loopback-datasource-juggler/lib/abstract-class.js

596 lines
17 KiB
JavaScript

/**
* Module deps
*/
var Validatable = require('./validatable').Validatable;
var Hookable = require('./hookable').Hookable;
var util = require('util');
var jutil = require('./jutil');
exports.AbstractClass = AbstractClass;
jutil.inherits(AbstractClass, Validatable);
jutil.inherits(AbstractClass, Hookable);
/**
* Abstract class constructor
*/
function AbstractClass(data) {
var self = this;
var ds = this.constructor.schema.definitions[this.constructor.modelName];
var properties = ds.properties;
var settings = ds.setings;
data = data || {};
if (data.id) {
defineReadonlyProp(this, 'id', data.id);
}
Object.defineProperty(this, 'cachedRelations', {
writable: true,
enumerable: false,
configurable: true,
value: {}
});
Object.keys(properties).forEach(function (attr) {
var _attr = '_' + attr,
attr_was = attr + '_was';
// Hidden property to store currrent value
Object.defineProperty(this, _attr, {
writable: true,
enumerable: false,
configurable: true,
value: isdef(data[attr]) ? data[attr] :
(isdef(this[attr]) ? this[attr] : (
getDefault(attr)
))
});
// Public setters and getters
Object.defineProperty(this, attr, {
get: function () {
return this[_attr];
},
set: function (value) {
this[_attr] = value;
},
configurable: true,
enumerable: true
});
// Getter for initial property
Object.defineProperty(this, attr_was, {
writable: true,
value: data[attr],
configurable: true,
enumerable: false
});
}.bind(this));
function getDefault(attr) {
var def = properties[attr]['default']
if (isdef(def)) {
if (typeof def === 'function') {
return def();
} else {
return def;
}
} else {
return null;
}
}
this.trigger("initialize");
};
AbstractClass.defineProperty = function (prop, params) {
this.schema.defineProperty(this.modelName, prop, params);
};
/**
* @param data [optional]
* @param callback(err, obj)
*/
AbstractClass.create = function (data) {
var modelName = this.modelName;
// define callback manually
var callback = arguments[arguments.length - 1];
if (arguments.length == 0 || data === callback) {
data = {};
}
if (typeof callback !== 'function') {
callback = function () {};
}
var obj = null;
// if we come from save
if (data instanceof AbstractClass && !data.id) {
obj = data;
data = obj.toObject(true);
create();
} else {
obj = new this(data);
// validation required
obj.isValid(function (valid) {
if (!valid) {
callback(new Error('Validation error'), obj);
} else {
create();
}
});
}
function create() {
obj.trigger('create', function (done) {
this._adapter().create(modelName, data, function (err, id) {
if (id) {
defineReadonlyProp(obj, 'id', id);
this.constructor.cache[id] = obj;
}
done.call(this, function () {
if (callback) {
callback(err, obj);
}
});
}.bind(this));
});
}
};
AbstractClass.exists = function exists(id, cb) {
this.schema.adapter.exists(this.modelName, id, cb);
};
AbstractClass.find = function find(id, cb) {
this.schema.adapter.find(this.modelName, id, function (err, data) {
var obj = null;
if (data) {
if (this.cache[data.id]) {
obj = this.cache[data.id];
substractDirtyAttributes(obj, data);
this.call(obj, data);
} else {
obj = new this(data);
this.cache[data.id] = obj;
}
}
cb(err, obj);
}.bind(this));
};
/**
* Query collection of objects
* @param params {where: {}, order: '', limit: 1, offset: 0,...}
* @param cb (err, array of AbstractClass)
*/
AbstractClass.all = function all(params, cb) {
if (arguments.length === 1) {
cb = params;
params = null;
}
var constr = this;
this.schema.adapter.all(this.modelName, params, function (err, data) {
var collection = null;
if (data && data.map) {
collection = data.map(function (d) {
var obj = null;
// really questionable stuff
// goal is obvious: to not create different instances for the same object
// but the way it implemented...
// we can lost some dirty state of object, for example
// TODO: think about better implementation, test keeping dirty state
if (constr.cache[d.id]) {
obj = constr.cache[d.id];
// keep dirty attributes untouthed (remove from dataset)
substractDirtyAttributes(obj, d);
constr.call(obj, d);
} else {
obj = new constr(d);
constr.cache[d.id] = obj;
}
return obj;
});
cb(err, collection);
}
});
};
function substractDirtyAttributes(object, data) {
Object.keys(object.toObject()).forEach(function (attr) {
if (attr in data && object.propertyChanged(attr)) {
delete data[attr];
}
});
}
AbstractClass.destroyAll = function destroyAll(cb) {
this.schema.adapter.destroyAll(this.modelName, function (err) {
if (!err) {
Object.keys(this.cache).forEach(function (id) {
delete this.cache[id];
}.bind(this));
}
cb(err);
}.bind(this));
};
AbstractClass.count = function (cb) {
this.schema.adapter.count(this.modelName, cb);
};
AbstractClass.toString = function () {
return '[Model ' + this.modelName + ']';
}
/**
* Save instance. When instance haven't id, create method called instead.
* Triggers: validate, save, update | create
* @param options {validate: true, throws: false} [optional]
* @param callback(err, obj)
*/
AbstractClass.prototype.save = function (options, callback) {
if (typeof options == 'function') {
callback = options;
options = {};
}
callback = callback || function () {};
options = options || {};
if (!('validate' in options)) {
options.validate = true;
}
if (!('throws' in options)) {
options.throws = false;
}
if (options.validate) {
this.isValid(function (valid) {
if (valid) {
save.call(this);
} else {
var err = new Error('Validation error');
// throws option is dangerous for async usage
if (options.throws) {
throw err;
}
callback(err, this);
}
}.bind(this));
} else {
save.call(this);
}
function save() {
this.trigger('save', function (saveDone) {
var modelName = this.constructor.modelName;
var data = this.toObject(true);
var inst = this;
if (inst.id) {
inst.trigger('update', function (updateDone) {
inst._adapter().save(modelName, data, function (err) {
if (err) {
console.log(err);
} else {
inst.constructor.call(inst, data);
}
updateDone.call(inst, function () {
saveDone.call(inst, function () {
callback(err, inst);
});
});
});
});
} else {
inst.constructor.create(inst, function (err) {
saveDone.call(inst, function () {
callback(err, inst);
});
});
}
});
}
};
AbstractClass.prototype.isNewRecord = function () {
return !this.id;
};
AbstractClass.prototype._adapter = function () {
return this.constructor.schema.adapter;
};
AbstractClass.prototype.propertyChanged = function (name) {
return this[name + '_was'] !== this['_' + name];
};
AbstractClass.prototype.toObject = function (onlySchema) {
var data = {};
var ds = this.constructor.schema.definitions[this.constructor.modelName];
var properties = ds.properties;
// weird
Object.keys(onlySchema ? properties : this).concat(['id']).forEach(function (property) {
data[property] = this[property];
}.bind(this));
return data;
};
AbstractClass.prototype.destroy = function (cb) {
this.trigger('destroy', function (destroyed) {
this._adapter().destroy(this.constructor.modelName, this.id, function (err) {
delete this.constructor.cache[this.id];
destroyed(function () {
cb && cb(err);
});
}.bind(this));
});
};
AbstractClass.prototype.updateAttribute = function (name, value, cb) {
data = {};
data[name] = value;
this.updateAttributes(data, cb);
};
AbstractClass.prototype.updateAttributes = function updateAttributes(data, cb) {
var inst = this;
var model = this.constructor.modelName;
Object.keys(data).forEach(function (key) {
this[key] = data[key];
}.bind(this));
this.isValid(function (valid) {
if (!valid) {
if (cb) {
cb(new Error('Validation error'));
}
} else {
update.call(this);
}
}.bind(this));
function update() {
this.trigger('save', function (saveDone) {
this.trigger('update', function (done) {
Object.keys(data).forEach(function (key) {
data[key] = this[key];
}.bind(this));
this._adapter().updateAttributes(model, this.id, data, function (err) {
if (!err) {
Object.keys(data).forEach(function (key) {
inst[key] = data[key];
Object.defineProperty(inst, key + '_was', {
writable: false,
configurable: true,
enumerable: false,
value: data[key]
});
});
}
done.call(inst, function () {
saveDone.call(inst, function () {
cb(err);
});
});
}.bind(this));
});
});
}
};
/**
* Checks is property changed based on current property and initial value
* @param {attr} String - property name
* @return Boolean
*/
AbstractClass.prototype.propertyChanged = function (attr) {
return this['_' + attr] !== this[attr + '_was'];
};
AbstractClass.prototype.reload = function (cb) {
var obj = this.constructor.cache[this.id];
if (obj) {
obj.reset();
}
this.constructor.find(this.id, cb);
};
AbstractClass.prototype.reset = function () {
var obj = this;
Object.keys(obj).forEach(function (k) {
if (obj.propertyChanged(k)) {
obj[k] = obj[k + '_was'];
}
});
};
// relations
AbstractClass.hasMany = function (anotherClass, params) {
var methodName = params.as; // or pluralize(anotherClass.modelName)
var fk = params.foreignKey;
// each instance of this class should have method named
// pluralize(anotherClass.modelName)
// which is actually just anotherClass.all({where: {thisModelNameId: this.id}}, cb);
defineScope(this.prototype, anotherClass, methodName, function () {
var x = {};
x[fk] = this.id;
return {where: x};
}, {
find: find,
destroy: destroy
});
// obviously, anotherClass should have attribute called `fk`
anotherClass.schema.defineForeignKey(anotherClass.modelName, fk);
function find(id, cb) {
anotherClass.find(id, function (err, inst) {
if (err) return cb(err);
if (inst[fk] === this.id) {
cb(null, inst);
} else {
cb(new Error('Permission denied'));
}
}.bind(this));
}
function destroy(id, cb) {
this.find(id, function (err, inst) {
if (err) return cb(err);
if (inst) {
inst.destroy(cb);
} else {
cb(new Error('Not found'));
}
});
}
};
AbstractClass.belongsTo = function (anotherClass, params) {
var methodName = params.as;
var fk = params.foreignKey;
this.schema.defineForeignKey(anotherClass.modelName, fk);
this.prototype[methodName] = function (p, cb) {
if (p instanceof AbstractClass) { // acts as setter
this[fk] = p.id;
this.cachedRelations[methodName] = p;
} else if (typeof p === 'function') { // acts as async getter
this.find(this[fk], function (err, obj) {
if (err) return p(err);
this.cachedRelations[methodName] = obj;
}.bind(this));
} else if (!p) { // acts as sync getter
return this.cachedRelations[methodName] || this[fk];
}
};
};
AbstractClass.scope = function (name, params) {
defineScope(this, this, name, params);
};
function defineScope(cls, targetClass, name, params, methods) {
// collect meta info about scope
if (!cls._scopeMeta) {
cls._scopeMeta = {};
}
// anly make sence to add scope in meta if base and target classes
// are same
if (cls === targetClass) {
cls._scopeMeta[name] = params;
} else {
if (!targetClass._scopeMeta) {
targetClass._scopeMeta = {};
}
}
Object.defineProperty(cls, name, {
enumerable: false,
configurable: true,
get: function () {
var f = function caller(cond, cb) {
var actualCond;
if (arguments.length === 1) {
actualCond = {};
cb = cond;
} else if (arguments.length === 2) {
actualCond = cond;
} else {
throw new Error('Method only can be called with one or two arguments');
}
return targetClass.all(mergeParams(actualCond, caller._scope), cb);
};
f._scope = typeof params === 'function' ? params.call(this) : params;
f.build = build;
f.create = create;
f.destroyAll = destroyAll;
for (var i in methods) {
f[i] = methods;
}
// define sub-scopes
Object.keys(targetClass._scopeMeta).forEach(function (name) {
Object.defineProperty(f, name, {
enumerable: false,
get: function () {
mergeParams(f._scope, targetClass._scopeMeta[name]);
return f;
}
});
}.bind(this));
return f;
}
});
// and it should have create/build methods with binded thisModelNameId param
function build(data) {
data = data || {};
return new targetClass(mergeParams(this._scope, {where:data}).where);
}
function create(data, cb) {
if (typeof data === 'function') {
cb = data;
data = {};
}
this.build(data).save(cb);
}
function destroyAll(id, cb) {
// implement me
}
function mergeParams(base, update) {
if (update.where) {
base.where = merge(base.where, update.where);
}
// overwrite order
if (update.order) {
base.order = update.order;
}
return base;
}
}
// helper methods
//
function isdef(s) {
var undef;
return s !== undef;
}
function merge(base, update) {
base = base || {};
if (update) {
Object.keys(update).forEach(function (key) {
base[key] = update[key];
});
}
return base;
}
function defineReadonlyProp(obj, key, value) {
Object.defineProperty(obj, key, {
writable: false,
enumerable: true,
configurable: true,
value: value
});
}