Cache

When user give his api key to access your services, you often need to verify it against the stored hash. You must calculate the hash of the provided key and compare it to the stored hash. This operation can be computationally expensive, especially if you are using strong hashing algorithms like Argon2 or bcrypt. To improve performance, you can implement a caching layer that stores the results of previous hash verifications. This way, if the same API key is verified multiple times, you can retrieve the result from the cache instead of recalculating the hash each time.

We use aiocache to provide caching capabilities. This library have agnostic backends (in-memory, redis, memcached, etc.) and supports async operations.

Example

This is the canonical example from examples/example_inmemory_env.py:

Always set a pepper

The default pepper is a placeholder. Set API_KEY_PEPPER (or pass it explicitly to the hashers) in every environment.

import asyncio
import os

from fastapi_api_key import ApiKeyService
from fastapi_api_key.hasher.argon2 import Argon2ApiKeyHasher
from fastapi_api_key.repositories.in_memory import InMemoryApiKeyRepository

# Set env var to override default pepper
# Using a strong, unique pepper is crucial for security
# Default pepper is insecure and should not be used in production
pepper = os.getenv("API_KEY_PEPPER")
hasher = Argon2ApiKeyHasher(pepper=pepper)

# default hasher is Argon2 with a default pepper (to be changed in prod)
repo = InMemoryApiKeyRepository()
service = ApiKeyService(
    repo=repo,
    hasher=hasher,
)
# You can use load_dotenv for loading from .env
# from dotenv import load_dotenv
# load_dotenv()

# Ensure that you respect the format of service
os.environ["API_KEY_DEV"] = "ak-92f5326fb9b44ab7-fSvBMig0r2vY3WR2SmGoZwM949loPU7Yy1JkjIz3RzfCEkQrprQWqQuToLbM2FzN"


async def main():
    # Load api keys from os.environ
    await service.load_dotenv()  # envvar_prefix="API_KEY_"

    # Get api key for tests purposes
    api_key = os.environ["API_KEY_DEV"]

    verified = await service.verify_key(api_key)
    print("Verified key belongs to:", verified.name)


asyncio.run(main())