loopback-connector/lib/connector.js

173 lines
4.4 KiB
JavaScript

module.exports = Connector;
/**
* Base class for LooopBack connector. This is more a collection of useful
* methods for connectors than a super class
* @constructor
*/
function Connector(name, settings) {
this._models = {};
this.name = name;
this.settings = settings || {};
}
/**
* Set the relational property to indicate the backend is a relational DB
* @type {boolean}
*/
Connector.prototype.relational = false;
/**
* Get types associated with the connector
* @returns {String[]} The types for the connector
*/
Connector.prototype.getTypes = function() {
return ['db', 'nosql'];
};
/**
* Get the default data type for ID
* @returns {Function} The default type for ID
*/
Connector.prototype.getDefaultIdType = function() {
return String;
};
/**
* Get the metadata for the connector
* @returns {Object} The metadata object
* @property {String} type The type for the backend
* @property {Function} defaultIdType The default id type
* @property {Boolean} [isRelational] If the connector represents a relational database
* @property {Object} schemaForSettings The schema for settings object
*/
Connector.prototype.getMedadata = function () {
if (!this._metadata) {
this._metadata = {
types: this.getTypes(),
defaultIdType: this.getDefaultIdType(),
isRelational: this.isRelational || (this.getTypes().indexOf('rdbms') !== -1),
schemaForSettings: {}
};
}
return this._metadata;
};
/**
* Execute a command with given parameters
* @param {String} command The command such as SQL
* @param {Object[]} [params] An array of parameters
* @param {Function} [callback] The callback function
*/
Connector.prototype.execute = function (command, params, callback) {
/*jshint unused:false */
throw new Error('query method should be declared in connector');
};
/**
* Look up the data source by model name
* @param {String} model The model name
* @returns {DataSource} The data source
*/
Connector.prototype.getDataSource = function (model) {
var m = this._models[model];
if (!m) {
console.trace('Model not found: ' + model);
}
return m && m.model.dataSource;
};
/**
* Get the id property name
* @param {String} model The model name
* @returns {String} The id property name
*/
Connector.prototype.idName = function (model) {
return this.getDataSource(model).idName(model);
};
/**
* Get the id property names
* @param {String} model The model name
* @returns {[String]} The id property names
*/
Connector.prototype.idNames = function (model) {
return this.getDataSource(model).idNames(model);
};
/**
* Get the id index (sequence number, starting from 1)
* @param {String} model The model name
* @param {String} prop The property name
* @returns {Number} The id index, undefined if the property is not part
* of the primary key
*/
Connector.prototype.id = function (model, prop) {
var p = this._models[model].properties[prop];
if (!p) {
console.trace('Property not found: ' + model + '.' + prop);
}
return p.id;
};
/**
* Hook to be called by DataSource for defining a model
* @param {Object} modelDefinition The model definition
*/
Connector.prototype.define = function (modelDefinition) {
if (!modelDefinition.settings) {
modelDefinition.settings = {};
}
this._models[modelDefinition.model.modelName] = modelDefinition;
};
/**
* Hook to be called by DataSource for defining a model property
* @param {String} model The model name
* @param {String} propertyName The property name
* @param {Object} propertyDefinition The object for property metadata
*/
Connector.prototype.defineProperty = function (model, propertyName, propertyDefinition) {
this._models[model].properties[propertyName] = propertyDefinition;
};
/**
* Disconnect from the connector
*/
Connector.prototype.disconnect = function disconnect(cb) {
// NO-OP
if (cb) process.nextTick(cb);
};
/**
* Get the id value for the given model
* @param {String} model The model name
* @param {Object} data The model instance data
* @returns {*} The id value
*
*/
Connector.prototype.getIdValue = function (model, data) {
return data && data[this.idName(model)];
};
/**
* Set the id value for the given model
* @param {String} model The model name
* @param {Object} data The model instance data
* @param {*} value The id value
*
*/
Connector.prototype.setIdValue = function (model, data, value) {
if (data) {
data[this.idName(model)] = value;
}
};
Connector.prototype.getType = function () {
return this.type;
};