feat: remove all references to a Model

Add API allowing applications to hide a Model from the
REST API and remove all references to it, allowing Garbage Collector
to claim all memory used by the model.

lib/application.js

@@ -163,6 +163,44 @@ app.model = function(Model, config) {
   return Model;
 };
 
+/**
+ * Remove all references to a previously registered Model.
+ *
+ * The method emits "modelDeleted" event as a counter-part to "modelRemoted"
+ * event.
+ *
+ * @param {String} modelName The name of the model to remove.
+ */
+app.deleteModelByName = function(modelName) {
+  const ModelCtor = this.models[modelName];
+  delete this.models[modelName];
+  delete this.models[classify(modelName)];
+  delete this.models[camelize(modelName)];
+
+  if (ModelCtor) {
+    ModelCtor.removeAllListeners();
+
+    const ix = this._models.indexOf(ModelCtor);
+    if (ix > -1) {
+      this._models.splice(ix, 1);
+    }
+  }
+
+  const remotes = this.remotes();
+  remotes.deleteClassByName(modelName);
+  remotes.deleteTypeByName(modelName);
+
+  if (ModelCtor && ModelCtor.dataSource) {
+    ModelCtor.dataSource.deleteModelByName(modelName);
+  } else {
+    this.registry.modelBuilder.deleteModelByName(modelName);
+  }
+
+  clearHandlerCache(this);
+
+  this.emit('modelDeleted', ModelCtor || modelName);
+};
+
 /**
  * Get the models exported by the app. Returns only models defined using `app.model()`
  *

package.json

@@ -49,15 +49,15 @@
     "inflection": "^1.6.0",
     "isemail": "^2.2.1",
     "loopback-connector-remote": "^3.0.0",
-    "loopback-datasource-juggler": "^3.15.0",
+    "loopback-datasource-juggler": "^3.18.0",
     "loopback-filters": "^1.0.0",
     "loopback-phase": "^3.0.0",
     "nodemailer": "^2.5.0",
     "nodemailer-stub-transport": "^1.0.0",
     "serve-favicon": "^2.2.0",
     "stable": "^0.1.5",
     "strong-globalize": "^3.1.0",
-    "strong-remoting": "^3.0.0",
+    "strong-remoting": "^3.11.0",
     "uid2": "0.0.3",
     "underscore.string": "^3.0.3"
   },

test/app.test.js

@@ -17,11 +17,12 @@ var describe = require('./util/describe');
 var expect = require('./helpers/expect');
 var it = require('./util/it');
 var request = require('supertest');
+const sinon = require('sinon');
 
 describe('app', function() {
   var app;
   beforeEach(function() {
-    app = loopback();
+    app = loopback({localRegistry: true, loadBuiltinModels: true});
   });
 
   describe.onServer('.middleware(phase, handler)', function() {
@@ -763,6 +764,66 @@ describe('app', function() {
     });
   });
 
+  describe('app.deleteModelByName()', () => {
+    let TestModel;
+    beforeEach(setupTestModel);
+
+    it('removes the model from app registries', () => {
+      expect(Object.keys(app.models))
+        .to.contain('test-model')
+        .and.contain('TestModel')
+        .and.contain('testModel');
+      expect(app.models().map(m => m.modelName))
+        .to.contain('test-model');
+
+      app.deleteModelByName('test-model');
+
+      expect(Object.keys(app.models))
+        .to.not.contain('test-model')
+        .and.not.contain('TestModel')
+        .and.not.contain('testModel');
+      expect(app.models().map(m => m.modelName))
+        .to.not.contain('test-model');
+    });
+
+    it('removes the model from juggler registries', () => {
+      expect(Object.keys(app.registry.modelBuilder.models))
+        .to.contain('test-model');
+
+      app.deleteModelByName('test-model');
+
+      expect(Object.keys(app.registry.modelBuilder.models))
+        .to.not.contain('test-model');
+    });
+
+    it('removes the model from remoting registries', () => {
+      expect(Object.keys(app.remotes()._classes))
+        .to.contain('test-model');
+
+      app.deleteModelByName('test-model');
+
+      expect(Object.keys(app.remotes()._classes))
+        .to.not.contain('test-model');
+    });
+
+    it('emits "modelDeleted" event', () => {
+      const spy = sinon.spy();
+      app.on('modelDeleted', spy);
+
+      app.deleteModelByName('test-model');
+
+      sinon.assert.calledWith(spy, TestModel);
+    });
+
+    function setupTestModel() {
+      TestModel = app.registry.createModel({
+        name: 'test-model',
+        base: 'Model',
+      });
+      app.model(TestModel, {dataSource: null});
+    }
+  });
+
   describe('app.models', function() {
     it('is unique per app instance', function() {
       app.dataSource('db', {connector: 'memory'});

test/rest.middleware.test.js

@@ -200,6 +200,18 @@ describe('loopback.rest', function() {
     }, done);
   });
 
+  it('rebuilds REST endpoints after a model was deleted', () => {
+    app.model(MyModel);
+    app.use(loopback.rest());
+
+    return request(app).get('/mymodels').expect(200)
+      .then(() => {
+        app.deleteModelByName('MyModel');
+
+        return request(app).get('/mymodels').expect(404);
+      });
+  });
+
   function givenUserModelWithAuth() {
     var AccessToken = app.registry.getModel('AccessToken');
     app.model(AccessToken, {dataSource: 'db'});