Use variable to store active sessions

Keep session data in process for as long as the TCP connectoin is
open. Use redis if connection closes before the session is over.

lib/cwmp.coffee

@@ -40,6 +40,7 @@
 
 util = require 'util'
 zlib = require 'zlib'
+crypto = require 'crypto'
 mongodb = require 'mongodb'
 
 config = require './config'
@@ -94,15 +95,12 @@ inform = (currentRequest, cwmpRequest) ->
       cwmpVersion : currentRequest.sessionData.cwmpVersion
     })
 
-    session.save(currentRequest.sessionData, (err, sessionId) ->
-      throw err if err
-      if !!cookiesPath = config.get('COOKIES_PATH', currentRequest.sessionData.deviceId)
-        res.headers['Set-Cookie'] = "session=#{sessionId}; Path=#{cookiesPath}"
-      else
-        res.headers['Set-Cookie'] = "session=#{sessionId}"
+    if !!cookiesPath = config.get('COOKIES_PATH', currentRequest.sessionData.deviceId)
+      res.headers['Set-Cookie'] = "session=#{currentRequest.sessionData.sessionId}; Path=#{cookiesPath}"
+    else
+      res.headers['Set-Cookie'] = "session=#{currentRequest.sessionData.sessionId}"
 
-      writeResponse(currentRequest, res)
-    )
+    writeResponse(currentRequest, res)
   )
 
 
@@ -268,6 +266,8 @@ sendRpcRequest = (currentRequest, id, rpcRequest) ->
   if not rpcRequest?
     session.end(currentRequest.sessionData, (err, isNew) ->
       throw err if err
+
+      delete currentSessions.get(currentRequest.httpRequest.connection)[currentRequest.sessionData.sessionId]
       if isNew
         util.log("#{currentRequest.sessionData.deviceId}: New device registered")
 
@@ -293,10 +293,7 @@ sendRpcRequest = (currentRequest, id, rpcRequest) ->
     cwmpVersion : currentRequest.sessionData.cwmpVersion
   })
 
-  session.save(currentRequest.sessionData, (err) ->
-    throw err if err
-    writeResponse(currentRequest, res)
-  )
+  writeResponse(currentRequest, res)
 
 
 getSession = (httpRequest, callback) ->
@@ -307,9 +304,38 @@ getSession = (httpRequest, callback) ->
 
   return callback() if not sessionId?
 
-  session.load(sessionId, (err, sessionData) ->
-    throw err if err
-    return callback(sessionId, sessionData)
+  sessionData = currentSessions.get(httpRequest.connection)?[sessionId]
+
+  if sessionData?
+    return callback(null, sessionData)
+
+  setTimeout(() ->
+    db.redisClient.eval('local v=redis.call("get",KEYS[1]);redis.call("del",KEYS[1]);return v;', 1, "session_#{sessionId}", (err, sessionDataString) ->
+      return callback(err) if err or not sessionDataString
+      session.deserialize(sessionDataString, (err, sessionData) ->
+        return callback(err) if err
+        currentSessions.get(httpRequest.connection)[sessionId] = sessionData
+        callback(null, sessionData)
+      )
+    )
+  , 100
+  )
+
+
+currentSessions = new WeakMap()
+
+# When socket closes, store active sessions in redis
+onConnection = (socket) ->
+  currentSessions.set(socket, {})
+  socket.on('close', () ->
+    sessions = currentSessions.get(socket)
+    for sessionId, sessionData of sessions
+      session.serialize(sessionData, (err, sessionDataString) ->
+        throw err if err
+        db.redisClient.setex("session_#{sessionId}", sessionData.timeout, sessionDataString, (err) ->
+          throw err if err
+        )
+      )
   )
 
 
@@ -352,7 +378,8 @@ listener = (httpRequest, httpResponse) ->
 
   stream.on('end', () ->
     cwmpRequest = null
-    getSession(httpRequest, f = (sessionId, sessionData) ->
+    getSession(httpRequest, f = (err, sessionData) ->
+      throw err if err
       cwmpRequest ?= soap.request(httpRequest, sessionData?.cwmpVersion)
       if not sessionData?
         if cwmpRequest.methodRequest?.type isnt 'Inform'
@@ -364,6 +391,10 @@ listener = (httpRequest, httpResponse) ->
         return session.init(deviceId, cwmpRequest.cwmpVersion, cwmpRequest.sessionTimeout ? config.get('SESSION_TIMEOUT', deviceId), (err, sessionData) ->
           throw err if err
 
+          sessionData.sessionId = crypto.randomBytes(8).toString('hex')
+
+          currentSessions.get(httpRequest.connection)[sessionData.sessionId] = sessionData
+
           httpRequest.connection.setTimeout(sessionData.timeout * 1000)
 
           db.getDueTasksAndFaults(deviceId, sessionData.timestamp, (err, dueTasks, faults) ->
@@ -401,10 +432,7 @@ listener = (httpRequest, httpResponse) ->
             methodResponse : {type : 'GetRPCMethodsResponse', methodList : ['Inform', 'GetRPCMethods', 'TransferComplete', 'RequestDownload']},
             cwmpVersion : currentRequest.sessionData.cwmpVersion
           })
-          session.save(currentRequest.sessionData, (err) ->
-            throw err if err
-            writeResponse(currentRequest, res)
-          )
+          writeResponse(currentRequest, res)
         else if cwmpRequest.methodRequest.type is 'TransferComplete'
           throw new Error('ACS method not supported')
       else if cwmpRequest.methodResponse?
@@ -469,3 +497,4 @@ listener = (httpRequest, httpResponse) ->
 
 
 exports.listener = listener
+exports.onConnection = onConnection