haste-server/node_modules/connect/lib/middleware/session.js

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2012-02-06 20:09:01 +01:00
/*!
* Connect - session
* Copyright(c) 2010 Sencha Inc.
* Copyright(c) 2011 TJ Holowaychuk
* MIT Licensed
*/
/**
* Module dependencies.
*/
var Session = require('./session/session')
, MemoryStore = require('./session/memory')
, Cookie = require('./session/cookie')
, Store = require('./session/store')
, utils = require('./../utils')
, parse = require('url').parse
, crypto = require('crypto');
// environment
var env = process.env.NODE_ENV;
/**
* Expose the middleware.
*/
exports = module.exports = session;
/**
* Expose constructors.
*/
exports.Store = Store;
exports.Cookie = Cookie;
exports.Session = Session;
exports.MemoryStore = MemoryStore;
/**
* Warning message for `MemoryStore` usage in production.
*/
var warning = 'Warning: connection.session() MemoryStore is not\n'
+ 'designed for a production environment, as it will leak\n'
+ 'memory, and obviously only work within a single process.';
/**
* Default finger-printing function.
*/
function defaultFingerprint(req) {
var ua = req.headers['user-agent'] || '';
return ua.replace(/;?\schromeframe\/[\d\.]+/, '');
};
/**
* Paths to ignore.
*/
exports.ignore = [];
/**
* Setup session store with the given `options`.
*
* Session data is _not_ saved in the cookie itself, however
* cookies are used, so we must use the [cookieParser()](middleware-cookieParser.html)
* middleware _before_ `session()`.
*
* Examples:
*
* connect.createServer(
* connect.cookieParser()
* , connect.session({ secret: 'keyboard cat' })
* );
*
* Options:
*
* - `key` cookie name defaulting to `connect.sid`
* - `store` Session store instance
* - `fingerprint` Custom fingerprint generating function
* - `cookie` Session cookie settings, defaulting to `{ path: '/', httpOnly: true, maxAge: 14400000 }`
* - `secret` Secret string used to compute hash
*
* Ignore Paths:
*
* By default `/favicon.ico` is the only ignored path, all others
* will utilize sessions, to manipulate the paths ignored, use
* `connect.session.ignore.push('/my/path')`. This works for _full_
* pathnames only, not segments nor substrings.
*
* connect.session.ignore.push('/robots.txt');
*
* ## req.session
*
* To store or access session data, simply use the request property `req.session`,
* which is (generally) serialized as JSON by the store, so nested objects
* are typically fine. For example below is a user-specific view counter:
*
* connect(
* connect.cookieParser()
* , connect.session({ secret: 'keyboard cat', cookie: { maxAge: 60000 }})
* , connect.favicon()
* , function(req, res, next){
* var sess = req.session;
* if (sess.views) {
* res.setHeader('Content-Type', 'text/html');
* res.write('<p>views: ' + sess.views + '</p>');
* res.write('<p>expires in: ' + (sess.cookie.maxAge / 1000) + 's</p>');
* res.end();
* sess.views++;
* } else {
* sess.views = 1;
* res.end('welcome to the session demo. refresh!');
* }
* }
* ).listen(3000);
*
* ## Session#regenerate()
*
* To regenerate the session simply invoke the method, once complete
* a new SID and `Session` instance will be initialized at `req.session`.
*
* req.session.regenerate(function(err){
* // will have a new session here
* });
*
* ## Session#destroy()
*
* Destroys the session, removing `req.session`, will be re-generated next request.
*
* req.session.destroy(function(err){
* // cannot access session here
* });
*
* ## Session#reload()
*
* Reloads the session data.
*
* req.session.reload(function(err){
* // session updated
* });
*
* ## Session#save()
*
* Save the session.
*
* req.session.save(function(err){
* // session saved
* });
*
* ## Session#touch()
*
* Updates the `.maxAge`, and `.lastAccess` properties. Typically this is
* not necessary to call, as the session middleware does this for you.
*
* ## Session#cookie
*
* Each session has a unique cookie object accompany it. This allows
* you to alter the session cookie per visitor. For example we can
* set `req.session.cookie.expires` to `false` to enable the cookie
* to remain for only the duration of the user-agent.
*
* ## Session#maxAge
*
* Alternatively `req.session.cookie.maxAge` will return the time
* remaining in milliseconds, which we may also re-assign a new value
* to adjust the `.expires` property appropriately. The following
* are essentially equivalent
*
* var hour = 3600000;
* req.session.cookie.expires = new Date(Date.now() + hour);
* req.session.cookie.maxAge = hour;
*
* For example when `maxAge` is set to `60000` (one minute), and 30 seconds
* has elapsed it will return `30000` until the current request has completed,
* at which time `req.session.touch()` is called to update `req.session.lastAccess`,
* and reset `req.session.maxAge` to its original value.
*
* req.session.cookie.maxAge;
* // => 30000
*
* Session Store Implementation:
*
* Every session store _must_ implement the following methods
*
* - `.get(sid, callback)`
* - `.set(sid, session, callback)`
* - `.destroy(sid, callback)`
*
* Recommended methods include, but are not limited to:
*
* - `.length(callback)`
* - `.clear(callback)`
*
* For an example implementation view the [connect-redis](http://github.com/visionmedia/connect-redis) repo.
*
* @param {Object} options
* @return {Function}
* @api public
*/
function session(options){
var options = options || {}
, key = options.key || 'connect.sid'
, secret = options.secret
, store = options.store || new MemoryStore
, fingerprint = options.fingerprint || defaultFingerprint
, cookie = options.cookie;
// notify user that this store is not
// meant for a production environment
if ('production' == env && store instanceof MemoryStore) {
console.warn(warning);
}
// ensure secret is present
if (!secret) {
throw new Error('connect.session({ secret: "string" }) required for security');
}
// session hashing function
store.hash = function(req, base) {
return crypto
.createHmac('sha256', secret)
.update(base + fingerprint(req))
.digest('base64')
.replace(/=*$/, '');
};
// generates the new session
store.generate = function(req){
var base = utils.uid(24);
var sessionID = base + '.' + store.hash(req, base);
req.sessionID = sessionID;
req.session = new Session(req);
req.session.cookie = new Cookie(cookie);
};
return function session(req, res, next) {
// self-awareness
if (req.session) return next();
// parse url
var url = parse(req.url)
, path = url.pathname;
// ignorable paths
if (~exports.ignore.indexOf(path)) return next();
// expose store
req.sessionStore = store;
// proxy writeHead() to Set-Cookie
var writeHead = res.writeHead;
res.writeHead = function(status, headers){
if (req.session) {
var cookie = req.session.cookie;
// only send secure session cookies when there is a secure connection.
// proxySecure is a custom attribute to allow for a reverse proxy
// to handle SSL connections and to communicate to connect over HTTP that
// the incoming connection is secure.
var secured = cookie.secure && (req.connection.encrypted || req.connection.proxySecure);
if (secured || !cookie.secure) {
res.setHeader('Set-Cookie', cookie.serialize(key, req.sessionID));
}
}
res.writeHead = writeHead;
return res.writeHead(status, headers);
};
// proxy end() to commit the session
var end = res.end;
res.end = function(data, encoding){
res.end = end;
if (req.session) {
// HACK: ensure Set-Cookie for implicit writeHead()
if (!res._header) res._implicitHeader();
req.session.resetMaxAge();
req.session.save(function(){
res.end(data, encoding);
});
} else {
res.end(data, encoding);
}
};
// session hashing
function hash(base) {
return store.hash(req, base);
}
// generate the session
function generate() {
store.generate(req);
}
// get the sessionID from the cookie
req.sessionID = req.cookies[key];
// make a new session if the browser doesn't send a sessionID
if (!req.sessionID) {
generate();
next();
return;
}
// check the fingerprint
var parts = req.sessionID.split('.');
if (parts[1] != hash(parts[0])) {
generate();
next();
return;
}
// generate the session object
var pause = utils.pause(req);
store.get(req.sessionID, function(err, sess){
// proxy to resume() events
var _next = next;
next = function(err){
_next(err);
pause.resume();
}
// error handling
if (err) {
if ('ENOENT' == err.code) {
generate();
next();
} else {
next(err);
}
// no session
} else if (!sess) {
generate();
next();
// populate req.session
} else {
store.createSession(req, sess);
next();
}
});
};
};