From a2f622091f834825b9e96553581e606051d3e0a3 Mon Sep 17 00:00:00 2001
From: Simon Scherzinger <scherzinger@entrecode.de>
Date: Tue, 23 Feb 2016 17:31:04 +0100
Subject: [PATCH] somewhat the first version of cached data.

---
 lib/DataManager.js |  27 +++++++---
 lib/Model.js       |  68 +++++++++++++++++++------
 test/sdk.test.js   | 120 ++++++++++++++++++++++++++++++++++-----------
 3 files changed, 165 insertions(+), 50 deletions(-)

diff --git a/lib/DataManager.js b/lib/DataManager.js
index 3817269..87fa088 100644
--- a/lib/DataManager.js
+++ b/lib/DataManager.js
@@ -674,14 +674,14 @@ DataManager.prototype._requestOptions = function(additionalHeaders) {
 };
 
 DataManager.prototype._makeDB = function() {
+  if (this._db) {
+    return Promise.resolve(this._db);
+  }
+  this._db = new loki(this.id + '.db.json', {
+    autosave: true,
+    autosaveInterval: 30000
+  });
   return new Promise(function(resolve, reject) {
-    if (this._db) {
-      return resolve(this._db);
-    }
-    this._db = new loki(this.id + '.db.json', {
-      autosave: true,
-      autosaveInterval: 30000
-    });
     this._db.loadDatabase({}, function(err) {
       if (err && err.message.indexOf('ENOENT') !== -1) {
         return this._db.saveDatabase(function(err) {
@@ -696,6 +696,19 @@ DataManager.prototype._makeDB = function() {
       }
       return resolve(this._db);
     }.bind(this));
+  }.bind(this))
+  .then(function(db) {
+    this._cacheMetaData = db.getCollection('_metadata');
+    if (!this._cacheMetaData) {
+      this._cacheMetaData = db.addCollection('_metadata', {
+        indices: [
+          'etag',
+          'created',
+          'title'
+        ]
+      });
+    }
+    return Promise.resolve(db);
   }.bind(this));
 };
 
diff --git a/lib/Model.js b/lib/Model.js
index 7bbc40e..de51178 100644
--- a/lib/Model.js
+++ b/lib/Model.js
@@ -18,43 +18,49 @@ var Model = function(title, metadata, dm) {
 
 Model.prototype.enableCache = function(maxCacheAge) {
   return this._dm._makeDB().then(function(db) {
-    this._collection = db.getCollection(this.title);
-    if (!this._collection) {
-      this._collection = db.addCollection(this.title, {
+    this._maxAge = maxCacheAge || 600000;
+    this._items = db.getCollection(this.title) || db.addCollection(this.title, {
         indices: [
           '_id',
           '_entryTitle'
         ]
       });
-    }
+    //this._items.ensureUniqueIndex('_id');
     return this._loadData();
-  }.bind(this)).catch(function(err) {
-    throw err;
-  });
+  }.bind(this));
 };
 
 Model.prototype._loadData = function() {
-  return new Promise(function(resolve, reject) {
-    this._getTraversal().then(function(traversal) {
+  return this._getTraversal()
+  .then(function(traversal) {
+    return new Promise(function(resolve, reject) {
       traversal.continue().newRequest()
       .follow(this._dm.id + ':' + this.title)
       .withRequestOptions(this._dm._requestOptions())
       .withTemplateParameters({ size: 0 })
       .get(function(err, res, traversal) {
-        util.checkResponse(err, res).then(function(res) {
+        return util.checkResponse(err, res)
+        .then(function(res) {
           var body = halfred.parse(JSON.parse(res.body));
           var entries = body.embeddedResourceArray(this._dm.id + ':' + this.title);
-          this._collection.removeDataOnly();
+          this._items.removeDataOnly();
           for (var i = 0; i < entries.length; i++) {
-            this._collection.insert(entries[i]);
+            this._items.insert(entries[i].original());
           }
+          this._dm._cacheMetaData.removeWhere({ title: this.title });
+          this._dm._cacheMetaData.insert({
+            title: this.title,
+            etag: res.headers.etag,
+            created: new Date().toISOString()
+          });
           this._dm._db.save(function(err) {
             if (err) {
               return reject(err);
             }
-            return resolve(this);
-          }.bind(this))
-        }.bind(this)).catch(reject);
+            return resolve(this._items);
+          }.bind(this));
+        }.bind(this))
+        .catch(reject);
       }.bind(this));
     }.bind(this));
   }.bind(this));
@@ -88,6 +94,15 @@ Model.prototype._getTraversal = function() {
   });
 };
 
+Model.prototype._ensureNotStale = function() {
+  var maxAge = new Date().getTime() - this._maxAge;
+  var created = new Date(this._dm._cacheMetaData.find({ title: this.title })[0].created).getTime();
+  if (created > maxAge) {
+    return Promise.resolve(this._items);
+  }
+  return this._loadData();
+};
+
 Model.prototype.resolve = function() {
   var model = this;
   return new Promise(function(resolve, reject) {
@@ -132,6 +147,29 @@ Model.prototype.getSchema = function(method) {
 
 Model.prototype.entryList = function(options) {
   var model = this;
+  if (this._maxAge) {
+    return Promise.resolve()
+    .then(function() {
+      switch (options.cacheType || 'default') {
+      case 'stale':
+        throw new Error('cacheType \'stale\' not implemented.');
+      case 'refresh':
+        return this._loadData();
+      case 'default':
+      default:
+        return this._ensureNotStale();
+      }
+    }.bind(this))
+    .then(function(items) {
+      var res = items.find('getAll');
+      var out = [];
+      for (var i = 0; i < res.length; i++) {
+        out.push(new Entry(halfred.parse(res[i]), this._dm, this));
+      }
+      return Promise.resolve({ entries: out, count: out.length, total: items.data.length })
+    }.bind(this));
+  }
+
   return this._getTraversal().then(function(traversal) {
     return new Promise(function(resolve, reject) {
       var t = traversal.continue().newRequest()
diff --git a/test/sdk.test.js b/test/sdk.test.js
index fdfae01..f7a316a 100644
--- a/test/sdk.test.js
+++ b/test/sdk.test.js
@@ -468,40 +468,104 @@ describe('model', function() {
   });
 });
 
-describe('offline model', function() {
-  var dm;
-  beforeEach(function() {
-    dm = new DataManager({
-      url: baseUrl + '58b9a1f5'
+if (isNode) {
+  describe('offline model', function() {
+    var dm;
+    beforeEach(function() {
+      dm = new DataManager({
+        url: baseUrl + '58b9a1f5'
+      });
     });
-  });
-  afterEach(function() {
-    dm = null;
-  });
-  it('make single model offline by dm', function() {
-    return dm.enableCache('to-do-list').then(function(models) {
-      expect(models[0]).to.be.a('object');
-      expect(models[0].id).to.be.equal('to-do-list');
-      expect(models[0]._collection).to.be.a('object');
+    afterEach(function() {
+      dm = null;
+    });
+    it('make single model offline by dm', function() {
+      return dm.enableCache('to-do-list').then(function(models) {
+        expect(dm._cacheMetaData).to.be.a('object');
+        expect(models[0]).to.be.a('object');
+        expect(models[0].name).to.be.equal('to-do-list');
+      });
+    });
+    it('make single model offline by model', function() {
+      return dm.model('to-do-list').enableCache().then(function(model) {
+        expect(dm._cacheMetaData).to.be.a('object');
+        expect(model).to.be.a('object');
+        expect(model.name).to.be.equal('to-do-list');
+      });
+    });
+    it('make multiple models offline by dm', function() {
+      return dm.enableCache([
+        'to-do-list',
+        'to-do-item'
+      ]).then(function(models) {
+        expect(models).to.be.a('array');
+        expect(models.length).to.be.equal(2);
+      }).catch();
     });
   });
-  it('make single model offline by model', function() {
-    return dm.model('to-do-list').enableCache().then(function(model) {
-      expect(model).to.be.a('object');
-      expect(model.id).to.be.equal('to-do-list');
-      expect(model._collection).to.be.a('object');
+  describe('stale data', function() {
+    var dm;
+    beforeEach(function(done) {
+      dm = new DataManager({
+        url: baseUrl + '58b9a1f5'
+      });
+      dm.enableCache([
+        'to-do-item',
+        'to-do-list'
+      ], 1)
+      .then(function() {
+        done();
+      })
+      .catch(done);
+    });
+    afterEach(function() {
+      dm = null;
+    });
+    it('entries size 0', function() {
+      return dm.model('to-do-list').entries({ size: 0 })
+      .then(function(entries) {
+        expect(entries.length).to.be.equal(2);
+      });
     });
   });
-  it('make multiple models offline by dm', function() {
-    return dm.enableCache([
-      'to-do-list',
-      'to-do-item'
-    ]).then(function(models) {
-      expect(models).to.be.a('array');
-      expect(models.length).to.be.equal(2);
-    }).catch();
+  describe('valid cache data', function() {
+    var dm;
+    beforeEach(function(done) {
+      dm = new DataManager({
+        url: baseUrl + '58b9a1f5'
+      });
+      dm.enableCache([
+        'to-do-item',
+        'to-do-list'
+      ])
+      .then(function() {
+        done();
+      })
+      .catch(done);
+    });
+    afterEach(function() {
+      dm = null;
+    });
+    it('entries size 0', function() {
+      return dm.model('to-do-list').entries({ size: 0 })
+      .then(function(entries) {
+        expect(entries.length).to.be.equal(2);
+      });
+    });
+    it('entries size 0', function() {
+      return dm.model('to-do-list').entries({ size: 0, cacheType: 'refresh' })
+      .then(function(entries) {
+        expect(entries.length).to.be.equal(2);
+      });
+    });
+    it.skip('entries size 0', function() {
+      return dm.model('to-do-list').entries({ size: 0, cacheType: 'stale' })
+      .then(function(entries) {
+        expect(entries.length).to.be.equal(2);
+      });
+    });
   });
-});
+}
 
 describe('entry/entries', function() { // this is basically modelList
   var dm;