Merge pull request #108 from segmentio/localstorage-fallback

feat(ids): check LocalStorage when cookies are not available

Author: f2prateek

lib/entity.js

@@ -106,10 +106,45 @@ Entity.prototype.id = function(id) {
  */
 
 Entity.prototype._getId = function() {
-  var ret = this._options.persist
-    ? this.storage().get(this._options.cookie.key)
-    : this._id;
-  return ret === undefined ? null : ret;
+  if (!this._options.persist) {
+    return this._id === undefined ? null : this._id;
+  }
+
+  // Check cookies.
+  var cookieId = this._getIdFromCookie();
+  if (cookieId) {
+    return cookieId;
+  }
+
+  // Check localStorage.
+  var lsId = this._getIdFromLocalStorage();
+  if (lsId) {
+    // Copy the id to cookies so we can read it directly from cookies next time.
+    this._setIdInCookies(lsId);
+    return lsId;
+  }
+
+  return null;
+};
+
+/**
+ * Get the entity's id from cookies.
+ *
+ * @return {String}
+ */
+
+Entity.prototype._getIdFromCookie = function() {
+  return this.storage().get(this._options.cookie.key);
+};
+
+/**
+ * Get the entity's id from cookies.
+ *
+ * @return {String}
+ */
+
+Entity.prototype._getIdFromLocalStorage = function() {
+  return store.get(this._options.cookie.key);
 };
 
 /**
@@ -120,12 +155,33 @@ Entity.prototype._getId = function() {
 
 Entity.prototype._setId = function(id) {
   if (this._options.persist) {
-    this.storage().set(this._options.cookie.key, id);
+    this._setIdInCookies(id);
+    this._setIdInLocalStorage(id);
   } else {
     this._id = id;
   }
 };
 
+/**
+ * Set the entity's `id` in cookies.
+ *
+ * @param {String} id
+ */
+
+Entity.prototype._setIdInCookies = function(id) {
+  this.storage().set(this._options.cookie.key, id);
+};
+
+/**
+ * Set the entity's `id` in local storage.
+ *
+ * @param {String} id
+ */
+
+Entity.prototype._setIdInLocalStorage = function(id) {
+  store.set(this._options.cookie.key, id);
+};
+
 /**
  * Get or set the entity's `traits`.
  *
@@ -201,8 +257,8 @@ Entity.prototype.identify = function(id, traits) {
 
 Entity.prototype.save = function() {
   if (!this._options.persist) return false;
-  cookie.set(this._options.cookie.key, this.id());
-  store.set(this._options.localStorage.key, this.traits());
+  this._setId(this.id());
+  this._setTraits(this.traits());
   return true;
 };
 
@@ -213,7 +269,8 @@ Entity.prototype.save = function() {
 Entity.prototype.logout = function() {
   this.id(null);
   this.traits({});
-  cookie.remove(this._options.cookie.key);
+  this.storage().remove(this._options.cookie.key);
+  store.remove(this._options.cookie.key);
   store.remove(this._options.localStorage.key);
 };
 
@@ -231,6 +288,6 @@ Entity.prototype.reset = function() {
  */
 
 Entity.prototype.load = function() {
-  this.id(cookie.get(this._options.cookie.key));
-  this.traits(store.get(this._options.localStorage.key));
+  this.id(this.id());
+  this.traits(this.traits());
 };

lib/user.js

@@ -11,6 +11,7 @@ var debug = require('debug')('analytics:user');
 var inherit = require('inherits');
 var rawCookie = require('component-cookie');
 var uuid = require('uuid');
+var localStorage = require('./store');
 
 /**
  * User defaults
@@ -99,12 +100,25 @@ User.prototype.anonymousId = function(anonymousId) {
   // set / remove
   if (arguments.length) {
     store.set('ajs_anonymous_id', anonymousId);
+    localStorage.set('ajs_anonymous_id', anonymousId);
     return this;
   }
 
   // new
   anonymousId = store.get('ajs_anonymous_id');
   if (anonymousId) {
+    // value exist in cookie, copy it to localStorage
+    localStorage.set('ajs_anonymous_id', anonymousId);
+    // refresh cookie to extend expiry
+    store.set('ajs_anonymous_id', anonymousId);
+    return anonymousId;
+  }
+
+  // if anonymousId doesn't exist in cookies, check localStorage
+  anonymousId = localStorage.get('ajs_anonymous_id');
+  if (anonymousId) {
+    // Write to cookies if available in localStorage but not cookies
+    store.set('ajs_anonymous_id', anonymousId);
     return anonymousId;
   }
 
@@ -113,13 +127,15 @@ User.prototype.anonymousId = function(anonymousId) {
   if (anonymousId) {
     anonymousId = anonymousId.split('----')[0];
     store.set('ajs_anonymous_id', anonymousId);
+    localStorage.set('ajs_anonymous_id', anonymousId);
     store.remove('_sio');
     return anonymousId;
   }
 
   // empty
   anonymousId = uuid.v4();
   store.set('ajs_anonymous_id', anonymousId);
+  localStorage.set('ajs_anonymous_id', anonymousId);
   return store.get('ajs_anonymous_id');
 };
 

test/group.test.js

@@ -39,6 +39,24 @@ describe('group', function() {
       assert(group.id() === 'gid');
       assert(group.traits().trait === true);
     });
+
+    it('id() should fallback to localStorage', function() {
+      var group = new Group();
+
+      group.id('gid');
+
+      // delete the cookie.
+      cookie.remove(cookieKey);
+
+      // verify cookie is deleted.
+      assert.equal(cookie.get(cookieKey), null);
+
+      // verify id() returns the id even when cookie is deleted.
+      assert.equal(group.id(), 'gid');
+
+      // verify cookie value is retored from localStorage.
+      assert.equal(cookie.get(cookieKey), 'gid');
+    });
   });
 
   describe('#id', function() {
@@ -226,6 +244,12 @@ describe('group', function() {
       assert(cookie.get(cookieKey) === 'id');
     });
 
+    it('should save an id to localStorage', function() {
+      group.id('id');
+      group.save();
+      assert(store.get(cookieKey) === 'id');
+    });
+
     it('should save properties to local storage', function() {
       group.properties({ property: true });
       group.save();
@@ -249,14 +273,21 @@ describe('group', function() {
       assert.deepEqual(group.properties(), {});
     });
 
-    it('should clear a cookie', function() {
+    it('should clear id in cookie', function() {
       group.id('id');
       group.save();
       group.logout();
       assert(cookie.get(cookieKey) === null);
     });
 
-    it('should clear local storage', function() {
+    it('should clear id in localStorage', function() {
+      group.id('id');
+      group.save();
+      group.logout();
+      assert(store.get(cookieKey) === undefined);
+    });
+
+    it('should clear traits in local storage', function() {
       group.properties({ property: true });
       group.save();
       group.logout();

test/user.test.js

@@ -43,6 +43,24 @@ describe('user', function() {
       assert(user.traits().trait === true);
     });
 
+    it('id() should fallback to localStorage', function() {
+      var user = new User();
+
+      user.id('id');
+
+      // delete the cookie.
+      cookie.remove(cookieKey);
+
+      // verify cookie is deleted.
+      assert.equal(cookie.get(cookieKey), null);
+
+      // verify id() returns the id even when cookie is deleted.
+      assert.equal(user.id(), 'id');
+
+      // verify cookie value is retored from localStorage.
+      assert.equal(cookie.get(cookieKey), 'id');
+    });
+
     it('should pick the old "_sio" anonymousId', function() {
       rawCookie('_sio', 'anonymous-id----user-id');
       var user = new User();
@@ -319,6 +337,45 @@ describe('user', function() {
         };
         assert(user.anonymousId() === undefined);
       });
+
+      it('should set anonymousId in both cookie and localStorage', function() {
+        var user = new User();
+        user.anonymousId('anon0');
+        assert.equal(cookie.get('ajs_anonymous_id'), 'anon0');
+        assert.equal(store.get('ajs_anonymous_id'), 'anon0');
+      });
+
+      it('should copy value from cookie to localStorage', function() {
+        var user = new User();
+        cookie.set('ajs_anonymous_id', 'anon1');
+        assert.equal(user.anonymousId(), 'anon1');
+        assert.equal(store.get('ajs_anonymous_id'), 'anon1');
+      });
+
+      it('should fall back to localStorage when cookie is not set', function() {
+        var user = new User();
+
+        user.anonymousId('anon12');
+        assert.equal(cookie.get('ajs_anonymous_id'), 'anon12');
+
+        // delete the cookie
+        cookie.remove('ajs_anonymous_id');
+        assert.equal(cookie.get('ajs_anonymous_id'), null);
+
+        // verify anonymousId() returns the correct id even when there's no cookie
+        assert.equal(user.anonymousId(), 'anon12');
+
+        // verify cookie value is retored from localStorage
+        assert.equal(cookie.get('ajs_anonymous_id'), 'anon12');
+      });
+
+      it('should write to both cookie and localStorage when generating a new anonymousId', function() {
+        var user = new User();
+        var anonId = user.anonymousId();
+        assert.notEqual(anonId, null);
+        assert.equal(cookie.get('ajs_anonymous_id'), anonId);
+        assert.equal(store.get('ajs_anonymous_id'), anonId);
+      });
     });
   });
 
@@ -400,6 +457,12 @@ describe('user', function() {
       assert(cookie.get(cookieKey) === 'id');
     });
 
+    it('should save an id to localStorage', function() {
+      user.id('id');
+      user.save();
+      assert.equal(store.get(cookieKey), 'id');
+    });
+
     it('should save traits to local storage', function() {
       user.traits({ trait: true });
       user.save();
@@ -425,14 +488,21 @@ describe('user', function() {
       assert(user.traits(), {});
     });
 
-    it('should clear a cookie', function() {
+    it('should clear id in cookie', function() {
       user.id('id');
       user.save();
       user.logout();
       assert(cookie.get(cookieKey) === null);
     });
 
-    it('should clear local storage', function() {
+    it('should clear id in local storage', function() {
+      user.id('id');
+      user.save();
+      user.logout();
+      assert(store.get(cookieKey) === undefined);
+    });
+
+    it('should clear traits in local storage', function() {
       user.traits({ trait: true });
       user.save();
       user.logout();