How do you control HTTP status codes and return custom responses in FastAPI?

from fastapi import FastAPI, HTTPException, status
from fastapi.responses import JSONResponse, Response, FileResponse

app = FastAPI()

fake_db = {1: {"name": "Foo"}, 2: {"name": "Bar"}}

# Set default success status code
@app.post("/items", status_code=status.HTTP_201_CREATED)
def create_item(name: str):
    return {"name": name}

# Raise HTTP errors
@app.get("/items/{item_id}")
def get_item(item_id: int):
    if item_id not in fake_db:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail=f"Item {item_id} not found",
            headers={"X-Error": "Item missing"},  # custom header on error
        )
    return fake_db[item_id]

# Custom JSONResponse for full control
@app.get("/custom")
def custom_response():
    return JSONResponse(
        status_code=200,
        content={"message": "ok"},
        headers={"X-Custom": "value"},
    )

# 204 No Content (no response body)
@app.delete("/items/{item_id}", status_code=status.HTTP_204_NO_CONTENT)
def delete_item(item_id: int):
    fake_db.pop(item_id, None)
    return Response(status_code=204)