Replaced memcached with redis.

db.coffee

@@ -1,7 +1,6 @@
 config = require './config'
 mongodb = require 'mongodb'
-Memcached = require 'memcached'
-memcached = new Memcached(config.MEMCACHED_SOCKET, {maxExpiration : 86400, retries : 1})
+redisClient = require('redis').createClient(config.REDIS_SOCKET)
 
 tasksCollection = null
 devicesCollection = null
@@ -40,27 +39,22 @@ mongodb.MongoClient.connect("mongodb://#{config.MONGODB_SOCKET}/#{config.DATABAS
 
 
 getTask = (taskId, callback) ->
-  # TODO using getMulti instead of get because of possible bug
-  # in node-memcached where it sometimes returns incorrect values
-  # when under heavy load. getMulti works fine.
   tid = String(taskId)
-  memcached.getMulti([tid], (err, data) ->
-    task = data[tid]
-    if not task?
-      tasksCollection.findOne({_id : mongodb.ObjectID(tid)}, (err, task) ->
-        # TODO use err parameter in callback
-        throw new Error(err) if err?
-        callback(task)
-      )
+  redisClient.get(tid, (err, res) ->
+    return callback(err) if err
+    if res?
+      callback(err, JSON.parse(res))
     else
-      callback(task)
+      tasksCollection.findOne({_id : mongodb.ObjectID(tid)}, (err, task) ->
+        callback(err, task)
+      )
   )
 
 
 getPresets = (callback) ->
-  memcached.get(['presets', 'objects'], (err, res) ->
-    presets = res.presets
-    objects = res.objects
+  redisClient.mget('presets', 'objects', (err, res) ->
+    presets = JSON.parse(res[0])
+    objects = JSON.parse(res[1])
     if presets and objects
       callback(presets, objects)
       return
@@ -69,7 +63,7 @@ getPresets = (callback) ->
       throw err if err
       presets = p
 
-      memcached.set('presets', presets, config.PRESETS_CACHE_DURATION)
+      redisClient.setex('presets', config.PRESETS_CACHE_DURATION, JSON.stringify(presets))
       callback(presets, objects) if objects
     )
 
@@ -79,12 +73,12 @@ getPresets = (callback) ->
       for i in o
         objects[i._id] = i
 
-      memcached.set('objects', objects, config.PRESETS_CACHE_DURATION)
+      redisClient.setex('objects', config.PRESETS_CACHE_DURATION, JSON.stringify(objects))
       callback(presets, objects) if presets
     )
   )
 
 
-exports.memcached = memcached
+exports.redisClient = redisClient
 exports.getTask = getTask
 exports.getPresets = getPresets