419 lines
13 KiB
JavaScript
419 lines
13 KiB
JavaScript
/*!
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* Dependencies
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*/
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var i8n = require('inflection');
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var defineScope = require('./scope.js').defineScope;
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var ModelBaseClass = require('./model.js');
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module.exports = Relation;
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/**
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* Relations class
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*
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* @class Relation
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*/
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function Relation() {
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}
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/**
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* Find the relation by foreign key
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* @param {*} foreignKey The foreign key
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* @returns {Object} The relation object
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*/
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Relation.relationNameFor = function relationNameFor(foreignKey) {
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for (var rel in this.relations) {
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if (this.relations[rel].type === 'belongsTo' && this.relations[rel].keyFrom === foreignKey) {
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return rel;
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}
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}
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};
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/*!
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* Look up a model by name from the list of given models
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* @param {Object} models Models keyed by name
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* @param {String} modelName The model name
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* @returns {*} The matching model class
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*/
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function lookupModel(models, modelName) {
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if(models[modelName]) {
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return models[modelName];
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}
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var lookupClassName = modelName.toLowerCase();
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for (var name in models) {
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if (name.toLowerCase() === lookupClassName) {
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return models[name];
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}
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}
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}
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/**
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* Declare "hasMany" relation.
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* Example:
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* ```User.hasMany(Post, {as: 'posts', foreignKey: 'authorId'});```
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*
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* @param {Relation} anotherClass Class to has many
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* @param {Object} params Configuration {as:, foreignKey:}
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*/
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Relation.hasMany = function hasMany(anotherClass, params) {
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var thisClassName = this.modelName;
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params = params || {};
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if (typeof anotherClass === 'string') {
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params.as = anotherClass;
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if (params.model) {
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anotherClass = params.model;
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} else {
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var anotherClassName = i8n.singularize(anotherClass).toLowerCase();
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anotherClass = lookupModel(this.dataSource.modelBuilder.models, anotherClassName);
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}
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}
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var methodName = params.as || i8n.camelize(anotherClass.pluralModelName, true);
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var fk = params.foreignKey || i8n.camelize(thisClassName + '_id', true);
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var idName = this.dataSource.idName(this.modelName) || 'id';
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this.relations[methodName] = {
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type: 'hasMany',
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keyFrom: idName,
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keyTo: fk,
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modelTo: anotherClass,
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multiple: true
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};
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if (params.through) {
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this.relations[methodName].modelThrough = params.through;
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}
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// each instance of this class should have method named
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// pluralize(anotherClass.modelName)
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// which is actually just anotherClass.find({where: {thisModelNameId: this[idName]}}, cb);
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var scopeMethods = {
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findById: findById,
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destroy: destroyById
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};
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if (params.through) {
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var fk2 = i8n.camelize(anotherClass.modelName + '_id', true);
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// Create an instance of the target model and connect it to the instance of
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// the source model by creating an instance of the through model
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scopeMethods.create = function create(data, done) {
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if (typeof data !== 'object') {
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done = data;
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data = {};
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}
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if ('function' !== typeof done) {
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done = function () {
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};
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}
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var self = this;
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// First create the target model
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anotherClass.create(data, function (err, ac) {
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if (err) return done(err, ac);
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var d = {};
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d[params.through.relationNameFor(fk)] = self;
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d[params.through.relationNameFor(fk2)] = ac;
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// Then create the through model
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params.through.create(d, function (e) {
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if (e) {
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// Undo creation of the target model
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ac.destroy(function () {
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done(e);
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});
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} else {
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done(err, ac);
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}
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});
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});
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};
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/**
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* Add the target model instance to the 'hasMany' relation
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* @param {Object|ID) acInst The actual instance or id value
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*/
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scopeMethods.add = function (acInst, done) {
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var data = {};
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var query = {};
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query[fk] = this[idName];
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data[params.through.relationNameFor(fk)] = this;
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query[fk2] = acInst[idName] || acInst;
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data[params.through.relationNameFor(fk2)] = acInst;
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// Create an instance of the through model
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params.through.findOrCreate({where: query}, data, done);
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};
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/**
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* Remove the target model instance from the 'hasMany' relation
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* @param {Object|ID) acInst The actual instance or id value
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*/
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scopeMethods.remove = function (acInst, done) {
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var q = {};
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q[fk2] = acInst[idName] || acInst;
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params.through.findOne({where: q}, function (err, d) {
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if (err) {
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return done(err);
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}
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if (!d) {
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return done();
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}
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d.destroy(done);
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});
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};
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// No destroy method will be injected
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delete scopeMethods.destroy;
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}
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// Mix the property and scoped methods into the prototype class
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defineScope(this.prototype, params.through || anotherClass, methodName, function () {
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var filter = {};
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filter.where = {};
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filter.where[fk] = this[idName];
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if (params.through) {
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filter.collect = i8n.camelize(anotherClass.modelName, true);
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filter.include = filter.collect;
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}
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return filter;
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}, scopeMethods);
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if (!params.through) {
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// obviously, anotherClass should have attribute called `fk`
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anotherClass.dataSource.defineForeignKey(anotherClass.modelName, fk, this.modelName);
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}
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// Find the target model instance by id
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function findById(id, cb) {
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anotherClass.findById(id, function (err, inst) {
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if (err) {
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return cb(err);
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}
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if (!inst) {
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return cb(new Error('Not found'));
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}
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// Check if the foreign key matches the primary key
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if (inst[fk] && inst[fk].toString() === this[idName].toString()) {
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cb(null, inst);
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} else {
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cb(new Error('Permission denied'));
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}
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}.bind(this));
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}
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// Destroy the target model instance by id
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function destroyById(id, cb) {
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var self = this;
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anotherClass.findById(id, function (err, inst) {
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if (err) {
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return cb(err);
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}
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if (!inst) {
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return cb(new Error('Not found'));
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}
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// Check if the foreign key matches the primary key
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if (inst[fk] && inst[fk].toString() === self[idName].toString()) {
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inst.destroy(cb);
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} else {
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cb(new Error('Permission denied'));
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}
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});
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}
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};
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/**
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* Declare "belongsTo" relation.
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*
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* **Examples**
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*
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* Suppose the model Post has a *belongsTo* relationship with User (the author of the post). You could declare it this way:
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* ```js
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* Post.belongsTo(User, {as: 'author', foreignKey: 'userId'});
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* ```
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*
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* When a post is loaded, you can load the related author with:
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* ```js
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* post.author(function(err, user) {
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* // the user variable is your user object
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* });
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* ```
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*
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* The related object is cached, so if later you try to get again the author, no additional request will be made.
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* But there is an optional boolean parameter in first position that set whether or not you want to reload the cache:
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* ```js
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* post.author(true, function(err, user) {
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* // The user is reloaded, even if it was already cached.
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* });
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* ```
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* This optional parameter default value is false, so the related object will be loaded from cache if available.
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*
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* @param {Class} anotherClass Class to belong
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* @param {Object} params Configuration {as: 'propertyName', foreignKey: 'keyName'}
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*
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*/
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Relation.belongsTo = function (anotherClass, params) {
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params = params || {};
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if ('string' === typeof anotherClass) {
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params.as = anotherClass;
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if (params.model) {
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anotherClass = params.model;
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} else {
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var anotherClassName = anotherClass.toLowerCase();
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anotherClass = lookupModel(this.dataSource.modelBuilder.models, anotherClassName);
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}
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}
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var idName = this.dataSource.idName(anotherClass.modelName) || 'id';
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var methodName = params.as || i8n.camelize(anotherClass.modelName, true);
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var fk = params.foreignKey || methodName + 'Id';
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this.relations[methodName] = {
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type: 'belongsTo',
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keyFrom: fk,
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keyTo: idName,
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modelTo: anotherClass,
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multiple: false
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};
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this.dataSource.defineForeignKey(this.modelName, fk, anotherClass.modelName);
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this.prototype.__finders__ = this.prototype.__finders__ || {};
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// Set up a finder to find by id and make sure the foreign key of the declaring
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// model matches the primary key of the target model
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this.prototype.__finders__[methodName] = function (id, cb) {
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if (id === null) {
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cb(null, null);
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return;
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}
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anotherClass.findById(id, function (err, inst) {
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if (err) {
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return cb(err);
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}
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if (!inst) {
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return cb(null, null);
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}
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// Check if the foreign key matches the primary key
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if (inst[idName] === this[fk]) {
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cb(null, inst);
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} else {
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cb(new Error('Permission denied'));
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}
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}.bind(this));
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};
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// Define the method for the belongsTo relation itself
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// It will support one of the following styles:
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// - order.customer(refresh, callback): Load the target model instance asynchronously
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// - order.customer(customer): Synchronous setter of the target model instance
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// - order.customer(): Synchronous getter of the target model instance
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var relationMethod = function (refresh, p) {
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if (arguments.length === 1) {
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p = refresh;
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refresh = false;
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} else if (arguments.length > 2) {
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throw new Error('Method can\'t be called with more than two arguments');
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}
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var self = this;
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var cachedValue;
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if (!refresh && this.__cachedRelations && (this.__cachedRelations[methodName] !== undefined)) {
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cachedValue = this.__cachedRelations[methodName];
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}
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if (p instanceof ModelBaseClass) { // acts as setter
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this[fk] = p[idName];
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this.__cachedRelations[methodName] = p;
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} else if (typeof p === 'function') { // acts as async getter
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if (typeof cachedValue === 'undefined') {
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this.__finders__[methodName].apply(self, [this[fk], function (err, inst) {
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if (!err) {
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self.__cachedRelations[methodName] = inst;
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}
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p(err, inst);
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}]);
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return this[fk];
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} else {
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p(null, cachedValue);
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return cachedValue;
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}
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} else if (typeof p === 'undefined') { // acts as sync getter
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return this[fk];
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} else { // setter
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this[fk] = p;
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delete this.__cachedRelations[methodName];
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}
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};
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// Define a property for the scope so that we have 'this' for the scoped methods
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Object.defineProperty(this.prototype, methodName, {
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enumerable: false,
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configurable: true,
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get: function () {
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var fn = relationMethod.bind(this);
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// Set the remoting metadata so that it can be accessed as /api/<model>/<id>/<belongsToRelationName>
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// For example, /api/orders/1/customer
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fn.shared = true;
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fn.http = {verb: 'get', path: '/' + methodName};
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fn.accepts = {arg: 'refresh', type: 'boolean', http: {source: 'query'}};
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fn.description = 'Fetches belongsTo relation ' + methodName;
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fn.returns = {arg: methodName, type: 'object', root: true};
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// Create an instance of the target model and set the foreign key of the
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// declaring model instance to the id of the target instance
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fn.create = function(targetModelData, cb) {
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var self = this;
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anotherClass.create(targetModelData, function(err, targetModel) {
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if(!err) {
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self[fk] = targetModel[idName];
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cb && cb(err, targetModel);
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} else {
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cb && cb(err);
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}
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});
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}.bind(this);
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// Build an instance of the target model
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fn.build = function(targetModelData) {
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return new anotherClass(targetModelData);
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}.bind(this);
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return fn;
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}});
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};
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/**
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* Many-to-many relation
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*
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* For example, this creates connection model 'PostTag':
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* ```js
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* Post.hasAndBelongsToMany('tags');
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* ```
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* @param {String|Function} anotherClass - target class to hasAndBelongsToMany or name of
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* the relation
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* @param {Object} params - configuration {as: String, foreignKey: *, model: ModelClass}
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*/
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Relation.hasAndBelongsToMany = function hasAndBelongsToMany(anotherClass, params) {
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params = params || {};
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var models = this.dataSource.modelBuilder.models;
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if ('string' === typeof anotherClass) {
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params.as = anotherClass;
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if (params.model) {
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anotherClass = params.model;
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} else {
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anotherClass = lookupModel(models, i8n.singularize(anotherClass).toLowerCase()) ||
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anotherClass;
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}
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if (typeof anotherClass === 'string') {
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throw new Error('Could not find "' + anotherClass + '" relation for ' + this.modelName);
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}
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}
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if (!params.through) {
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var name1 = this.modelName + anotherClass.modelName;
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var name2 = anotherClass.modelName + this.modelName;
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params.through = lookupModel(models, name1) || lookupModel(models, name2) ||
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this.dataSource.define(name1);
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}
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params.through.belongsTo(this);
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params.through.belongsTo(anotherClass);
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this.hasMany(anotherClass, {as: params.as, through: params.through});
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};
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