Added: cookieSession() only set-cookie on change. Clos senchalabs#442

lib/middleware/cookieParser.js

@@ -48,7 +48,9 @@ module.exports = function cookieParser(secret){
         req.cookies = utils.parseCookie(cookie);
         if (secret) {
           req.signedCookies = utils.parseSignedCookies(req.cookies, secret);
-          req.signedCookies = utils.parseJSONCookies(req.signedCookies);
+          var obj = utils.parseJSONCookies(req.signedCookies);
+          req.signedCookies = obj.cookies;
+          req.cookieHashes = obj.hashes;
         }
         req.cookies = utils.parseJSONCookies(req.cookies);
       } catch (err) {

lib/middleware/cookieSession.js

@@ -11,7 +11,8 @@
 
 var utils = require('./../utils')
   , Cookie = require('./session/cookie')
-  , debug = require('debug')('connect:cookieSession');
+  , debug = require('debug')('connect:cookieSession')
+  , crc16 = require('crc').crc16;
 
 // environment
 
@@ -69,12 +70,19 @@ module.exports = function cookieSession(options){
       // only send secure cookies via https
       if (cookie.secure && !secured) return debug('not secured');
 
-      // set cookie
+      // serialize
       debug('serializing %j', req.session);
       var val = 'j:' + JSON.stringify(req.session);
+
+      // compare hashes
+      var originalHash = req.cookieHashes && req.cookieHashes[key];
+      var hash = crc16(val);
+      if (originalHash == hash) return debug('unmodified session');
+
+      // set-cookie
       val = utils.sign(val, req.secret);
       val = utils.serializeCookie(key, val, cookie);
-      debug('cookie %j', cookie);
+      debug('set-cookie %j', cookie);
       res.setHeader('Set-Cookie', val);
     });
 

lib/utils.js

@@ -12,6 +12,7 @@
 
 var http = require('http')
   , crypto = require('crypto')
+  , crc16 = require('crc').crc16
   , Path = require('path')
   , fs = require('fs');
 
@@ -188,17 +189,24 @@ exports.parseSignedCookies = function(obj, secret){
  */
 
 exports.parseJSONCookies = function(obj){
+  var hashes = {};
+
   Object.keys(obj).forEach(function(key){
     var val = obj[key];
     if (0 == val.indexOf('j:')) {
       try {
+        hashes[key] = crc16(val); // only crc json cookies for now
         obj[key] = JSON.parse(val.slice(2));
       } catch (err) {
         // nothing
       }
     }
   });
-  return obj;
+
+  return {
+    cookies: obj,
+    hashes: hashes
+  };
 };
 
 /**

package.json

@@ -9,7 +9,12 @@
   "dependencies": {
     "qs": "0.4.2",
     "mime": "1.2.4",
+<<<<<<< HEAD
     "formidable": "1.0.9",
+=======
+    "formidable": "1.0.x",
+    "crc": "0.1.0",
+>>>>>>> crc-sessions
     "debug": "*"
   },
   "devDependencies": {

test/cookieSession.js

@@ -145,6 +145,77 @@ describe('connect.cookieSession()', function(){
     })
   })
 
+  describe('when modified', function(){
+    it('should set-cookie', function(done){
+      var n = 0;
+      var app = connect()
+        .use(connect.cookieParser('keyboard cat'))
+        .use(connect.cookieSession())
+        .use(function(req, res, next){
+          req.session.foo = ++n;
+          res.end();
+        });
+
+      app.request()
+      .get('/')
+      .end(function(res){
+        res.headers.should.have.property('set-cookie');
+
+        app.request()
+        .get('/')
+        .set('Cookie', sess(res))
+        .end(function(res){
+          res.headers.should.have.property('set-cookie');
+          done();
+        });
+      });
+    })
+  })
+
+  describe('when un-modified', function(){
+    it('should set-cookie only the initial time', function(done){
+      var modify;
+
+      var app = connect()
+        .use(connect.cookieParser('keyboard cat'))
+        .use(connect.cookieSession())
+        .use(function(req, res, next){
+          if (modify) req.session.foo = 'bar';
+          res.end();
+      });
+
+      app.request()
+      .get('/')
+      .end(function(res){
+        res.headers.should.have.property('set-cookie');
+        var cookie = sess(res);
+
+        app.request()
+        .get('/')
+        .set('Cookie', cookie)
+        .end(function(res){
+          res.headers.should.not.have.property('set-cookie');
+
+          app.request()
+          .get('/')
+          .set('Cookie', cookie)
+          .end(function(res){
+            res.headers.should.not.have.property('set-cookie');
+            modify = true;
+
+            app.request()
+            .get('/')
+            .set('Cookie', cookie)
+            .end(function(res){
+              res.headers.should.have.property('set-cookie');
+              done();
+            });
+          });
+        });
+      });
+    })
+  })
+
   describe('.secure', function(){
     it('should not set-cookie when insecure', function(done){
       var app = connect()