Tidy up model building from data sources

See https://github.com/strongloop/loopback/issues/560

lib/datasource.js

@@ -1427,6 +1427,7 @@ DataSource.prototype.discoverSchemasSync = function (modelName, options) {
  */
 DataSource.prototype.discoverAndBuildModels = function (modelName, options, cb) {
   var self = this;
+  options = options || {};
   this.discoverSchemas(modelName, options, function (err, schemas) {
     if (err) {
       cb && cb(err, schemas);
@@ -1436,14 +1437,16 @@ DataSource.prototype.discoverAndBuildModels = function (modelName, options, cb)
     var schemaList = [];
     for (var s in schemas) {
       var schema = schemas[s];
+      if (options.base) {
+        schema.options = schema.options || {};
+        schema.options.base = options.base;
+      }
       schemaList.push(schema);
     }
 
-    var models = self.modelBuilder.buildModels(schemaList);
-    // Now attach the models to the data source
-    for (var m in models) {
-      models[m].attachTo(self);
-    }
+    var models = self.modelBuilder.buildModels(schemaList,
+      self.createModel.bind(self));
+
     cb && cb(err, models);
   });
 };
@@ -1462,18 +1465,41 @@ DataSource.prototype.discoverAndBuildModels = function (modelName, options, cb)
  * @param {Object} [options] The options
  */
 DataSource.prototype.discoverAndBuildModelsSync = function (modelName, options) {
+  options = options || {};
   var schemas = this.discoverSchemasSync(modelName, options);
 
   var schemaList = [];
   for (var s in schemas) {
     var schema = schemas[s];
+    if (options.base) {
+      schema.options = schema.options || {};
+      schema.options.base = options.base;
+    }
     schemaList.push(schema);
   }
 
-  var models = this.modelBuilder.buildModels(schemaList);
+  var models = this.modelBuilder.buildModels(schemaList,
+    this.createModel.bind(this));
+
   return models;
 };
 
+/**
+ * Introspect a JSON object and build a model class
+ * @param {String} name Name of the model
+ * @param {Object} json The json object representing a model instance
+ * @param {Object} options Options
+ * @returns {*}
+ */
+DataSource.prototype.buildModelFromInstance = function (name, json, options) {
+
+  // Introspect the JSON document to generate a schema
+  var schema = ModelBuilder.introspect(json);
+
+  // Create a model for the generated schema
+  return this.createModel(name, schema, options);
+};
+
 /**
  * Check whether migrations needed
  * This method applies only to SQL connectors.

lib/introspection.js

@@ -24,12 +24,13 @@ module.exports = function getIntrospector(ModelBuilder) {
       return 'date';
     }
 
+    var itemType;
     if (Array.isArray(value)) {
       for (var i = 0; i < value.length; i++) {
         if (value[i] === null || value[i] === undefined) {
           continue;
         }
-        var itemType = introspectType(value[i]);
+        itemType = introspectType(value[i]);
         if (itemType) {
           return [itemType];
         }
@@ -43,7 +44,7 @@ module.exports = function getIntrospector(ModelBuilder) {
 
     var properties = {};
     for (var p in value) {
-      var itemType = introspectType(value[p]);
+      itemType = introspectType(value[p]);
       if (itemType) {
         properties[p] = itemType;
       }
@@ -54,6 +55,7 @@ module.exports = function getIntrospector(ModelBuilder) {
     return properties;
   }
 
+  ModelBuilder.introspect = introspectType;
   return introspectType;
 }
 

lib/model-builder.js

@@ -632,7 +632,7 @@ ModelBuilder.prototype.resolveType = function (type) {
  * @param {*} schemas The schemas
  * @returns {Object} A map of model constructors keyed by model name
  */
-ModelBuilder.prototype.buildModels = function (schemas) {
+ModelBuilder.prototype.buildModels = function (schemas, createModel) {
   var models = {};
 
   // Normalize the schemas to be an array of the schema objects {name: <name>, properties: {}, options: {}}
@@ -656,7 +656,12 @@ ModelBuilder.prototype.buildModels = function (schemas) {
   for (var s in schemas) {
     var name = this.getSchemaName(schemas[s].name);
     schemas[s].name = name;
-    var model = this.define(schemas[s].name, schemas[s].properties, schemas[s].options);
+    var model;
+    if(typeof createModel === 'function') {
+      model = createModel(schemas[s].name, schemas[s].properties, schemas[s].options);
+    } else {
+      model = this.define(schemas[s].name, schemas[s].properties, schemas[s].options);
+    }
     models[name] = model;
     relations = relations.concat(model.definition.relations);
   }

test/introspection.test.js

@@ -1,8 +1,29 @@
 var assert = require('assert');
-var ModelBuilder = require('../lib/model-builder').ModelBuilder;
+var ModelBuilder = require('..').ModelBuilder;
+var DataSource = require('../').DataSource;
 var introspectType = require('../lib/introspection')(ModelBuilder);
 var traverse = require('traverse');
 
+var json = {
+  name: 'Joe',
+  age: 30,
+  birthday: new Date(),
+  vip: true,
+  address: {
+    street: '1 Main St',
+    city: 'San Jose',
+    state: 'CA',
+    zipcode: '95131',
+    country: 'US'
+  },
+  friends: ['John', 'Mary'],
+  emails: [
+    {label: 'work', id: 'x@sample.com'},
+    {label: 'home', id: 'x@home.com'}
+  ],
+  tags: []
+};
+
 describe('Introspection of model definitions from JSON', function () {
 
   it('should handle simple types', function () {
@@ -61,27 +82,6 @@ describe('Introspection of model definitions from JSON', function () {
   });
 
   it('should build a model from the introspected schema', function (done) {
-
-    var json = {
-      name: 'Joe',
-      age: 30,
-      birthday: new Date(),
-      vip: true,
-      address: {
-        street: '1 Main St',
-        city: 'San Jose',
-        state: 'CA',
-        zipcode: '95131',
-        country: 'US'
-      },
-      friends: ['John', 'Mary'],
-      emails: [
-        {label: 'work', id: 'x@sample.com'},
-        {label: 'home', id: 'x@home.com'}
-      ],
-      tags: []
-    };
-
     var copy = traverse(json).clone();
 
     var schema = introspectType(json);
@@ -97,5 +97,33 @@ describe('Introspection of model definitions from JSON', function () {
     assert.deepEqual(obj, copy);
     done();
   });
+
+  it('should build a model using buildModelFromInstance', function (done) {
+    var copy = traverse(json).clone();
+
+    var builder = new ModelBuilder();
+    var Model = builder.buildModelFromInstance('MyModel', copy, {idInjection: false});
+
+    var obj = new Model(json);
+    obj = obj.toObject();
+    assert.deepEqual(obj, copy);
+    done();
+  });
+
+  it('should build a model using DataSource.buildModelFromInstance', function (done) {
+    var copy = traverse(json).clone();
+
+    var builder = new DataSource('memory');
+    var Model = builder.buildModelFromInstance('MyModel', copy,
+      {idInjection: false});
+
+    assert.equal(Model.dataSource, builder);
+
+    var obj = new Model(json);
+    obj = obj.toObject();
+    assert.deepEqual(obj, copy);
+    done();
+  });
+
 });
 

test/loopback-dl.test.js

@@ -1418,7 +1418,6 @@ describe('DataAccessObject', function () {
 });
 
 describe('Load models from json', function () {
-  it('should be able to define models from json', function () {
   var path = require('path'),
     fs = require('fs');
 
@@ -1428,18 +1427,22 @@ describe('Load models from json', function () {
    * @returns A map of schemas keyed by name
    */
   function loadSchemasSync(schemaFile, dataSource) {
+    var modelBuilder, createModel;
     // Set up the data source
     if (!dataSource) {
-        dataSource = new DataSource('memory');
+      modelBuilder = new ModelBuilder();
+    } else {
+      modelBuilder = dataSource.modelBuilder;
+      createModel = dataSource.createModel.bind(dataSource);
     }
 
     // Read the dataSource JSON file
     var schemas = JSON.parse(fs.readFileSync(schemaFile));
-
-      return dataSource.modelBuilder.buildModels(schemas);
-
+    return modelBuilder.buildModels(schemas, createModel);
   }
 
+  it('should be able to define models from json', function () {
+
     var models = loadSchemasSync(path.join(__dirname, 'test1-schemas.json'));
 
     models.should.have.property('AnonymousModel_0');
@@ -1459,6 +1462,16 @@ describe('Load models from json', function () {
     }
   });
 
+  it('should be able to define models from json using dataSource', function() {
+    var ds = new DataSource('memory');
+
+    var models = loadSchemasSync(path.join(__dirname, 'test2-schemas.json'), ds);
+    models.should.have.property('Address');
+    models.should.have.property('Account');
+    models.should.have.property('Customer');
+    assert.equal(models.Address.dataSource, ds);
+  });
+
   it('should allow customization of default model base class', function () {
     var modelBuilder = new ModelBuilder();