Ocsipersist is a collection of libraries defining a unified frontend for a number of key/value storage implementations. It is used pervasively in Ocsigen/Eliom to handle sessions and persistent references, but can be used as a standalone library or as an extension for Ocsigen Server.
Three backends currently exist:
You choose a backend by installing the corresponding package (ocsipersist-sqlite, ocsipersist-dbm or ocsipersist-pgsql); the unified frontend is the same in every case.
The storage frontend is documented in module Ocsipersist. It defines several interfaces:
Ref — the simplest to use: persistent references;Store — a lower-level interface for persistent values;Polymorphic — a polymorphic table (using Marshal);Functorial — a type-safe table built from a value description.See Ocsipersist for the full frontend, and Ocsipersist_lib for the backend-independent signatures and functors shared by every backend.
Each backend ships an Ocsipersist_settings library to configure storage from OCaml, and an optional ocsipersist-*-config package to configure it from Ocsigen Server's configuration file: