Shared Cache

Allow applications share cache-state and data over Redis.

Usage

``
function update_info(cache_key, next) {
db.findOne({}, next)
}

Cache = require('shared-cache')
info = new Cache('caching key', true, update_info)

possibly_stale = info.get();
info.get(function(err, definitely_not_stale) {
...
})
``

Methods

get( [callback] )

This function both returns and executes a callback.
- In the event the data is not stale, both will receive the same value.
- If the data is stale, the return will be the stale value whilst the callback is held until the data is available.

set( data, broadcast = true )

Update the value of this cache, optionally broadcasting the new value to other instances. This marks the data as not stale.

update( callback )

Add the callback onto a queue to be fired when the update_callback returns, and call the update_callback if it hasn't already been called.

stale( broadcast = true )

Mark this data as stale. If auto_update is true then it update_callback is fired. If broadcast is true, other instances are notified to update their caches.