Basic plugin architecture

index.js

@@ -1,3 +1,4 @@
+exports.mixins = require('./lib/mixins'); // require before ModelBuilder below - why?
 exports.ModelBuilder = exports.LDL = require('./lib/model-builder.js').ModelBuilder;
 exports.DataSource = exports.Schema = require('./lib/datasource.js').DataSource;
 exports.ModelBaseClass = require('./lib/model.js');

lib/mixins.js

@@ -0,0 +1,87 @@
+var fs = require('fs');
+var path = require('path');
+var extend = require('util')._extend;
+var inflection = require('inflection');
+var debug = require('debug')('loopback:mixin');
+var ModelBuilder = require('./model-builder').ModelBuilder;
+
+var registry = exports.registry = {};
+var modelBuilder = new ModelBuilder();
+
+exports.apply = function applyMixin(modelClass, name, options) {
+  name = inflection.classify(name.replace(/-/g, '_'));
+  var fn = registry[name];
+  if (typeof fn === 'function') {
+    if (modelClass.dataSource) {
+      fn(modelClass, options || {});
+    } else {
+      modelClass.once('dataSourceAttached', function() {
+        fn(modelClass, options || {});
+      });
+    }
+  } else {
+    debug('Invalid mixin: %s', name);
+  }
+};
+
+var defineMixin = exports.define = function defineMixin(name, mixin, ldl) {
+  if (typeof mixin === 'function' || typeof mixin === 'object') {
+    name = inflection.classify(name.replace(/-/g, '_'));
+    if (registry[name]) {
+      debug('Duplicate mixin: %s', name);
+    } else {
+      debug('Defining mixin: %s', name);
+    }
+    if (typeof mixin === 'object' && ldl) {
+      var model = modelBuilder.define(name, mixin);
+      registry[name] = function(Model, options) {
+        Model.mixin(model, options);
+      };
+    } else if (typeof mixin === 'object') {
+      registry[name] = function(Model, options) {
+        extend(Model.prototype, mixin);
+      };
+    } else if (typeof mixin === 'function') {
+      registry[name] = mixin;
+    }
+  } else {
+    debug('Invalid mixin function: %s', name);
+  }
+};
+
+var loadMixins = exports.load = function loadMixins(dir) {
+  var files = tryReadDir(path.resolve(dir));
+  files.forEach(function(filename) {
+    var filepath = path.resolve(path.join(dir, filename));
+    var ext = path.extname(filename);
+    var name = path.basename(filename, ext);
+    var stats = fs.statSync(filepath);
+    if (stats.isFile()) {
+      if (ext in require.extensions) {
+        var mixin = tryRequire(filepath);
+        if (typeof mixin === 'function' 
+          || typeof mixin === 'object') {
+          defineMixin(name, mixin, ext === '.json');
+        }
+      }
+    }
+  });
+};
+
+loadMixins(path.join(__dirname, 'mixins'));
+
+function tryReadDir() {
+  try {
+    return fs.readdirSync.apply(fs, arguments);
+  } catch(e) {
+    return [];
+  }
+};
+
+function tryRequire(file) {
+  try {
+    return require(file);
+  } catch(e) {
+  }
+};
+

lib/mixins/time-stamp.js

@@ -0,0 +1,23 @@
+module.exports = function timestamps(Model, options) {
+
+  Model.defineProperty('createdAt', { type: 'date' });
+  Model.defineProperty('updatedAt', { type: 'date' });
+
+  var originalBeforeSave = Model.beforeSave;
+  Model.beforeSave = function(next, data) {
+      Model.applyTimestamps(data, this.isNewRecord());
+      if (data.createdAt) this.createdAt = data.createdAt;
+      if (data.updatedAt) this.updatedAt = data.updatedAt;
+      if (originalBeforeSave) {
+          originalBeforeSave.apply(this, arguments);
+      } else {
+          next();
+      }
+  };
+
+  Model.applyTimestamps = function(data, creation) {
+      data.updatedAt = new Date();
+      if (creation) data.createdAt = data.updatedAt; 
+  };
+
+};

lib/model-builder.js

@@ -10,6 +10,7 @@ var DefaultModelBaseClass = require('./model.js');
 var List = require('./list.js');
 var ModelDefinition = require('./model-definition.js');
 var mergeSettings = require('./utils').mergeSettings;
+var mixins = require('./mixins');
 
 // Set up types
 require('./types')(ModelBuilder);
@@ -428,6 +429,22 @@ ModelBuilder.prototype.define = function defineClass(className, properties, sett
     ModelClass.registerProperty(propertyName);
   }
 
+  var mixinSettings = settings.mixins || {};
+  var keys = Object.keys(mixinSettings);
+  var size = keys.length;
+  for (i = 0; i < size; i++) {
+    var name = keys[i];
+    var mixin = mixinSettings[name];
+    if (mixin === true) mixin = {};
+    if (typeof mixin === 'object') {
+      mixinSettings[name] = true;
+      mixins.apply(ModelClass, name, mixin);
+    } else {
+      // for settings metadata
+      mixinSettings[name] = false;
+    }
+  }
+
   ModelClass.emit('defined', ModelClass);
 
   return ModelClass;

lib/model.js

@@ -12,6 +12,7 @@ var jutil = require('./jutil');
 var List = require('./list');
 var Hookable = require('./hooks');
 var validations = require('./validations.js');
+var mixins = require('./mixins');
 
 // Set up an object for quick lookup
 var BASE_TYPES = {
@@ -387,7 +388,11 @@ ModelBaseClass.prototype.inspect = function () {
 };
 
 ModelBaseClass.mixin = function (anotherClass, options) {
-  return jutil.mixin(this, anotherClass, options);
+  if (typeof anotherClass === 'string') {
+    mixins.apply(this, anotherClass, options);
+  } else {
+    return jutil.mixin(this, anotherClass, options);
+  }
 };
 
 ModelBaseClass.prototype.getDataSource = function () {

test/fixtures/mixins/address.json

@@ -0,0 +1,12 @@
+{
+  "properties": {
+    "street": {
+      "type": "string",
+      "required": true
+    },
+    "city": {
+      "type": "string",
+      "required": true
+    }
+  }
+}

test/fixtures/mixins/demo.js

@@ -0,0 +1,5 @@
+module.exports = function timestamps(Model, options) {
+
+  Model.demoMixin = options.ok;
+
+};

test/fixtures/mixins/other.js

@@ -0,0 +1,3 @@
+module.exports = { 
+  otherMixin: true
+}

test/mixins.test.js

@@ -0,0 +1,82 @@
+// This test written in mocha+should.js
+var should = require('./init.js');
+var assert = require('assert');
+var path = require('path');
+
+var jdb = require('../');
+var ModelBuilder = jdb.ModelBuilder;
+var DataSource = jdb.DataSource;
+var Memory = require('../lib/connectors/memory');
+
+var mixins = jdb.mixins;
+
+describe('Model class', function () {
+
+  it('should define a mixin', function() {
+    mixins.define('Example', function(Model, options) {
+      Model.prototype.example = function() {
+        return options;
+      };
+    });
+  });
+
+  it('should load mixins from directory', function() {
+    var expected = [ 'TimeStamp', 'Example', 'Address', 'Demo', 'Other' ];
+    mixins.load(path.join(__dirname, 'fixtures', 'mixins'));
+    mixins.registry.should.have.property('TimeStamp');
+    mixins.registry.should.have.property('Example');
+    mixins.registry.should.have.property('Address');
+    mixins.registry.should.have.property('Demo');
+    mixins.registry.should.have.property('Other');
+  });
+
+  it('should apply a mixin class', function() {
+    var memory = new DataSource({connector: Memory});
+    var Item = memory.createModel('Item', { name: 'string' }, {
+      mixins: { TimeStamp: true, demo: true, Address: true }
+    });
+
+    var modelBuilder = new ModelBuilder();
+    var Address = modelBuilder.define('Address', {
+      street: { type: 'string', required: true },
+      city: { type: 'string', required: true }
+    });
+
+    Item.mixin(Address);
+
+    var def = memory.getModelDefinition('Item');
+    var properties = def.toJSON().properties;
+
+    // properties.street.should.eql({ type: 'String', required: true });
+    // properties.city.should.eql({ type: 'String', required: true });
+  });
+
+  it('should apply mixins', function(done) {
+    var memory = new DataSource({connector: Memory});
+    var Item = memory.createModel('Item', { name: 'string' }, {
+      mixins: { TimeStamp: true, demo: { ok: true }, Address: true }
+    });
+
+    Item.mixin('Example', { foo: 'bar' });
+    Item.mixin('other');
+
+    var def = memory.getModelDefinition('Item');
+    var properties = def.toJSON().properties;
+    properties.createdAt.should.eql({ type: 'Date' });
+    properties.updatedAt.should.eql({ type: 'Date' });
+
+    // properties.street.should.eql({ type: 'String', required: true });
+    // properties.city.should.eql({ type: 'String', required: true });
+
+    Item.demoMixin.should.be.true;
+    Item.prototype.otherMixin.should.be.true;
+
+    Item.create({ name: 'Item 1' }, function(err, inst) {
+      inst.createdAt.should.be.a.date;
+      inst.updatedAt.should.be.a.date;
+      inst.example().should.eql({ foo: 'bar' });
+      done();
+    });
+  });
+
+});