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index.js
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index.js
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var EventEmitter = require('events').EventEmitter
var inherits = require('inherits')
var async= require('async')
module.exports = Emitter
function Emitter(r, opts) {
var self = this, reconnect
if (!(this instanceof Emitter)) return new Emitter(r, opts)
opts.db = opts.db || 'emitterRethinkDB'
opts.table = opts.table || 'emitterEvents'
this.init = false
this.conn = null
this.queue = async.queue(function (task, cb) {
r.db(opts.db).table(opts.table).insert({args:task.args}).run(self.conn, function(err, obj){
err && cb(err)
r.db(opts.db).table(opts.table).get(obj.generated_keys[0]).delete().run(self.conn, function(err){
cb(err ? err : null)
})
})
}, 1)
this.queue.pause()
reconnect = require('reconnect-rethinkdb')(r, opts)
reconnect
.on('disconnect', function(err){
self.conn = null
self.queue.pause()
self.emit('disconnect', err)
})
.on('connect', function(conn){
self.conn = conn
self.emit('connect', conn)
_init(function(err){
if (err) return self.emit('error', err)
/* as of now rethinkdb doesn't let us know when
table is ready and it's time to perform operations;
using an ugly hack for now
*/
setTimeout(function(){
_listen()
self.queue.resume()
}, 2000)
})
})
.on('reconnect', function(n,d) {
self.emit('reconnect', n,d)
})
.on('fail', self.emit.bind(self, 'fail'))
.connect()
function _listen() {
var args
r.db(opts.db).table(opts.table).changes().run(self.conn, function(err, cursor) {
if (err) return self.emit('error', err)
cursor.each(function(err, data) {
if (!data.old_val) return
args = data.old_val.args
self.emit.apply(self, args)
})
})
}
function _init(cb) {
if (self.init) return cb(null)
_initDb(function(err){
if (err) return cb(err)
_initTable(function(err){
if (err) return cb(err)
self.init = true
cb(null)
})
})
}
function _initTable(cb) {
r.db(opts.db).tableList().run(self.conn, function(err, items){
if (err) return cb(err)
if (items.indexOf(opts.table) !== -1) return cb(null)
r.db(opts.db).tableCreate(opts.table).run(self.conn, function(err){
cb(err ? err : null)
})
})
}
function _initDb(cb) {
r.dbList().run(self.conn, function(err, items) {
if (err) return cb(err)
if (items.indexOf(opts.db) !== -1) return cb(null)
r.dbCreate(opts.db).run(self.conn, function(err) {
cb(err ? err : null)
})
})
}
}
Emitter.prototype.trigger = function() {
var self = this
var args = [].slice.call(arguments)
if (['connect','disconnect','reconnect','fail','error'].indexOf(args[0]) !== -1)
throw new Error('Reserved event name')
this.queue.push({args:args}, function(err){
err && self.emit('error', err)
})
}
Emitter.prototype.kill = function() {
this.queue.kill()
}
inherits(Emitter, require('events').EventEmitter)