socket.io with access to Connect/Express session
This simple and micro node_module was born from my needs to get read/write to the fresh session, used in a express (3.0)/connect node web application, in the socket.io events.
I tested with connect 2.7.3, express 3.1.0 and socket.io 0.9.13, but this it is a beta release becasuse I didn't execute any test framework and in the present time, it is used in the private beta release of iWaz.at (http://www.iwaz.at).
$ npm install expression.socket.io
Write the boilerplate Express App and socket.io connection, bearing in mind to keep a reference to the used Connect cookie parser and session store.
var http = require'http';var express = require'express';var app = express;var httpSrv = httpcreateServerexpressApp;/** Configure the express app with middleware that your app needs in the correct order, in this example I have only put the two middlewares that the expression.socket.io needs **/var connect = require'connect';var cookieParser = expresscookieParser'my session secret';var sessionStore = sessionMemoryStore;appusecookieParser;appuseexpresssessionstore: sessionStorecookie :path : '/'httpOnly : truemaxAge : null;
Then setup the expression.socket.io and write your events
var io = require'socket.io';var expressionSocketIo = require'expression.socket.io';expressionSocketIoio sessionStore cookieParser;// In this line our socket.io is ready to get the session as parameter in authentication callback// and event listeners registered with the new available sessOn methodiosocketssessOn'connection'socketsessOn'client says'if errconsole.logerr;return;if !sessionconsole.log'The session has not been got';else//Here you can access to the session from the session argument received in this callbacksocketemit'response' 'REPLY SOCKET FROM EXPRESSION.SOCKET.IO';;;
The expression.socket.io is just a function that wrap the original 'authorization' socket.io method to provide to the callback received like parameter with the fresh express user's session, besides the usual error paremeter of the node convention callbacks.
It also attaches to the socket a new one method 'sessOn', to register event listeners which we need access to user's session to perform some action tha our uses cases require.
This two commented tweaks apply in the same way for the namespaced sockets, so socket.io#of method returns a socket with those tweaks, unless 'true' value has been passed as second parameter, the first one is the namespace id required by the original socket.io#of method.
In all the rest, socket.io is the same as if expression.socket.io hadn't been applied.
Expression.socket.io receives four parameters, the first three are required, the last one is an object of options and each option no specified, a default value is used.
The functions returns the socket.io object received like first parameter, to allow the chaining.
var options =key: 'mysessionname.sess'autoErrManager: truenoSessIo: true;var expressionSocketIo = require'expression.socket.io';var expressionIo = expressionSocketIoio sessionStore cookieParser options;
The callbacks receive one or two parameters more than the original callbacks that socket.io requests; if the autoErrManager has not been provided or false was specified, then the first parameter is an error object provided by cookie parser or session store or null if there wasn't any error or there was one but they didn't provide an error object, in that case the second parameter, the session, it will be null or undefined.
If the autoErrManager was true, then the callback will be called if the session has been got and it will be provided to the callback as the first parameter, the following parameters are the parameters of the original socket.io's methods.
The 'authorization' method is used to check the data provided by the client in the handshake process and to evalute if the client is authorized or not connection (https://github.com/LearnBoost/socket.io/wiki/Authorizing).
iosocketsauthorization// This is an example, sure that you would like to check some stored values in the sessionif err || !sessionfnerr false;elsefnerr true;;
'onSess' method is used as the original 'on' method with the difference that the callback receive the session like parameter.
iosocketssessOn'connection'socketsessOn'client says'if errconsole.logerr;return;if !sessionconsole.log'The session has not been got';else//Here you can access to the session from the session argument received in this callbacksocketemit'response' 'REPLY SOCKET FROM EXPRESSION.SOCKET.IO';;;
The clients' socket as the server's socket has the 'sessOn', which receive two parameters more at the beginning followed by the socket.io's original parameters, so one or two depending if the client emitter expects and acknowledgement.
NOTE: That if you change the session data, then you will need to call the session#save method to persist the new changes. Also, bear in mind that the access to the session has a performance impact, so if you don't need to access to the session in some events, then use the original 'on' method.
iosocketson'connection'socketsessOn'get session data'if err console.logerr;if !sessionconsole.log'The session has not been got';elseconsole.log'The message recevied is: ' + data;ackFn'Server acknowledge';// Example, it would be need to check if the session has the user object and its name.socketemit'response' 'server replies (socket 1) - user name:' + sessionusername;sessionsocket: 'I am the socket 1';sessionsave;;socketon'no session'ackFn'No session acknowledge - SOCKET';socketemit'response' 'REPLY SOCKET from no session event';;;
The session socket is the same socket.io instance object returned by socket.io#listen, so all the functionalities plus the session features are available on it. The order release was a wrapper object, so some features, like use session in rooms weren't possible.
The module is just a function, rather than a Constructor.
I would like to appreciate to the people who wrote in some blogs how to grant to socket.io the access to the Connect/Express session, between others, Daniel Baulig (http://www.danielbaulig.de/socket-ioexpress/) and Robert Martin (http://notjustburritos.tumblr.com/post/22682186189/socket-io-and-express-3); and also to Wagner Camarao (https://github.com/functioncallback/session.socket.io) and Peter Klaesson (https://github.com/alphapeter/socket.io-express) for providing some modules in the same scope with it.
But it there are two modules which does it, why did I build it? Well, I have developed it, because I needed to access to the Express session but not only in the state that it is, when the client connects, but also when the client sends some messages, and as I couldn't get the fresh session with the modules that I found.
License (The MIT License)
Copyright (c) 2013 Ivan Fraixedes Cugat email@example.com
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