feat: make sure session id is global unique (#170)

.travis.yml

@@ -3,5 +3,7 @@ language: node_js
 node_js:
   - '7'
   - '8'
+  - '10'
+  - '12'
 script: 'npm run test-travis'
 after_script: 'npm install coveralls@2 && cat ./coverage/lcov.info | coveralls'

Readme.md

@@ -113,7 +113,7 @@ console.log('listening on port 3000');
   Once you pass `options.store`, session storage is dependent on your external store -- you can't access the session if your external store is down. **Use external session stores only if necessary, avoid using session as a cache, keep the session lean, and store it in a cookie if possible!**
 
 
-  The way of generating external session id is controlled by the `options.genid`, which defaults to `Date.now() + '-' + uid.sync(24)`.
+  The way of generating external session id is controlled by the `options.genid`, which defaults to `uuid.v4()`.
 
   If you want to add prefix for all external session id, you can use `options.prefix`, it will not work if `options.genid` present.
 
@@ -127,7 +127,7 @@ console.log('listening on port 3000');
 - `session:invalid`: session value is invalid.
 - `session:expired`: session value is expired.
 
-### Custom External Key 
+### Custom External Key
 
 External key is used the cookie by default, but you can use `options.externalKey` to customize your own external key methods. `options.externalKey` with two methods:
 

index.js

@@ -4,7 +4,7 @@ const debug = require('debug')('koa-session');
 const ContextSession = require('./lib/context');
 const util = require('./lib/util');
 const assert = require('assert');
-const uid = require('uid-safe');
+const uuid = require('uuid/v4');
 const is = require('is-type-of');
 
 const CONTEXT_SESSION = Symbol('context#contextSession');
@@ -103,8 +103,8 @@ function formatOpts(opts) {
   }
 
   if (!opts.genid) {
-    if (opts.prefix) opts.genid = () => `${opts.prefix}${Date.now()}-${uid.sync(24)}`;
-    else opts.genid = () => `${Date.now()}-${uid.sync(24)}`;
+    if (opts.prefix) opts.genid = () => `${opts.prefix}${uuid()}`;
+    else opts.genid = uuid;
   }
 
   return opts;

package.json

@@ -14,6 +14,7 @@
     "lib"
   ],
   "devDependencies": {
+    "benchmark": "^2.1.4",
     "eslint": "3",
     "eslint-config-egg": "3",
     "istanbul": "0",
@@ -22,6 +23,7 @@
     "mocha": "^5.2.0",
     "mz-modules": "^2.0.0",
     "pedding": "^1.1.0",
+    "uid-safe": "^2.1.3",
     "should": "8",
     "supertest": "^3.3.0"
   },
@@ -30,7 +32,7 @@
     "crc": "^3.4.4",
     "debug": "^3.1.0",
     "is-type-of": "^1.0.0",
-    "uid-safe": "^2.1.3"
+    "uuid": "^3.3.2"
   },
   "engines": {
     "node": ">=7.6"

test/genid_bench.js

@@ -0,0 +1,45 @@
+'use strict';
+
+const Benchmark = require('benchmark');
+const uuid = require('uuid');
+const uid = require('uid-safe');
+
+const suite = new Benchmark.Suite();
+
+const genidByUid = () => `${Date.now()}-${uid.sync(24)}`;
+const genidByUuidV1 = () => uuid.v1();
+const genidByUuidV4 = () => uuid.v4();
+
+console.log('genidByUid() => %s', genidByUid());
+console.log('genidByUuidV1() => %s', genidByUuidV1());
+console.log('genidByUuidV4() => %s', genidByUuidV4());
+
+// add tests
+suite
+.add('uid()', function() {
+  genidByUid();
+})
+.add('genidByUuidV1()', function() {
+  genidByUuidV1();
+})
+.add('genidByUuidV4()', function() {
+  genidByUuidV4();
+})
+// add listeners
+.on('cycle', function(event) {
+  console.log(String(event.target));
+})
+.on('complete', function() {
+  console.log('Fastest is ' + this.filter('fastest').map('name'));
+})
+// run async
+.run({ async: true });
+
+// genidByUid() => 1556529339180-DRnQyEqlYjGr_Zq_42fHpdFMlBfVlAoG
+// genidByUuidV1() => 5af3b830-6a5f-11e9-91fb-abc918efca3d
+// genidByUuidV4() => 27088fa8-8436-4c8b-aae7-76ba316db9e3
+//
+// uid() x 260,850 ops/sec ±1.50% (84 runs sampled)
+// genidByUuidV1() x 1,181,483 ops/sec ±0.93% (86 runs sampled)
+// genidByUuidV4() x 301,840 ops/sec ±1.40% (83 runs sampled)
+// Fastest is genidByUuidV1()

test/store.test.js

@@ -448,7 +448,7 @@ describe('Koa Session External Store', () => {
         done = pedding(done, 2);
         const app = App({ maxAge: 100 });
         app.on('session:expired', args => {
-          assert(args.key.match(/^\d+-/));
+          assert(args.key.match(/^\w+-/));
           assert(args.value);
           assert(args.ctx);
           done();