameter Description",
    return {"item": items[item_no]}

    summary="create item summary",
async def create_item(
    item_id: int,
    item: Item = Body(..., embed=True),
    results = {"item_id": item_id, "item": item}
    return results

async def read_users():
    Create an item with all the information:

    - **name**: each item must have a name
    - **description**: a long description
    - **price**: required
    - **tax**: if the item doesn't have tax, you can omit this
    - **tags**: a set of unique tag strings for this item
    -FastAPI document reflection test
    return {"users": users}

async def read_user(user_no: str):
    return {"user": users[user_no]}

if __name__ == "__main__":
    uvicorn.run(app, host="", port=8000)

Generated document


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