aedes-cached-persistence
Abstract class to write an Aedes persistence with in-process caching of subscriptions. It implements the API defined by aedes-persistence.
Install
To install aedes-cached-persistence, simply use npm:
npm install aedes-cached-persistence --saveProvided methods
CachedPersistence()instance.subscriptionsByTopic()instance.cleanSubscriptions()instance.destroy()
Implement another persistence
Inheritance
In order to reuse aedes-cached-persistence, you need to:
const CachedPersistence = require('aedes-cached-persistence')
// if you need http://npm.im/aedes-packet, it is available
// from this module as well
// const { Packet } = CachedPersistence
class MyPersistence extends CachedPersistence {
constructor(opts) {
super(opts)
}
addSubscriptions(client, subs, cb) {
// ..persistence specific implementation..
// call super._addedSubscriptions when you are done
super._addedSubscriptions(client, subs.map(mapSub), cb)
}
removeSubscriptions(client, subs, cb) {
// ..persistence specific implementation..
// call super._removedSubscriptions when you are done
super._removedSubscriptions(client, subs.map(mapSub), cb)
}
}
function mapSub (sub) {
return { topic: sub.topic }
}Tests
A persistence needs to pass all tests defined in ./abstract.js. You can import and use that test suite in the following manner:
var test = require('tape').test
var myperst = require('./')
var abs = require('aedes-cached-persistence/abstract')
abs({
test: test,
persistence: myperst
})If you require some async stuff before returning, a callback is also supported:
var test = require('tape').test
var myperst = require('./')
var abs = require('aedes-persistence/abstract')
var clean = require('./clean') // invented module
abs({
test: test,
buildEmitter: require('mymqemitter'), // optional
persistence: function build (cb) {
clean(function (err) {
cb(err, myperst())
})
}
})License
MIT