feat: support rolling (#82)

* feat: support rolling

* f

* feat: pass options to store

Readme.md

@@ -54,7 +54,9 @@ var CONFIG = {
   overwrite: true, /** (boolean) can overwrite or not (default true) */
   httpOnly: true, /** (boolean) httpOnly or not (default true) */
   signed: true, /** (boolean) signed or not (default true) */
+  rolling: false, /** (boolean) Force a session identifier cookie to be set on every response. The expiration is reset to the original maxAge, resetting the expiration countdown. default is false **/
 };
+
 app.use(session(CONFIG, app));
 // or if you prefer all default config, just use => app.use(session(app));
 
@@ -111,8 +113,8 @@ app.use(convert(session(app)));
 
   You can store the session content in external stores(redis, mongodb or other DBs) by pass `options.store` with three methods(need to be generator function or async function):
 
-  - `get(key)`: get session object by key
-  - `set(key, sess, maxAge)`: set session object for key, with a `maxAge` (in ms)
+  - `get(key, maxAge, { rolling })`: get session object by key
+  - `set(key, sess, maxAge, { rolling, changed })`: set session object for key, with a `maxAge` (in ms)
   - `destroy(key)`: destroy session for key
 
 

lib/context.js

@@ -79,7 +79,7 @@ class ContextSession {
       return;
     }
 
-    const json = yield this.store.get(externalKey);
+    const json = yield this.store.get(externalKey, opts.maxAge, { rolling: opts.rolling });
     if (!this.valid(json)) {
       // create a new `externalKey`
       this.create();
@@ -203,19 +203,21 @@ class ContextSession {
     }
 
     // force save session when `session._requireSave` set
+    let changed = true;
     if (!session._requireSave) {
       const json = session.toJSON();
       // do nothing if new and not populated
       if (!prevHash && !Object.keys(json).length) return;
-      // do nothing if not changed
-      if (prevHash === util.hash(json)) return;
+      changed = prevHash !== util.hash(json);
+      // do nothing if not changed and not in rolling mode
+      if (!this.opts.rolling && !changed) return;
     }
 
     if (typeof opts.beforeSave === 'function') {
       debug('before save');
       opts.beforeSave(ctx, session);
     }
-    yield this.save();
+    yield this.save(changed);
   }
 
   /**
@@ -238,7 +240,7 @@ class ContextSession {
    * @api private
    */
 
-  * save() {
+  * save(changed) {
     const opts = this.opts;
     const key = opts.key;
     const externalKey = this.externalKey;
@@ -258,7 +260,10 @@ class ContextSession {
     // save to external store
     if (externalKey) {
       debug('save %j to external key %s', json, externalKey);
-      yield this.store.set(externalKey, json, maxAge);
+      yield this.store.set(externalKey, json, maxAge, {
+        changed,
+        rolling: opts.rolling,
+      });
       this.ctx.cookies.set(key, externalKey, opts);
       return;
     }

test/cookie.test.js

@@ -755,6 +755,46 @@ describe('Koa Session Cookie', () => {
       });
     });
   });
+
+  describe('when rolling set to true', () => {
+    let app;
+    before(() => {
+      app = App({ rolling: true });
+
+      app.use(function* () {
+        console.log(this.path);
+        if (this.path === '/set') this.session = { foo: 'bar' };
+        this.body = this.session;
+      });
+    });
+
+    it('should not send set-cookie when session not exists', () => {
+      return request(app.callback())
+      .get('/')
+      .expect({})
+      .expect(res => {
+        should.not.exist(res.headers['set-cookie']);
+      });
+    });
+
+    it('should send set-cookie when session exists and not change', done => {
+      request(app.callback())
+      .get('/set')
+      .expect({ foo: 'bar' })
+      .end((err, res) => {
+        should.not.exist(err);
+        res.headers['set-cookie'].should.have.length(2);
+        const cookie = res.headers['set-cookie'].join(';');
+        request(app.callback())
+        .get('/')
+        .set('cookie', cookie)
+        .expect(res => {
+          res.headers['set-cookie'].should.have.length(2);
+        })
+        .expect({ foo: 'bar' }, done);
+      });
+    });
+  });
 });
 
 function App(options) {

test/store.test.js

@@ -628,6 +628,44 @@ describe('Koa Session External Store', () => {
     });
   });
 
+  describe('when rolling set to true', () => {
+    let app;
+    before(() => {
+      app = App({ rolling: true });
+
+      app.use(function* () {
+        if (this.path === '/set') this.session = { foo: 'bar' };
+        this.body = this.session;
+      });
+    });
+
+    it('should not send set-cookie when session not exists', () => {
+      return request(app.callback())
+      .get('/')
+      .expect({})
+      .expect(res => {
+        should.not.exist(res.headers['set-cookie']);
+      });
+    });
+
+    it('should send set-cookie when session exists and not change', done => {
+      request(app.callback())
+      .get('/set')
+      .expect({ foo: 'bar' })
+      .end((err, res) => {
+        should.not.exist(err);
+        res.headers['set-cookie'].should.have.length(2);
+        const cookie = res.headers['set-cookie'].join(';');
+        request(app.callback())
+        .get('/')
+        .set('cookie', cookie)
+        .expect(res => {
+          res.headers['set-cookie'].should.have.length(2);
+        })
+        .expect({ foo: 'bar' }, done);
+      });
+    });
+  });
 });
 
 function App(options) {