The signature for synchronous backends.
This signature should be used for backends that don't expose an asynchronous interface, such as an in-memory backend or a backend that only has a blocking interface.
default_period t returns default period after which session keys will expire. Depending on the backend, this value may vary over time.
generate ?expiry ?value t will allocate a new session in the backend
t and return its associated
key. The session will expire
expiry seconds from now, defaulting to
default_period t if one is not explicitly specified.
The key should be unique, though it may not be in order to allow implementations that use randomness or hashing to conform to this interface.
clear t key removes
key from the backend
t. The backend may choose to persist the session value beyond this call, but any subsequent calls operations involving
key should behave as if
key is not present in the backend.
get t key returns the session value, if present and unexpired, together with its expiry period as of now.