Caching

Response caching

Sometimes it’s desirable to cache some responses, especially if these involve expensive calculations, or when polling is expected. Litestar comes with a simple mechanism for caching:

from litestar import get


@get("/cached-path", cache=True)
def my_cached_handler() -> str:
    ...

By setting cache=True in the route handler, caching for the route handler will be enabled for the ResponseCacheConfig.default_expiration.

Note

If the default default_expiration is set to None, setting up the route handler with cache=True will keep the response in cache indefinitely.

Alternatively you can specify the number of seconds to cache the responses from the given handler like so:

from litestar import get


@get("/cached-path", cache=120)  # seconds
def my_cached_handler() -> str:
    ...

If you want the response to be cached indefinitely, you can pass the config.response_cache.CACHE_FOREVER sentinel instead:

from litestar import get
from litestar.config.response_cache import CACHE_FOREVER


@get("/cached-path", cache=CACHE_FOREVER)  # seconds
def my_cached_handler() -> str:
    ...

Configuration

You can configure caching behaviour on the application level by passing an instance of ResponseCacheConfig to the Litestar instance.

Changing where data is stored

By default, caching will use the MemoryStore, but it can be configured with any Store, for example RedisStore:

from litestar.config.cache import ResponseCacheConfig
from litestar.stores.redis import RedisStore

redis_store = RedisStore(url="redis://localhost/", port=6379, db=0)

cache_config = ResponseCacheConfig(store=redis_store)

Specifying a cache key builder

Litestar uses the request’s path + sorted query parameters as the cache key. This can be adjusted by providing a “key builder” function, either at application or route handler level.

from litestar import Litestar, Request
from litestar.config.cache import ResponseCacheConfig


def key_builder(request: Request) -> str:
    return request.url.path + request.headers.get("my-header", "")


app = Litestar([], cache_config=ResponseCacheConfig(key_builder=key_builder))

from litestar import Request, get


def key_builder(request: Request) -> str:
    return request.url.path + request.headers.get("my-header", "")


@get("/cached-path", cache=True, cache_key_builder=key_builder)
def cached_handler() -> str:
    ...