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FastAPICache.Clear(namespace...) does not work with custom key_builder #571
Description
Hello,
I'm having an issue with FastAPICache.clear() when using a custom key_builder.
The caching itself works perfectly:
@cache(expire=300, key_builder=create_client_key_builder("clients:single"))
async def get_single_client(...):
...The key appears correctly in Redis like this:
clients:single:user:3:client_id:3:no-params
But when I try to clear it, nothing happens:
await FastAPICache.clear(
namespace=f"clients:single:user:{current_user.id}:client_id:{client_id}:no-params"
)Even though the string I'm passing is exactly the same as the key in Redis.
Right now I'm doing this and it works:
await redis_client.delete(
f"clients:single:user:{current_user.id}:client_id:{client_id}:no-params"
)Key Builder
def create_client_key_builder(namespace: str):
def builder(func, *args, **kwargs):
request = kwargs.get("request")
current_user = getattr(request.state, "user", None)
user_id = getattr(current_user, "id", "anonymous")
client_id = kwargs.get("client_id") or request.path_params.get("client_id")
query_params = request.url.query or "no-params"
return f"{namespace}:user:{user_id}:client_id:{client_id}:{query_params}"
return builder
Activity
hosamk92 commentedon Jul 28, 2026
Hello @Nickopusan13
I don't think this is a bug,
clear(namespace=...)works a bit differently than it might seem. It doesn't match your literal key string, it clears based on a prefix + namespace pattern, which is meant for clearing groups of keys that share a generated prefix, like when you're using the default key builder.Since your custom key_builder returns the exact literal key, the simpler fix is to clear it directly by key instead:
That should give you the same result as your redis_client.delete(...) workaround.
If you would like to use it with namespace you could use the following:
When using namespace in clear it woul clear all keys that starts by the namespace.