pushd

crypto = require 'crypto' async = require 'async' Event = require('./event').Event logger = require 'winston' class Subscriber getInstanceFromToken: (redis, proto, token, cb) -> return until cb throw new Error("Missing redis connection") if not redis? throw new Error("Missing mandatory `proto' field") if not proto? throw new Error("Missing mandatory `token' field") if not token? redis.hget "tokenmap", "#{proto}:#{token}", (err, id) => if id? # looks like this subscriber is already registered redis.exists "subscriber:#{id}", (err, exists) => if exists cb(new Subscriber(redis, id)) else # duh!? the global list reference an unexisting object, fix this inconsistency and return no subscriber redis.hdel "tokenmap", "#{proto}:#{token}", => cb(null) else cb(null) # No subscriber for this token create: (redis, fields, cb, tentatives=0) -> return until cb throw new Error("Missing redis connection") if not redis? throw new Error("Missing mandatory `proto' field") if not fields?.proto? throw new Error("Missing mandatory `token' field") if not fields?.token? if tentatives > 10 # exceeded the retry limit throw new Error "Can't find free uniq id" # verify if token is already registered Subscriber::getInstanceFromToken redis, fields.proto, fields.token, (subscriber) => if subscriber? # this subscriber is already registered delete fields.token delete fields.proto subscriber.set fields, => cb(subscriber, created=false, tentatives) else # register the subscriber using a randomly generated id crypto.randomBytes 8, (ex, buf) => # generate a base64url random uniq id id = buf.toString('base64').replace(/\=+$/, '').replace(/\//g, '_').replace(/\+/g, '-') redis.watch "subscriber:#{id}", => redis.exists "subscriber:#{id}", (err, exists) => if exists # already exists, rollback and retry with another id redis.discard => return Subscriber::create(redis, fields, cb, tentatives + 1) else fields.created = fields.updated = Math.round(new Date().getTime() / 1000) redis.multi() # register subscriber token to db id .hsetnx("tokenmap", "#{fields.proto}:#{fields.token}", id) # register subscriber to global list .zadd("subscribers", 0, id) # save fields .hmset("subscriber:#{id}", fields) .exec (err, results) => if results is null # Transction discarded due to a parallel creation of the watched subscriber key # Try again in order to get the peer created subscriber return Subscriber::create(redis, fields, cb, tentatives + 1) if not results[0] # Unlikly race condition: another client registered the same token at the same time # Rollback and retry the registration so we can return the peer subscriber id redis.del "subscriber:#{id}", => return Subscriber::create(redis, fields, cb, tentatives + 1) else # done cb(new Subscriber(redis, id), created=true, tentatives) constructor: (@redis, @id) -> @info = null @key = "subscriber:#{@id}" delete: (cb) -> @redis.multi() # get subscriber's token .hmget(@key, 'proto', 'token') # gather subscriptions .zrange("subscriber:#{@id}:evts", 0, -1) .exec (err, results) => [proto, token] = results[0] events = results[1] multi = @redis.multi() # remove from subscriber token to id map .hdel("tokenmap", "#{proto}:#{token}") # remove from global subscriber list .zrem("subscribers", @id) # remove subscriber info hash .del(@key) # remove subscription list .del("#{@key}:evts") # unsubscribe subscriber from all subscribed events for eventName in events multi.zrem("event:#{eventName}:subs", @id) # count subscribers after zrem multi.zcard("event:#{eventName}:subs") multi.exec (err, results) => @info = null # flush cache # check if some events have been rendered empty emptyEvents = [] for eventName, i in events when results[4 + i + (i * 1) + 1] is 0 emptyEvents.push new Event(@redis, eventName) async.forEach emptyEvents, ((evt, done) => evt.delete(done)), => cb(results[1] is 1) if cb # true if deleted, false if did exist get: (cb) -> return until cb # returned cached value or perform query if @info? cb(@info) else @redis.hgetall @key, (err, @info) => if info?.updated? # subscriber exists # transform numeric value to number type for own key, value of info num = parseInt(value) @info[key] = if num + '' is value then num else value cb(@info) else cb(@info = null) # null if subscriber doesn't exist + flush cache set: (fieldsAndValues, cb) -> # TODO handle token update needed for Android throw new Error("Can't modify `token` field") if fieldsAndValues.token? throw new Error("Can't modify `proto` field") if fieldsAndValues.proto? fieldsAndValues.updated = Math.round(new Date().getTime() / 1000) @redis.multi() # check subscriber existance .zscore("subscribers", @id) # edit fields .hmset(@key, fieldsAndValues) .exec (err, results) => @info = null # flush cache if results && results[0]? # subscriber exists? cb(true) if cb else # remove edited fields @redis.del @key, => cb(null) if cb # null if subscriber doesn't exist incr: (field, cb) -> @redis.multi() # check subscriber existance .zscore("subscribers", @id) # increment field .hincrby(@key, field, 1) .exec (err, results) => if results[0]? # subscriber exists? @info[field] = results[1] if @info? # update cache field cb(results[1]) if cb else @info = null # flush cache # remove edited field @redis.del @key, => cb(null) if cb # null if subscriber doesn't exist getSubscriptions: (cb) -> return unless cb @redis.multi() # check subscriber existance .zscore("subscribers", @id) # gather all subscriptions .zrange("#{@key}:evts", 0, -1, 'WITHSCORES') .exec (err, results) => if results[0]? # subscriber exists? subscriptions = [] eventsWithOptions = results[1] if eventsWithOptions? for eventName, i in eventsWithOptions by 2 subscriptions.push event: new Event(@redis, eventName) options: parseInt(eventsWithOptions[i + 1], 10) cb(subscriptions) else cb(null) # null if subscriber doesn't exist getSubscription: (event, cb) -> return unless cb @redis.multi() # check subscriber existance .zscore("subscribers", @id) # gather all subscriptions .zscore("#{@key}:evts", event.name) .exec (err, results) => if results[0]? and results[1]? # subscriber and subscription exists? cb event: event options: parseInt(results[1], 10) else cb(null) # null if subscriber doesn't exist addSubscription: (event, options, cb) -> @redis.multi() # check subscriber existance .zscore("subscribers", @id) # add event to subscriber's subscriptions list .zadd("#{@key}:evts", options, event.name) # add subscriber to event's subscribers list .zadd("#{event.key}:subs", options, @id) # set the event created field if not already there (event is lazily created on first subscription) .hsetnx(event.key, "created", Math.round(new Date().getTime() / 1000)) # lazily add event to the global event list .sadd("events", event.name) .exec (err, results) => if results[0]? # subscriber exists? logger.verbose "Registered subscriber #{@id} to event #{event.name}" cb(results[1] is 1) if cb else # Tried to add a sub on an unexisting subscriber, remove just added sub # This is an exception so we don't first check subscriber existance before to add sub, # but we manually rollback the subscription in case of error @redis.multi() # remove the wrongly created subs subscriber relation .del("#{@key}:evts", event.name) # remove the subscriber from the event's subscribers list .zrem("#{event.key}:subs", @id) # check if the subscriber list still exist after previous zrem .zcard("#{event.key}:subs") .exec (err, results) => if results[2] is 0 # The event subscriber list is now empty, clean it event.delete() # TOFIX possible race condition cb(null) if cb # null if subscriber doesn't exist removeSubscription: (event, cb) -> @redis.multi() # check subscriber existance .zscore("subscribers", @id) # remove event from subscriber's subscriptions list .zrem("#{@key}:evts", event.name) # remove the subscriber from the event's subscribers list .zrem("#{event.key}:subs", @id) # check if the subscriber list still exist after previous zrem .zcard("#{event.key}:subs") .exec (err, results) => if results[3] is 0 # The event subscriber list is now empty, clean it event.delete() # TOFIX possible race condition if results[0]? # subscriber exists? wasRemoved = results[1] is 1 # true if removed, false if wasn't subscribed if wasRemoved logger.verbose "Subscriber #{@id} unregistered from event #{event.name}" cb(wasRemoved) if cb else cb(null) if cb # null if subscriber doesn't exist exports.Subscriber = Subscriber