casbin-fastapi-decorator-file

File-based enforcer provider with hot-reload for casbin-fastapi-decorator.

Provides CachedFileEnforcerProvider — loads the casbin Enforcer once from model.conf + policy.csv and automatically reloads when either file changes on disk (via watchdog).

Install

pip install casbin-fastapi-decorator-file

Usage

from contextlib import asynccontextmanager
from fastapi import FastAPI, HTTPException
from casbin_fastapi_decorator import PermissionGuard
from casbin_fastapi_decorator_file import CachedFileEnforcerProvider

provider = CachedFileEnforcerProvider(
    model_path="casbin/model.conf",
    policy_path="casbin/policy.csv",
)

@asynccontextmanager
async def lifespan(app: FastAPI):
    async with provider:   # starts file watcher
        yield              # stops file watcher on shutdown

guard = PermissionGuard(
    user_provider=get_current_user,
    enforcer_provider=provider,
    error_factory=lambda *_: HTTPException(403, "Forbidden"),
)

app = FastAPI(lifespan=lifespan)

@app.get("/articles")
@guard.require_permission("articles", "read")
async def list_articles(): ...

Any change to model.conf or policy.csv is detected automatically — the enforcer reloads on the next request with zero downtime.