FastAPI — App & Routing¶

from fastapi import FastAPI

app = FastAPI(
    title="My Service",
    version="1.0.0",
    docs_url="/docs",            # None to disable Swagger UI
    redoc_url="/redoc",          # None to disable ReDoc
    openapi_url="/openapi.json", # None to disable schema
    root_path="/api/v1",         # behind reverse proxy
)

from fastapi import FastAPI, Path, Query

app = FastAPI()


@app.get("/users/{user_id}")
async def get_user(user_id: int = Path(gt=0, description="User ID")):
    return {"user_id": user_id}


@app.get("/files/{file_path:path}")
async def read_file(file_path: str):
    return {"path": file_path}


@app.get("/items")
async def list_items(
    skip: int = Query(default=0, ge=0),
    limit: int = Query(default=20, le=100),
    search: str | None = Query(default=None, min_length=1),
    tags: list[str] = Query(default=[]),
):
    return {"skip": skip, "limit": limit, "search": search, "tags": tags}

from pydantic import BaseModel, EmailStr, Field
from fastapi import FastAPI

app = FastAPI()


class UserCreate(BaseModel):
    name: str = Field(min_length=1, max_length=100)
    email: EmailStr
    age: int | None = Field(default=None, ge=0, le=200)


class UserResponse(BaseModel):
    id: int
    name: str
    email: EmailStr

    model_config = {"from_attributes": True}


@app.post("/users", response_model=UserResponse, status_code=201)
async def create_user(user: UserCreate):
    return UserResponse(id=1, name=user.name, email=user.email)

from fastapi import FastAPI, HTTPException, status

app = FastAPI()


@app.get("/items/{item_id}", responses={404: {"description": "Not found"}})
async def get_item(item_id: int):
    if item_id > 100:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail=f"Item {item_id} not found",
        )
    return {"item_id": item_id}

from fastapi import APIRouter, FastAPI

router = APIRouter(prefix="/users", tags=["users"])


@router.get("/")
async def list_users():
    return []


@router.get("/{user_id}")
async def get_user(user_id: int):
    return {"user_id": user_id}


app = FastAPI()
app.include_router(router)

from fastapi import Cookie, FastAPI, File, Form, Header, UploadFile

app = FastAPI()


@app.get("/info")
async def read_info(
    user_agent: str | None = Header(default=None),
    session_id: str | None = Cookie(default=None),
):
    return {"user_agent": user_agent, "session_id": session_id}


@app.post("/login")
async def login(username: str = Form(), password: str = Form()):
    return {"username": username}


@app.post("/upload")
async def upload(file: UploadFile = File(description="Upload a file")):
    contents = await file.read()
    return {"filename": file.filename, "size": len(contents)}