Update

Requirements:

1. First have redis running.
2. Next fire up socket.io.
3. Finally upload/host PHP(has dependencies in archive).

Socket.io

var express = require('express'),
        app         = express.createServer(),
        sio         = require('socket.io'),
        redis   = require("redis"),
    client  = redis.createClient(),
        io          = null;

/**
 *  Used to parse cookie
 */
function parse_cookies(_cookies) {
    var cookies = {};

    _cookies && _cookies.split(';').forEach(function( cookie ) {
        var parts = cookie.split('=');
        cookies[ parts[ 0 ].trim() ] = ( parts[ 1 ] || '' ).trim();
    });

    return cookies;
}

app.listen(3000, "localhost");
io = sio.listen(app);

io.of('/private').authorization(function (handshakeData, callback) {
        var cookies = parse_cookies(handshakeData.headers.cookie);

        client.get(cookies.PHPSESSID, function (err, reply) {
                handshakeData.identity = reply;
                callback(false, reply !== null);
        });
}).on('connection' , function (socket) {
        socket.emit('identity', socket.handshake.identity);
});

PHP

php with openid authentication 30 => http://dl.dropbox.com/u/314941/6503745/php.tar.gz

After login you have to reload client.php to 29 authenticate

p.s: I really don't like the concept of creating even another password which is probably is going to be unsafe. I would advice you to have a look at openID(via Google for example), Facebook Connect(just name a few options).

My question is once they authenticate via 28 php/session what would be the process 27 to authenticate the user to see if they 26 have the right login permissions to access 25 a nodejs server with socket.io? I dont 24 want the person to have access to the 23 nodejs/socket.io function/server unless 22 they have authenticated via the php login.

Add 21 the unique session_id to a list/set of allowed ids 20 so that socket.io can authorize(search for authorization 19 function) that connection. I would let PHP 18 communicate with node.js using redis because 17 that is going to be lightning fast/AWESOME 16 :). Right now I am faking the PHP communication 15 from redis-cli

Install Redis

Download redis => Right now the stable version 14 can be downloaded from: http://redis.googlecode.com/files/redis-2.2.11.tar.gz

alfred@alfred-laptop:~$ mkdir ~/6502031
alfred@alfred-laptop:~/6502031$ cd ~/6502031/
alfred@alfred-laptop:~/6502031$ tar xfz redis-2.2.11.tar.gz 
alfred@alfred-laptop:~/6502031$ cd redis-2.2.11/src
alfred@alfred-laptop:~/6502031/redis-2.2.11/src$ make # wait couple of seconds

Start Redis-server

alfred@alfred-laptop:~/6502031/redis-2.2.11/src$ ./redis-server 

Socket.io

npm dependencies

If npm is not already 13 installed , then first visit http://npmjs.org

npm install express
npm install socket.io
npm install redis

listing the 12 dependencies I have installed and which 11 you should also probably install in case 10 of incompatibility according to npm ls

alfred@alfred-laptop:~/node/socketio-demo$ npm ls
/home/alfred/node/socketio-demo
├─┬ express@2.3.12 
│ ├── connect@1.5.1 
│ ├── mime@1.2.2 
│ └── qs@0.1.0 
├── hiredis@0.1.12 
├── redis@0.6.0 
└─┬ socket.io@0.7.2 
  ├── policyfile@0.0.3 
  └── socket.io-client@0.7.2 

Code

server.js

var express = require('express'),
        app         = express.createServer(),
        sio         = require('socket.io'),
        redis   = require("redis"),
    client  = redis.createClient(),
        io          = null;

/**
 *  Used to parse cookie
 */
function parse_cookies(_cookies) {
    var cookies = {};

    _cookies && _cookies.split(';').forEach(function( cookie ) {
        var parts = cookie.split('=');
        cookies[ parts[ 0 ].trim() ] = ( parts[ 1 ] || '' ).trim();
    });

    return cookies;
}

app.listen(3000, "localhost");
io = sio.listen(app);

io.configure(function () {
  function auth (data, fn) {
    var cookies = parse_cookies(data.headers.cookie);
    console.log('PHPSESSID: ' + cookies.PHPSESSID);

        client.sismember('sid', cookies.PHPSESSID, function (err , reply) {
            fn(null, reply);    
        });
  };

  io.set('authorization', auth);
});

io.sockets.on('connection', function (socket) {
  socket.emit('access', 'granted');
});

To run server 9 just run node server.js

client.php

<?php

session_start();

echo "<h1>SID: " . session_id() . "</h1>";
?>
<html>
<head>
    <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.6.1/jquery.min.js"></script>
    <script src="http://localhost:3000/socket.io/socket.io.js"></script>
</head>
<body>
    <p id="text">access denied</p>
    <script>
        var socket = io.connect('http://localhost:3000/');
        socket.on('access', function (data) {
            $("#text").html(data);
        });
    </script>
</body>

Test authentication

When you load the webpage(PHP-file) from 8 your web-browser the message access denied is shown, but 7 when you add the session_id also shown in browser 6 to redis server the message access granted will be shown. Of 5 course normally you would not be doing any 4 copy pasting but just let PHP communicate 3 with Redis directly.. But for this demo 2 you will put SID ramom807vt1io3sqvmc8m4via1 into redis after which 1 access has been granted.

alfred@alfred-laptop:~/database/redis-2.2.0-rc4/src$ ./redis-cli 
redis> sadd sid ramom807vt1io3sqvmc8m4via1
(integer) 1
redis> 

Remember that sessions are just files stored 6 in the php sessions directory. It won't 5 be a problem for node.js to get the session 4 id from the cookie and then check if the 3 session really exists in the sessions directory. To 2 get the path of the sessions directory refer 1 to the session.save_path directive in your php.ini.

Here's the unserialize and utf8 code if 4 you want it too, originally derived from 3 phpjs.org - had to edit it a bit to make it work 2 with node.js so fish around and compare 1 if you want

function utf8_decode (str_data) {
    // http://kevin.vanzonneveld.net
    // +   original by: Webtoolkit.info (http://www.webtoolkit.info/)
    // +      input by: Aman Gupta
    // +   improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
    // +   improved by: Norman "zEh" Fuchs
    // +   bugfixed by: hitwork
    // +   bugfixed by: Onno Marsman
    // +      input by: Brett Zamir (http://brett-zamir.me)
    // +   bugfixed by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
    // *     example 1: utf8_decode('Kevin van Zonneveld');
    // *     returns 1: 'Kevin van Zonneveld'
    var tmp_arr = [],
        i = 0,
        ac = 0,
        c1 = 0,
        c2 = 0,
        c3 = 0;

    str_data += '';

    while (i < str_data.length) {
        c1 = str_data.charCodeAt(i);
        if (c1 < 128) {
            tmp_arr[ac++] = String.fromCharCode(c1);
            i++;
        } else if (c1 > 191 && c1 < 224) {
            c2 = str_data.charCodeAt(i + 1);
            tmp_arr[ac++] = String.fromCharCode(((c1 & 31) << 6) | (c2 & 63));
            i += 2;
        } else {
            c2 = str_data.charCodeAt(i + 1);
            c3 = str_data.charCodeAt(i + 2);
            tmp_arr[ac++] = String.fromCharCode(((c1 & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
            i += 3;
        }
    }

    return tmp_arr.join('');
}
exports.utf8_decode = utf8_decode;

function unserialize (data) {
    // http://kevin.vanzonneveld.net
    // +     original by: Arpad Ray (mailto:arpad@php.net)
    // +     improved by: Pedro Tainha (http://www.pedrotainha.com)
    // +     bugfixed by: dptr1988
    // +      revised by: d3x
    // +     improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
    // +        input by: Brett Zamir (http://brett-zamir.me)
    // +     improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
    // +     improved by: Chris
    // +     improved by: James
    // +        input by: Martin (http://www.erlenwiese.de/)
    // +     bugfixed by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
    // +     improved by: Le Torbi
    // +     input by: kilops
    // +     bugfixed by: Brett Zamir (http://brett-zamir.me)
    // -      depends on: utf8_decode
    // %            note: We feel the main purpose of this function should be to ease the transport of data between php & js
    // %            note: Aiming for PHP-compatibility, we have to translate objects to arrays
    // *       example 1: unserialize('a:3:{i:0;s:5:"Kevin";i:1;s:3:"van";i:2;s:9:"Zonneveld";}');
    // *       returns 1: ['Kevin', 'van', 'Zonneveld']
    // *       example 2: unserialize('a:3:{s:9:"firstName";s:5:"Kevin";s:7:"midName";s:3:"van";s:7:"surName";s:9:"Zonneveld";}');
    // *       returns 2: {firstName: 'Kevin', midName: 'van', surName: 'Zonneveld'}
    var that = this;
    var utf8Overhead = function (chr) {
        // http://phpjs.org/functions/unserialize:571#comment_95906
        var code = chr.charCodeAt(0);
        if (code < 0x0080) {
            return 0;
        }
        if (code < 0x0800) {
            return 1;
        }
        return 2;
    };


    var error = function (type, msg, filename, line) {
        console.log('[[[[[[[[[[[[[[[[[[ERROR]]]]]]]]]]]]]]]]]]]','msg:', msg, 'filename:',filename, 'line:',line);
    };
    var read_until = function (data, offset, stopchr) {
            if (stopchr == ';' && !data.match(/;$/)) data += ';';
        var buf = [];
        var chr = data.slice(offset, offset + 1);
        var i = 2;
        while (chr != stopchr) {
            if ((i + offset) > data.length) {
                error('Error', 'Invalid','php.js','126');
            }
            buf.push(chr);
            chr = data.slice(offset + (i - 1), offset + i);
            i += 1;
            //console.log('i:',i,'offset:',offset, 'data:',data,'chr:',chr,'stopchr:',stopchr);
        }
        return [buf.length, buf.join('')];
    };
    var read_chrs = function (data, offset, length) {
        var buf;

        buf = [];
        for (var i = 0; i < length; i++) {
            var chr = data.slice(offset + (i - 1), offset + i);
            buf.push(chr);
            length -= utf8Overhead(chr);
        }
        return [buf.length, buf.join('')];
    };
    var _unserialize = function (data, offset) {
        var readdata;
        var readData;
        var chrs = 0;
        var ccount;
        var stringlength;
        var keyandchrs;
        var keys;

        if (!offset) {
            offset = 0;
        }
        var dtype = (data.slice(offset, offset + 1)).toLowerCase();

        var dataoffset = offset + 2;
        var typeconvert = function (x) {
            return x;
        };

        switch (dtype) {
        case 'i':
            typeconvert = function (x) {
                return parseInt(x, 10);
            };
            readData = read_until(data, dataoffset, ';');
            chrs = readData[0];
            readdata = readData[1];
            dataoffset += chrs + 1;
            break;
        case 'b':
            typeconvert = function (x) {
                return parseInt(x, 10) !== 0;
            };
            readData = read_until(data, dataoffset, ';');
            chrs = readData[0];
            readdata = readData[1];
            dataoffset += chrs + 1;
            break;
        case 'd':
            typeconvert = function (x) {
                return parseFloat(x);
            };
            readData = read_until(data, dataoffset, ';');
            chrs = readData[0];
            readdata = readData[1];
            dataoffset += chrs + 1;
            break;
        case 'n':
            readdata = null;
            break;
        case 's':
            ccount = read_until(data, dataoffset, ':');
            chrs = ccount[0];
            stringlength = ccount[1];
            dataoffset += chrs + 2;

            readData = read_chrs(data, dataoffset + 1, parseInt(stringlength, 10));
            chrs = readData[0];
            readdata = readData[1];
            dataoffset += chrs + 2;
            if (chrs != parseInt(stringlength, 10) && chrs != readdata.length) {
                error('SyntaxError', 'String length mismatch','php.js','206');
            }

            // Length was calculated on an utf-8 encoded string
            // so wait with decoding
            readdata = utf8_decode(readdata);
            break;
        case 'a':
            readdata = {};

            keyandchrs = read_until(data, dataoffset, ':');
            chrs = keyandchrs[0];
            keys = keyandchrs[1];
            dataoffset += chrs + 2;

            for (var i = 0; i < parseInt(keys, 10); i++) {
                var kprops = _unserialize(data, dataoffset);
                var kchrs = kprops[1];
                var key = kprops[2];
                dataoffset += kchrs;

                var vprops = _unserialize(data, dataoffset);
                var vchrs = vprops[1];
                var value = vprops[2];
                dataoffset += vchrs;

                readdata[key] = value;
            }

            dataoffset += 1;
            break;
        default:
            error('SyntaxError', 'Unknown / Unhandled data type(s): ' + dtype,'php.js','238');
            break;
        }
        return [dtype, dataoffset - offset, typeconvert(readdata)];
    };

    return _unserialize((data + ''), 0)[2];
}
exports.unserialize = unserialize;

I was looking over the solutions here and 20 decided to give what rcode said a try because 19 it seemed so much easier than the gigantic 18 wall of code accepted answer.

It ended up 17 working nicely and is quite easy to do.

I 16 did end up installing a few dependencies 15 which I wanted to avoid but is relatively 14 easy to do with node.

Type the following 13 in console:

npm install cookie

npm install php-unserialize

This solution uses the session 12 files on the machine - you shouldn't have 11 to change this line.

session.save_handler = files

^ Should be like this 10 in your php.ini file (default).

(People suggested 9 using memcache, but it seemed like a headache 8 to switch over to that system.)

Here is the 7 super simple code to retrieve the session 6 data:

var cookie = require('cookie');
var fs = require('fs');
var phpUnserialize = require('php-unserialize');

//This should point to your php session directory.
//My php.ini says session.save_path = "${US_ROOTF}/tmp"
var SESS_PATH = "C:/SomeDirectory/WhereYourPHPIs/tmp/";

io.on('connection', function(socket) {
    //I just check if cookies are a string - may be better method
    if(typeof socket.handshake.headers.cookie === "string") {
        var sid = cookie.parse(socket.handshake.headers.cookie);
        if(typeof sid.PHPSESSID === "undefined") {
          console.log("Undefined PHPSESSID");
        }
        else {
            console.log("PHP Session ID: " + sid.PHPSESSID);
            fs.readFile(SESS_PATH + "sess_" + sid.PHPSESSID, 'utf-8', function(err,data) {
                if(!err) {
                    console.log("Session Data:");
                    var sd = phpUnserialize.unserializeSession(data);
                    console.log(sd);
                }
                else {
                   console.log(err);
                }
            });
        }
    }
}

Results:

Edit: I just wanted to add that it 5 may be easier to just have PHP tell your 4 Node.js server when someone logs in and 3 pass the credentials along there.

I explain 2 how to do this pretty easily in another 1 answer.

https://stackoverflow.com/a/49864533/1274820