loopback-datasource-juggler/lib/schema.js

162 lines
4.4 KiB
JavaScript

/**
* Module dependencies
*/
var AbstractClass = require('./abstract-class').AbstractClass;
var util = require('util');
/**
* Export public API
*/
exports.Schema = Schema;
// exports.AbstractClass = AbstractClass;
/**
* Helpers
*/
var slice = Array.prototype.slice;
/**
* Shema - classes factory
* @param name - type of schema adapter (mysql, mongoose, sequelize, redis)
* @param settings - any database-specific settings which we need to
* establish connection (of course it depends on specific adapter)
*/
function Schema(name, settings) {
// just save everything we get
this.name = name;
this.settings = settings;
// create blank models pool
this.models = {};
this.definitions = {};
// and initialize schema using adapter
// this is only one initialization entry point of adapter
// this module should define `adapter` member of `this` (schema)
var adapter;
try {
adapter = require('./adapters/' + name);
} catch (e) {
try {
adapter = require(name);
} catch (e) {
throw new Error('Adapter ' + name + ' is not defined, try\n npm install ' + name);
}
}
adapter.initialize(this, function () {
this.connected = true;
this.emit('connected');
}.bind(this));
// we have an adaper now?
if (!this.adapter) {
throw new Error('Adapter is not defined correctly: it should create `adapter` member of schema');
}
};
util.inherits(Schema, process.EventEmitter);
function Text() {
}
Schema.Text = Text;
Schema.prototype.automigrate = function (cb) {
if (this.adapter.freezeSchema) {
this.adapter.freezeSchema();
}
if (this.adapter.automigrate) {
this.adapter.automigrate(cb);
} else {
cb && cb();
}
};
/**
* Define class
* @param className
* @param properties - hash of class properties in format
* {property: Type, property2: Type2, ...}
* or
* {property: {type: Type}, property2: {type: Type2}, ...}
* @param settings - other configuration of class
*/
Schema.prototype.define = function defineClass(className, properties, settings) {
var schema = this;
var args = slice.call(arguments);
if (!className) throw new Error('Class name required');
if (args.length == 1) properties = {}, args.push(properties);
if (args.length == 2) settings = {}, args.push(settings);
standartize(properties, settings);
// every class can receive hash of data as optional param
var newClass = function (data) {
AbstractClass.call(this, data);
};
hiddenProperty(newClass, 'schema', schema);
hiddenProperty(newClass, 'modelName', className);
hiddenProperty(newClass, 'cache', {});
// setup inheritance
newClass.__proto__ = AbstractClass;
util.inherits(newClass, AbstractClass);
// store class in model pool
this.models[className] = newClass;
this.definitions[className] = {
properties: properties,
settings: settings
};
// pass controll to adapter
this.adapter.define({
model: newClass,
properties: properties,
settings: settings
});
return newClass;
function standartize(properties, settings) {
Object.keys(properties).forEach(function (key) {
var v = properties[key];
if (typeof v === 'function') {
properties[key] = { type: v };
}
});
// TODO: add timestamps fields
// when present in settings: {timestamps: true}
// or {timestamps: {created: 'created_at', updated: false}}
// by default property names: createdAt, updatedAt
}
};
Schema.prototype.defineForeignKey = function defineForeignKey(className, key) {
// return if already defined
if (this.definitions[className].properties[key]) return;
if (this.adapter.defineForeignKey) {
this.adapter.defineForeignKey(className, key, function (err, keyType) {
if (err) throw err;
this.definitions[className].properties[key] = keyType;
}.bind(this));
} else {
this.definitions[className].properties[key] = Number;
}
};
function hiddenProperty(where, property, value) {
Object.defineProperty(where, property, {
writable: false,
enumerable: false,
configurable: false,
value: value
});
}