Cache Hash

A simple key value store where pairs can expire after a set interval

Installation

Add this to your application's shard.yml:

dependencies:
  cache_hash:
    github: samueleaton/cache-hash

Usage Example

require "cache_hash"

cache_hash = CacheHash(String).new(2.seconds)

cache_hash.set "city1", "Seattle"
sleep 1 # one second elapsed

cache_hash.set "city2", "Hong Kong"
sleep 1 # two seconds elapsed

cache_hash.get "city1" #=> nil
cache_hash.get "city2" #=> "Hong Kong"

API

`CacheHash(V)`

Defines the type(s) for the values.

Example

CacheHash(String).new(1.minute)

`.new(cache_time_span : Time::Span)`

Creates a new instance of CacheHash and sets the cache interval.

`.set(key : String, value : V)`

Adds a key/value pair to the hash, where V is the type(s) defined at CacheHash(V), and saves the time of the action.

`.get(key : String) : V | Nil`

Returns the value for the the associated key. If the pair is stale (expired) or does not exists, it returns nil. If it exists but is expired, it is deleted before returning nil.

`.purge`

Removes all key/value pairs from the hash.

`.purge_stale`

Removes all stale key/value pairs from the hash.

`.keys() : Array(String)`

Runs purge_stale and returns an array of all the the non-stale keys.

`.fresh?(key : String) : Bool`

Returns true if the key/value pair exists and is not stale. If the pair is stale (expired) or does not exists, it returns false. If it exists but is expired, it is deleted before returning false.

`.time(key : String) : Time`

Returns the time the key/value pair was cached. If the pair is stale (expired) or does not exists, it returns nil. If it exists but is expired, it is deleted before returning nil.