Support for concurrent sessions

lib/connect-redis.js

@@ -10,6 +10,7 @@ module.exports = function (session) {
   // All callbacks should have a noop if none provided for compatibility
   // with the most Redis clients.
   const noop = () => {}
+  const TOMBSTONE = 'TOMBSTONE'
 
   class RedisStore extends Store {
     constructor(options = {}) {
@@ -27,12 +28,13 @@ module.exports = function (session) {
       this.disableTouch = options.disableTouch || false
     }
 
-    get(sid, cb = noop) {
+    get(sid, cb = noop, showTombs = false) {
       let key = this.prefix + sid
 
       this.client.get(key, (err, data) => {
         if (err) return cb(err)
         if (!data) return cb()
+        if (data === TOMBSTONE) return cb(null, showTombs ? data : undefined)
 
         let result
         try {
@@ -45,28 +47,40 @@ module.exports = function (session) {
     }
 
     set(sid, sess, cb = noop) {
-      let args = [this.prefix + sid]
-
-      let value
-      try {
-        value = this.serializer.stringify(sess)
-      } catch (er) {
-        return cb(er)
-      }
-      args.push(value)
+      this.get(
+        sid,
+        (err, oldSess) => {
+          if (oldSess === TOMBSTONE) {
+            return cb()
+          } else if (oldSess && oldSess.lastModified !== sess.lastModified) {
+            sess = mergeDeep(oldSess, sess)
+          }
+          let args = [this.prefix + sid]
+          let value
+          sess.lastModified = Date.now()
+          try {
+            value = this.serializer.stringify(sess)
+          } catch (er) {
+            return cb(er)
+          }
+          args.push(value)
+          args.push('EX', this._getTTL(sess))
 
-      let ttl = 1
-      if (!this.disableTTL) {
-        ttl = this._getTTL(sess)
-        args.push('EX', ttl)
-      }
+          let ttl = 1
+          if (!this.disableTTL) {
+            ttl = this._getTTL(sess)
+            args.push('EX', ttl)
+          }
 
-      if (ttl > 0) {
-        this.client.set(args, cb)
-      } else {
-        // If the resulting TTL is negative we can delete / destroy the key
-        this.destroy(sid, cb)
-      }
+          if (ttl > 0) {
+            this.client.set(args, cb)
+          } else {
+            // If the resulting TTL is negative we can delete / destroy the key
+            this.destroy(sid, cb)
+          }
+        },
+        true
+      )
     }
 
     touch(sid, sess, cb = noop) {
@@ -81,7 +95,9 @@ module.exports = function (session) {
 
     destroy(sid, cb = noop) {
       let key = this.prefix + sid
-      this.client.del(key, cb)
+      this.client.set([key, TOMBSTONE, 'EX', 300], (err) => {
+        cb(err, 1)
+      })
     }
 
     clear(cb = noop) {
@@ -92,9 +108,9 @@ module.exports = function (session) {
     }
 
     length(cb = noop) {
-      this._getAllKeys((err, keys) => {
+      this.all((err, result) => {
         if (err) return cb(err)
-        return cb(null, keys.length)
+        return cb(null, result.length)
       })
     }
 
@@ -121,7 +137,7 @@ module.exports = function (session) {
           let result
           try {
             result = sessions.reduce((accum, data, index) => {
-              if (!data) return accum
+              if (!data || data === TOMBSTONE) return accum
               data = this.serializer.parse(data)
               data.id = keys[index].substr(prefixLen)
               accum.push(data)
@@ -173,3 +189,35 @@ module.exports = function (session) {
 
   return RedisStore
 }
+
+/**
+ * Simple object check.
+ * @param item
+ * @returns {boolean}
+ */
+function isObject(item) {
+  return item && typeof item === 'object' && !Array.isArray(item)
+}
+
+/**
+ * Deep merge two objects.
+ * @param target
+ * @param ...sources
+ */
+function mergeDeep(target, ...sources) {
+  if (!sources.length) return target
+  const source = sources.shift()
+
+  if (isObject(target) && isObject(source)) {
+    for (const key in source) {
+      if (isObject(source[key])) {
+        if (!target[key]) Object.assign(target, { [key]: {} })
+        mergeDeep(target[key], source[key])
+      } else {
+        Object.assign(target, { [key]: source[key] })
+      }
+    }
+  }
+
+  return mergeDeep(target, ...sources)
+}

package.json

@@ -18,6 +18,7 @@
     "eslint-config-prettier": "^8.3.0",
     "express-session": "^1.17.0",
     "ioredis": "^4.17.1",
+    "mockdate": "^2.0.5",
     "nyc": "^15.0.1",
     "prettier": "^2.0.5",
     "redis": "^3.1.2",

test/connect-redis-test.js

@@ -4,8 +4,10 @@ const session = require('express-session')
 const redis = require('redis')
 const ioRedis = require('ioredis')
 const redisMock = require('redis-mock')
+const MockDate = require('mockdate')
 
 let RedisStore = require('../')(session)
+MockDate.set('2000-11-22')
 
 let p =
   (ctx, method) =>
@@ -58,11 +60,34 @@ test('redis-mock client', async (t) => {
 test('teardown', redisSrv.disconnect)
 
 async function lifecycleTest(store, t) {
-  let res = await p(store, 'set')('123', { foo: 'bar' })
+  await p(store, 'set')('123', { foo: 'bar3' })
+  let res = await p(store, 'get')('123')
+  t.same(res, { foo: 'bar3', lastModified: 974851200000 }, 'get value 1')
+  await p(store, 'set')('123', {
+    foo: 'bar3',
+    luke: 'skywalker',
+    obi: 'wan',
+    lastModified: 974851000000,
+  })
+  await p(store, 'set')('123', {
+    luke: 'skywalker',
+    lastModified: 974851000000,
+  })
+  res = await p(store, 'get')('123')
+  t.same(
+    res,
+    { foo: 'bar3', luke: 'skywalker', obi: 'wan', lastModified: 974851200000 },
+    'get merged value'
+  )
+
+  res = await p(store, 'clear')()
+  t.ok(res >= 1, 'cleared key')
+
+  res = await p(store, 'set')('123', { foo: 'bar' })
   t.equal(res, 'OK', 'set value')
 
   res = await p(store, 'get')('123')
-  t.same(res, { foo: 'bar' }, 'get value')
+  t.same(res, { foo: 'bar', lastModified: 974851200000 }, 'get value')
 
   res = await p(store.client, 'ttl')('sess:123')
   t.ok(res >= 86399, 'check one day ttl')
@@ -96,20 +121,29 @@ async function lifecycleTest(store, t) {
   t.same(
     res,
     [
-      { id: '123', foo: 'bar' },
-      { id: '456', cookie: { expires } },
+      { id: '123', foo: 'bar', lastModified: 974851200000 },
+      { id: '456', cookie: { expires }, lastModified: 974851200000 },
     ],
     'stored two keys data'
   )
 
   res = await p(store, 'destroy')('456')
   t.equal(res, 1, 'destroyed one')
 
+  res = await p(store, 'get')('456')
+  t.equal(res, undefined, 'tombstoned one')
+
+  res = await p(store, 'set')('456', { a: 'new hope' })
+  t.equal(res, undefined, 'tombstoned set')
+
+  res = await p(store, 'get')('456')
+  t.equal(res, undefined, 'tombstoned two')
+
   res = await p(store, 'length')()
   t.equal(res, 1, 'one key remains')
 
   res = await p(store, 'clear')()
-  t.equal(res, 1, 'cleared remaining key')
+  t.equal(res, 2, 'cleared remaining key')
 
   res = await p(store, 'length')()
   t.equal(res, 0, 'no key remains')