// Copyright IBM Corp. 2014,2016. All Rights Reserved.
// Node module: loopback
// This file is licensed under the MIT License.
// License text available at https://opensource.org/licenses/MIT
/*!
* Module Dependencies.
*/
'use strict';
var g = require('./globalize');
var runtime = require('./runtime');
var assert = require('assert');
var async = require('async');
var deprecated = require('depd')('loopback');
var debug = require('debug')('loopback:persisted-model');
var PassThrough = require('stream').PassThrough;
var utils = require('./utils');
var REPLICATION_CHUNK_SIZE = -1;
module.exports = function(registry) {
var Model = registry.getModel('Model');
/**
* Extends Model with basic query and CRUD support.
*
* **Change Event**
*
* Listen for model changes using the `change` event.
*
* ```js
* MyPersistedModel.on('changed', function(obj) {
* console.log(obj) // => the changed model
* });
* ```
*
* @class PersistedModel
*/
var PersistedModel = Model.extend('PersistedModel');
/*!
* Setup the `PersistedModel` constructor.
*/
PersistedModel.setup = function setupPersistedModel() {
// call Model.setup first
Model.setup.call(this);
var PersistedModel = this;
// enable change tracking (usually for replication)
if (this.settings.trackChanges) {
PersistedModel._defineChangeModel();
PersistedModel.once('dataSourceAttached', function() {
PersistedModel.enableChangeTracking();
});
} else if (this.settings.enableRemoteReplication) {
PersistedModel._defineChangeModel();
}
PersistedModel.setupRemoting();
};
/*!
* Throw an error telling the user that the method is not available and why.
*/
function throwNotAttached(modelName, methodName) {
throw new Error(
g.f('Cannot call %s.%s().' +
' The %s method has not been setup.' +
' The {{PersistedModel}} has not been correctly attached to a {{DataSource}}!',
modelName, methodName, methodName)
);
}
/*!
* Convert null callbacks to 404 error objects.
* @param {HttpContext} ctx
* @param {Function} cb
*/
function convertNullToNotFoundError(ctx, cb) {
if (ctx.result !== null) return cb();
var modelName = ctx.method.sharedClass.name;
var id = ctx.getArgByName('id');
var msg = g.f('Unknown "%s" {{id}} "%s".', modelName, id);
var error = new Error(msg);
error.statusCode = error.status = 404;
error.code = 'MODEL_NOT_FOUND';
cb(error);
}
/**
* Create new instance of Model, and save to database.
*
* @param {Object|Object[]} [data] Optional data argument. Can be either a single model instance or an array of instances.
*
* @callback {Function} callback Callback function called with `cb(err, obj)` signature.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Object} models Model instances or null.
*/
PersistedModel.create = function(data, callback) {
throwNotAttached(this.modelName, 'create');
};
/**
* Update or insert a model instance
* @param {Object} data The model instance data to insert.
* @callback {Function} callback Callback function called with `cb(err, obj)` signature.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Object} model Updated model instance.
*/
PersistedModel.upsert = PersistedModel.updateOrCreate = PersistedModel.patchOrCreate =
function upsert(data, callback) {
throwNotAttached(this.modelName, 'upsert');
};
/**
* Update or insert a model instance based on the search criteria.
* If there is a single instance retrieved, update the retrieved model.
* Creates a new model if no model instances were found.
* Returns an error if multiple instances are found.
* @param {Object} [where] `where` filter, like
* ```
* { key: val, key2: {gt: 'val2'}, ...}
* ```
*
see
* [Where filter](http://loopback.io/doc/en/lb2/Where-filter.html#where-clause-for-other-methods).
* @param {Object} data The model instance data to insert.
* @callback {Function} callback Callback function called with `cb(err, obj)` signature.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Object} model Updated model instance.
*/
PersistedModel.upsertWithWhere =
PersistedModel.patchOrCreateWithWhere = function upsertWithWhere(where, data, callback) {
throwNotAttached(this.modelName, 'upsertWithWhere');
};
/**
* Replace or insert a model instance; replace existing record if one is found,
* such that parameter `data.id` matches `id` of model instance; otherwise,
* insert a new record.
* @param {Object} data The model instance data.
* @options {Object} [options] Options for replaceOrCreate
* @property {Boolean} validate Perform validation before saving. Default is true.
* @callback {Function} callback Callback function called with `cb(err, obj)` signature.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Object} model Replaced model instance.
*/
PersistedModel.replaceOrCreate = function replaceOrCreate(data, callback) {
throwNotAttached(this.modelName, 'replaceOrCreate');
};
/**
* Finds one record matching the optional filter object. If not found, creates
* the object using the data provided as second argument. In this sense it is
* the same as `find`, but limited to one object. Returns an object, not
* collection. If you don't provide the filter object argument, it tries to
* locate an existing object that matches the `data` argument.
*
* @options {Object} [filter] Optional Filter object; see below.
* @property {String|Object|Array} fields Identify fields to include in return result.
*
See [Fields filter](http://loopback.io/doc/en/lb2/Fields-filter.html).
* @property {String|Object|Array} include See PersistedModel.include documentation.
*
See [Include filter](http://loopback.io/doc/en/lb2/Include-filter.html).
* @property {Number} limit Maximum number of instances to return.
*
See [Limit filter](http://loopback.io/doc/en/lb2/Limit-filter.html).
* @property {String} order Sort order: either "ASC" for ascending or "DESC" for descending.
*
See [Order filter](http://loopback.io/doc/en/lb2/Order-filter.html).
* @property {Number} skip Number of results to skip.
*
See [Skip filter](http://loopback.io/doc/en/lb2/Skip-filter.html).
* @property {Object} where Where clause, like
* ```
* {where: {key: val, key2: {gt: val2}, ...}}
* ```
*
See
* [Where filter](http://loopback.io/doc/en/lb2/Where-filter.html#where-clause-for-queries).
* @param {Object} data Data to insert if object matching the `where` filter is not found.
* @callback {Function} callback Callback function called with `cb(err, instance, created)` arguments. Required.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Object} instance Model instance matching the `where` filter, if found.
* @param {Boolean} created True if the instance does not exist and gets created.
*/
PersistedModel.findOrCreate = function findOrCreate(query, data, callback) {
throwNotAttached(this.modelName, 'findOrCreate');
};
PersistedModel.findOrCreate._delegate = true;
/**
* Check whether a model instance exists in database.
*
* @param {id} id Identifier of object (primary key value).
*
* @callback {Function} callback Callback function called with `(err, exists)` arguments. Required.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Boolean} exists True if the instance with the specified ID exists; false otherwise.
*/
PersistedModel.exists = function exists(id, cb) {
throwNotAttached(this.modelName, 'exists');
};
/**
* Find object by ID with an optional filter for include/fields.
*
* @param {*} id Primary key value
* @options {Object} [filter] Optional Filter JSON object; see below.
* @property {String|Object|Array} fields Identify fields to include in return result.
*
See [Fields filter](http://loopback.io/doc/en/lb2/Fields-filter.html).
* @property {String|Object|Array} include See PersistedModel.include documentation.
*
See [Include filter](http://loopback.io/doc/en/lb2/Include-filter.html).
* @callback {Function} callback Callback function called with `(err, instance)` arguments. Required.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Object} instance Model instance matching the specified ID or null if no instance matches.
*/
PersistedModel.findById = function findById(id, filter, cb) {
throwNotAttached(this.modelName, 'findById');
};
/**
* Find all model instances that match `filter` specification.
* See [Querying models](http://loopback.io/doc/en/lb2/Querying-data.html).
*
* @options {Object} [filter] Optional Filter JSON object; see below.
* @property {String|Object|Array} fields Identify fields to include in return result.
*
See [Fields filter](http://loopback.io/doc/en/lb2/Fields-filter.html).
* @property {String|Object|Array} include See PersistedModel.include documentation.
*
See [Include filter](http://loopback.io/doc/en/lb2/Include-filter.html).
* @property {Number} limit Maximum number of instances to return.
*
See [Limit filter](http://loopback.io/doc/en/lb2/Limit-filter.html).
* @property {String} order Sort order: either "ASC" for ascending or "DESC" for descending.
*
See [Order filter](http://loopback.io/doc/en/lb2/Order-filter.html).
* @property {Number} skip Number of results to skip.
*
See [Skip filter](http://loopback.io/doc/en/lb2/Skip-filter.html).
* @property {Object} where Where clause, like
* ```
* { where: { key: val, key2: {gt: 'val2'}, ...} }
* ```
*
See
* [Where filter](http://loopback.io/doc/en/lb2/Where-filter.html#where-clause-for-queries).
*
* @callback {Function} callback Callback function called with `(err, returned-instances)` arguments. Required.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Array} models Model instances matching the filter, or null if none found.
*/
PersistedModel.find = function find(filter, cb) {
throwNotAttached(this.modelName, 'find');
};
/**
* Find one model instance that matches `filter` specification.
* Same as `find`, but limited to one result;
* Returns object, not collection.
*
* @options {Object} [filter] Optional Filter JSON object; see below.
* @property {String|Object|Array} fields Identify fields to include in return result.
*
See [Fields filter](http://loopback.io/doc/en/lb2/Fields-filter.html).
* @property {String|Object|Array} include See PersistedModel.include documentation.
*
See [Include filter](http://loopback.io/doc/en/lb2/Include-filter.html).
* @property {String} order Sort order: either "ASC" for ascending or "DESC" for descending.
*
See [Order filter](http://loopback.io/doc/en/lb2/Order-filter.html).
* @property {Number} skip Number of results to skip.
*
See [Skip filter](http://loopback.io/doc/en/lb2/Skip-filter.html).
* @property {Object} where Where clause, like
* ```
* {where: { key: val, key2: {gt: 'val2'}, ...} }
* ```
*
See
* [Where filter](http://loopback.io/doc/en/lb2/Where-filter.html#where-clause-for-queries).
*
* @callback {Function} callback Callback function called with `(err, returned-instance)` arguments. Required.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Array} model First model instance that matches the filter or null if none found.
*/
PersistedModel.findOne = function findOne(filter, cb) {
throwNotAttached(this.modelName, 'findOne');
};
/**
* Destroy all model instances that match the optional `where` specification.
*
* @param {Object} [where] Optional where filter, like:
* ```
* {key: val, key2: {gt: 'val2'}, ...}
* ```
*
See
* [Where filter](http://loopback.io/doc/en/lb2/Where-filter.html#where-clause-for-other-methods).
*
* @callback {Function} callback Optional callback function called with `(err, info)` arguments.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Object} info Additional information about the command outcome.
* @param {Number} info.count Number of instances (rows, documents) destroyed.
*/
PersistedModel.destroyAll = function destroyAll(where, cb) {
throwNotAttached(this.modelName, 'destroyAll');
};
/**
* Alias for `destroyAll`
*/
PersistedModel.remove = PersistedModel.destroyAll;
/**
* Alias for `destroyAll`
*/
PersistedModel.deleteAll = PersistedModel.destroyAll;
/**
* Update multiple instances that match the where clause.
*
* Example:
*
*```js
* Employee.updateAll({managerId: 'x001'}, {managerId: 'x002'}, function(err, info) {
* ...
* });
* ```
*
* @param {Object} [where] Optional `where` filter, like
* ```
* { key: val, key2: {gt: 'val2'}, ...}
* ```
*
see
* [Where filter](http://loopback.io/doc/en/lb2/Where-filter.html#where-clause-for-other-methods).
* @param {Object} data Object containing data to replace matching instances, if any.
*
* @callback {Function} callback Callback function called with `(err, info)` arguments. Required.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Object} info Additional information about the command outcome.
* @param {Number} info.count Number of instances (rows, documents) updated.
*
*/
PersistedModel.updateAll = function updateAll(where, data, cb) {
throwNotAttached(this.modelName, 'updateAll');
};
/**
* Alias for updateAll.
*/
PersistedModel.update = PersistedModel.updateAll;
/**
* Destroy model instance with the specified ID.
* @param {*} id The ID value of model instance to delete.
* @callback {Function} callback Callback function called with `(err)` arguments. Required.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
*/
PersistedModel.destroyById = function deleteById(id, cb) {
throwNotAttached(this.modelName, 'deleteById');
};
/**
* Alias for destroyById.
*/
PersistedModel.removeById = PersistedModel.destroyById;
/**
* Alias for destroyById.
*/
PersistedModel.deleteById = PersistedModel.destroyById;
/**
* Return the number of records that match the optional "where" filter.
* @param {Object} [where] Optional where filter, like
* ```
* { key: val, key2: {gt: 'val2'}, ...}
* ```
*
See
* [Where filter](http://loopback.io/doc/en/lb2/Where-filter.html#where-clause-for-other-methods).
* @callback {Function} callback Callback function called with `(err, count)` arguments. Required.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Number} count Number of instances.
*/
PersistedModel.count = function(where, cb) {
throwNotAttached(this.modelName, 'count');
};
/**
* Save model instance. If the instance doesn't have an ID, then calls [create](#persistedmodelcreatedata-cb) instead.
* Triggers: validate, save, update, or create.
* @options {Object} [options] See below.
* @property {Boolean} validate Perform validation before saving. Default is true.
* @property {Boolean} throws If true, throw a validation error; WARNING: This can crash Node.
* If false, report the error via callback. Default is false.
* @callback {Function} callback Optional callback function called with `(err, obj)` arguments.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Object} instance Model instance saved or created.
*/
PersistedModel.prototype.save = function(options, callback) {
var Model = this.constructor;
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;
}
var inst = this;
var data = inst.toObject(true);
var id = this.getId();
if (!id) {
return Model.create(this, callback);
}
// validate first
if (!options.validate) {
return save();
}
inst.isValid(function(valid) {
if (valid) {
save();
} else {
var err = new Model.ValidationError(inst);
// throws option is dangerous for async usage
if (options.throws) {
throw err;
}
callback(err, inst);
}
});
// then save
function save() {
inst.trigger('save', function(saveDone) {
inst.trigger('update', function(updateDone) {
Model.upsert(inst, function(err) {
inst._initProperties(data);
updateDone.call(inst, function() {
saveDone.call(inst, function() {
callback(err, inst);
});
});
});
}, data);
}, data);
}
};
/**
* Determine if the data model is new.
* @returns {Boolean} Returns true if the data model is new; false otherwise.
*/
PersistedModel.prototype.isNewRecord = function() {
throwNotAttached(this.constructor.modelName, 'isNewRecord');
};
/**
* Deletes the model from persistence.
* Triggers `destroy` hook (async) before and after destroying object.
* @param {Function} callback Callback function.
*/
PersistedModel.prototype.destroy = function(cb) {
throwNotAttached(this.constructor.modelName, 'destroy');
};
/**
* Alias for destroy.
* @header PersistedModel.remove
*/
PersistedModel.prototype.remove = PersistedModel.prototype.destroy;
/**
* Alias for destroy.
* @header PersistedModel.delete
*/
PersistedModel.prototype.delete = PersistedModel.prototype.destroy;
PersistedModel.prototype.destroy._delegate = true;
/**
* Update a single attribute.
* Equivalent to `updateAttributes({name: 'value'}, cb)`
*
* @param {String} name Name of property.
* @param {Mixed} value Value of property.
* @callback {Function} callback Callback function called with `(err, instance)` arguments. Required.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Object} instance Updated instance.
*/
PersistedModel.prototype.updateAttribute = function updateAttribute(name, value, callback) {
throwNotAttached(this.constructor.modelName, 'updateAttribute');
};
/**
* Update set of attributes. Performs validation before updating.
*
* Triggers: `validation`, `save` and `update` hooks
* @param {Object} data Data to update.
* @callback {Function} callback Callback function called with `(err, instance)` arguments. Required.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Object} instance Updated instance.
*/
PersistedModel.prototype.updateAttributes = PersistedModel.prototype.patchAttributes =
function updateAttributes(data, cb) {
throwNotAttached(this.modelName, 'updateAttributes');
};
/**
* Replace attributes for a model instance and persist it into the datasource.
* Performs validation before replacing.
*
* @param {Object} data Data to replace.
* @options {Object} [options] Options for replace
* @property {Boolean} validate Perform validation before saving. Default is true.
* @callback {Function} callback Callback function called with `(err, instance)` arguments.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Object} instance Replaced instance.
*/
PersistedModel.prototype.replaceAttributes = function replaceAttributes(data, cb) {
throwNotAttached(this.modelName, 'replaceAttributes');
};
/**
* Replace attributes for a model instance whose id is the first input
* argument and persist it into the datasource.
* Performs validation before replacing.
*
* @param {*} id The ID value of model instance to replace.
* @param {Object} data Data to replace.
* @options {Object} [options] Options for replace
* @property {Boolean} validate Perform validation before saving. Default is true.
* @callback {Function} callback Callback function called with `(err, instance)` arguments.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Object} instance Replaced instance.
*/
PersistedModel.replaceById = function replaceById(id, data, cb) {
throwNotAttached(this.modelName, 'replaceById');
};
/**
* Reload object from persistence. Requires `id` member of `object` to be able to call `find`.
* @callback {Function} callback Callback function called with `(err, instance)` arguments. Required.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Object} instance Model instance.
*/
PersistedModel.prototype.reload = function reload(callback) {
throwNotAttached(this.constructor.modelName, 'reload');
};
/**
* Set the correct `id` property for the `PersistedModel`. Uses the `setId` method if the model is attached to
* connector that defines it. Otherwise, uses the default lookup.
* Override this method to handle complex IDs.
*
* @param {*} val The `id` value. Will be converted to the type that the `id` property specifies.
*/
PersistedModel.prototype.setId = function(val) {
var ds = this.getDataSource();
this[this.getIdName()] = val;
};
/**
* Get the `id` value for the `PersistedModel`.
*
* @returns {*} The `id` value
*/
PersistedModel.prototype.getId = function() {
var data = this.toObject();
if (!data) return;
return data[this.getIdName()];
};
/**
* Get the `id` property name of the constructor.
*
* @returns {String} The `id` property name
*/
PersistedModel.prototype.getIdName = function() {
return this.constructor.getIdName();
};
/**
* Get the `id` property name of the constructor.
*
* @returns {String} The `id` property name
*/
PersistedModel.getIdName = function() {
var Model = this;
var ds = Model.getDataSource();
if (ds.idName) {
return ds.idName(Model.modelName);
} else {
return 'id';
}
};
PersistedModel.setupRemoting = function() {
var PersistedModel = this;
var typeName = PersistedModel.modelName;
var options = PersistedModel.settings;
// if there is atleast one updateOnly property, then we set
// createOnlyInstance flag in __create__ to indicate loopback-swagger
// code to create a separate model instance for create operation only
const updateOnlyProps = this.getUpdateOnlyProperties ?
this.getUpdateOnlyProperties() : false;
const hasUpdateOnlyProps = updateOnlyProps && updateOnlyProps.length > 0;
// This is just for LB 3.x
options.replaceOnPUT = options.replaceOnPUT !== false;
function setRemoting(scope, name, options) {
var fn = scope[name];
fn._delegate = true;
options.isStatic = scope === PersistedModel;
PersistedModel.remoteMethod(name, options);
}
setRemoting(PersistedModel, 'create', {
description: 'Create a new instance of the model and persist it into the data source.',
accessType: 'WRITE',
accepts: [
{
arg: 'data', type: 'object', model: typeName, allowArray: true,
createOnlyInstance: hasUpdateOnlyProps,
description: 'Model instance data',
http: {source: 'body'},
},
{arg: 'options', type: 'object', http: 'optionsFromRequest'},
],
returns: {arg: 'data', type: typeName, root: true},
http: {verb: 'post', path: '/'},
});
var upsertOptions = {
aliases: ['upsert', 'updateOrCreate'],
description: 'Patch an existing model instance or insert a new one ' +
'into the data source.',
accessType: 'WRITE',
accepts: [
{
arg: 'data', type: 'object', model: typeName, http: {source: 'body'},
description: 'Model instance data',
},
{arg: 'options', type: 'object', http: 'optionsFromRequest'},
],
returns: {arg: 'data', type: typeName, root: true},
http: [{verb: 'patch', path: '/'}],
};
if (!options.replaceOnPUT) {
upsertOptions.http.unshift({verb: 'put', path: '/'});
}
setRemoting(PersistedModel, 'patchOrCreate', upsertOptions);
var replaceOrCreateOptions = {
description: 'Replace an existing model instance or insert a new one into the data source.',
accessType: 'WRITE',
accepts: [
{
arg: 'data', type: 'object', model: typeName,
http: {source: 'body'},
description: 'Model instance data',
},
{arg: 'options', type: 'object', http: 'optionsFromRequest'},
],
returns: {arg: 'data', type: typeName, root: true},
http: [{verb: 'post', path: '/replaceOrCreate'}],
};
if (options.replaceOnPUT) {
replaceOrCreateOptions.http.push({verb: 'put', path: '/'});
}
setRemoting(PersistedModel, 'replaceOrCreate', replaceOrCreateOptions);
setRemoting(PersistedModel, 'upsertWithWhere', {
aliases: ['patchOrCreateWithWhere'],
description: 'Update an existing model instance or insert a new one into ' +
'the data source based on the where criteria.',
accessType: 'WRITE',
accepts: [
{arg: 'where', type: 'object', http: {source: 'query'},
description: 'Criteria to match model instances'},
{arg: 'data', type: 'object', model: typeName, http: {source: 'body'},
description: 'An object of model property name/value pairs'},
{arg: 'options', type: 'object', http: 'optionsFromRequest'},
],
returns: {arg: 'data', type: typeName, root: true},
http: {verb: 'post', path: '/upsertWithWhere'},
});
setRemoting(PersistedModel, 'exists', {
description: 'Check whether a model instance exists in the data source.',
accessType: 'READ',
accepts: [
{arg: 'id', type: 'any', description: 'Model id', required: true},
{arg: 'options', type: 'object', http: 'optionsFromRequest'},
],
returns: {arg: 'exists', type: 'boolean'},
http: [
{verb: 'get', path: '/:id/exists'},
{verb: 'head', path: '/:id'},
],
rest: {
// After hook to map exists to 200/404 for HEAD
after: function(ctx, cb) {
if (ctx.req.method === 'GET') {
// For GET, return {exists: true|false} as is
return cb();
}
if (!ctx.result.exists) {
var modelName = ctx.method.sharedClass.name;
var id = ctx.getArgByName('id');
var msg = 'Unknown "' + modelName + '" id "' + id + '".';
var error = new Error(msg);
error.statusCode = error.status = 404;
error.code = 'MODEL_NOT_FOUND';
cb(error);
} else {
cb();
}
},
},
});
setRemoting(PersistedModel, 'findById', {
description: 'Find a model instance by {{id}} from the data source.',
accessType: 'READ',
accepts: [
{arg: 'id', type: 'any', description: 'Model id', required: true,
http: {source: 'path'}},
{arg: 'filter', type: 'object',
description:
'Filter defining fields and include - must be a JSON-encoded string (' +
'{"something":"value"})'},
{arg: 'options', type: 'object', http: 'optionsFromRequest'},
],
returns: {arg: 'data', type: typeName, root: true},
http: {verb: 'get', path: '/:id'},
rest: {after: convertNullToNotFoundError},
});
var replaceByIdOptions = {
description: 'Replace attributes for a model instance and persist it into the data source.',
accessType: 'WRITE',
accepts: [
{arg: 'id', type: 'any', description: 'Model id', required: true,
http: {source: 'path'}},
{arg: 'data', type: 'object', model: typeName, http: {source: 'body'}, description:
'Model instance data'},
{arg: 'options', type: 'object', http: 'optionsFromRequest'},
],
returns: {arg: 'data', type: typeName, root: true},
http: [{verb: 'post', path: '/:id/replace'}],
};
if (options.replaceOnPUT) {
replaceByIdOptions.http.push({verb: 'put', path: '/:id'});
}
setRemoting(PersistedModel, 'replaceById', replaceByIdOptions);
setRemoting(PersistedModel, 'find', {
description: 'Find all instances of the model matched by filter from the data source.',
accessType: 'READ',
accepts: [
{arg: 'filter', type: 'object', description:
'Filter defining fields, where, include, order, offset, and limit - must be a ' +
'JSON-encoded string ({"something":"value"})'},
{arg: 'options', type: 'object', http: 'optionsFromRequest'},
],
returns: {arg: 'data', type: [typeName], root: true},
http: {verb: 'get', path: '/'},
});
setRemoting(PersistedModel, 'findOne', {
description: 'Find first instance of the model matched by filter from the data source.',
accessType: 'READ',
accepts: [
{arg: 'filter', type: 'object', description:
'Filter defining fields, where, include, order, offset, and limit - must be a ' +
'JSON-encoded string ({"something":"value"})'},
{arg: 'options', type: 'object', http: 'optionsFromRequest'},
],
returns: {arg: 'data', type: typeName, root: true},
http: {verb: 'get', path: '/findOne'},
rest: {after: convertNullToNotFoundError},
});
setRemoting(PersistedModel, 'destroyAll', {
description: 'Delete all matching records.',
accessType: 'WRITE',
accepts: [
{arg: 'where', type: 'object', description: 'filter.where object'},
{arg: 'options', type: 'object', http: 'optionsFromRequest'},
],
returns: {
arg: 'count',
type: 'object',
description: 'The number of instances deleted',
root: true,
},
http: {verb: 'del', path: '/'},
shared: false,
});
setRemoting(PersistedModel, 'updateAll', {
aliases: ['update'],
description: 'Update instances of the model matched by {{where}} from the data source.',
accessType: 'WRITE',
accepts: [
{arg: 'where', type: 'object', http: {source: 'query'},
description: 'Criteria to match model instances'},
{arg: 'data', type: 'object', model: typeName, http: {source: 'body'},
description: 'An object of model property name/value pairs'},
{arg: 'options', type: 'object', http: 'optionsFromRequest'},
],
returns: {
arg: 'info',
description: 'Information related to the outcome of the operation',
type: {
count: {
type: 'number',
description: 'The number of instances updated',
},
},
root: true,
},
http: {verb: 'post', path: '/update'},
});
setRemoting(PersistedModel, 'deleteById', {
aliases: ['destroyById', 'removeById'],
description: 'Delete a model instance by {{id}} from the data source.',
accessType: 'WRITE',
accepts: [
{arg: 'id', type: 'any', description: 'Model id', required: true,
http: {source: 'path'}},
{arg: 'options', type: 'object', http: 'optionsFromRequest'},
],
http: {verb: 'del', path: '/:id'},
returns: {arg: 'count', type: 'object', root: true},
});
setRemoting(PersistedModel, 'count', {
description: 'Count instances of the model matched by where from the data source.',
accessType: 'READ',
accepts: [
{arg: 'where', type: 'object', description: 'Criteria to match model instances'},
{arg: 'options', type: 'object', http: 'optionsFromRequest'},
],
returns: {arg: 'count', type: 'number'},
http: {verb: 'get', path: '/count'},
});
var updateAttributesOptions = {
aliases: ['updateAttributes'],
description: 'Patch attributes for a model instance and persist it into ' +
'the data source.',
accessType: 'WRITE',
accepts: [
{
arg: 'data', type: 'object', model: typeName,
http: {source: 'body'},
description: 'An object of model property name/value pairs',
},
{arg: 'options', type: 'object', http: 'optionsFromRequest'},
],
returns: {arg: 'data', type: typeName, root: true},
http: [{verb: 'patch', path: '/'}],
};
setRemoting(PersistedModel.prototype, 'patchAttributes', updateAttributesOptions);
if (!options.replaceOnPUT) {
updateAttributesOptions.http.unshift({verb: 'put', path: '/'});
}
if (options.trackChanges || options.enableRemoteReplication) {
setRemoting(PersistedModel, 'diff', {
description: 'Get a set of deltas and conflicts since the given checkpoint.',
accessType: 'READ',
accepts: [
{arg: 'since', type: 'number', description: 'Find deltas since this checkpoint'},
{arg: 'remoteChanges', type: 'array', description: 'an array of change objects',
http: {source: 'body'}},
],
returns: {arg: 'result', type: 'object', root: true},
http: {verb: 'post', path: '/diff'},
});
setRemoting(PersistedModel, 'changes', {
description: 'Get the changes to a model since a given checkpoint.' +
'Provide a filter object to reduce the number of results returned.',
accessType: 'READ',
accepts: [
{arg: 'since', type: 'number', description:
'Only return changes since this checkpoint'},
{arg: 'filter', type: 'object', description:
'Only include changes that match this filter'},
],
returns: {arg: 'changes', type: 'array', root: true},
http: {verb: 'get', path: '/changes'},
});
setRemoting(PersistedModel, 'checkpoint', {
description: 'Create a checkpoint.',
// The replication algorithm needs to create a source checkpoint,
// even though it is otherwise not making any source changes.
// We need to allow this method for users that don't have full
// WRITE permissions.
accessType: 'REPLICATE',
returns: {arg: 'checkpoint', type: 'object', root: true},
http: {verb: 'post', path: '/checkpoint'},
});
setRemoting(PersistedModel, 'currentCheckpoint', {
description: 'Get the current checkpoint.',
accessType: 'READ',
returns: {arg: 'checkpoint', type: 'object', root: true},
http: {verb: 'get', path: '/checkpoint'},
});
setRemoting(PersistedModel, 'createUpdates', {
description: 'Create an update list from a delta list.',
// This operation is read-only, it does not change any local data.
// It is called by the replication algorithm to compile a list
// of changes to apply on the target.
accessType: 'READ',
accepts: {arg: 'deltas', type: 'array', http: {source: 'body'}},
returns: {arg: 'updates', type: 'array', root: true},
http: {verb: 'post', path: '/create-updates'},
});
setRemoting(PersistedModel, 'bulkUpdate', {
description: 'Run multiple updates at once. Note: this is not atomic.',
accessType: 'WRITE',
accepts: {arg: 'updates', type: 'array'},
http: {verb: 'post', path: '/bulk-update'},
});
setRemoting(PersistedModel, 'findLastChange', {
description: 'Get the most recent change record for this instance.',
accessType: 'READ',
accepts: {
arg: 'id', type: 'any', required: true, http: {source: 'path'},
description: 'Model id',
},
returns: {arg: 'result', type: this.Change.modelName, root: true},
http: {verb: 'get', path: '/:id/changes/last'},
});
setRemoting(PersistedModel, 'updateLastChange', {
description:
'Update the properties of the most recent change record ' +
'kept for this instance.',
accessType: 'WRITE',
accepts: [
{
arg: 'id', type: 'any', required: true, http: {source: 'path'},
description: 'Model id',
},
{
arg: 'data', type: 'object', model: typeName, http: {source: 'body'},
description: 'An object of Change property name/value pairs',
},
],
returns: {arg: 'result', type: this.Change.modelName, root: true},
http: {verb: 'put', path: '/:id/changes/last'},
});
}
setRemoting(PersistedModel, 'createChangeStream', {
description: 'Create a change stream.',
accessType: 'READ',
http: [
{verb: 'post', path: '/change-stream'},
{verb: 'get', path: '/change-stream'},
],
accepts: {
arg: 'options',
type: 'object',
},
returns: {
arg: 'changes',
type: 'ReadableStream',
json: true,
},
});
};
/**
* Get a set of deltas and conflicts since the given checkpoint.
*
* See [Change.diff()](#change-diff) for details.
*
* @param {Number} since Find deltas since this checkpoint.
* @param {Array} remoteChanges An array of change objects.
* @callback {Function} callback Callback function called with `(err, result)` arguments. Required.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Object} result Object with `deltas` and `conflicts` properties; see [Change.diff()](#change-diff) for details.
*/
PersistedModel.diff = function(since, remoteChanges, callback) {
var Change = this.getChangeModel();
Change.diff(this.modelName, since, remoteChanges, callback);
};
/**
* Get the changes to a model since the specified checkpoint. Provide a filter object
* to reduce the number of results returned.
* @param {Number} since Return only changes since this checkpoint.
* @param {Object} filter Include only changes that match this filter, the same as for [#persistedmodel-find](find()).
* @callback {Function} callback Callback function called with `(err, changes)` arguments. Required.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Array} changes An array of [Change](#change) objects.
*/
PersistedModel.changes = function(since, filter, callback) {
if (typeof since === 'function') {
filter = {};
callback = since;
since = -1;
}
if (typeof filter === 'function') {
callback = filter;
since = -1;
filter = {};
}
var idName = this.dataSource.idName(this.modelName);
var Change = this.getChangeModel();
var model = this;
const changeFilter = this.createChangeFilter(since, filter);
filter = filter || {};
filter.fields = {};
filter.where = filter.where || {};
filter.fields[idName] = true;
// TODO(ritch) this whole thing could be optimized a bit more
Change.find(changeFilter, function(err, changes) {
if (err) return callback(err);
if (!Array.isArray(changes) || changes.length === 0) return callback(null, []);
var ids = changes.map(function(change) {
return change.getModelId();
});
filter.where[idName] = {inq: ids};
model.find(filter, function(err, models) {
if (err) return callback(err);
var modelIds = models.map(function(m) {
return m[idName].toString();
});
callback(null, changes.filter(function(ch) {
if (ch.type() === Change.DELETE) return true;
return modelIds.indexOf(ch.modelId) > -1;
}));
});
});
};
/**
* Create a checkpoint.
*
* @param {Function} callback
*/
PersistedModel.checkpoint = function(cb) {
var Checkpoint = this.getChangeModel().getCheckpointModel();
Checkpoint.bumpLastSeq(cb);
};
/**
* Get the current checkpoint ID.
*
* @callback {Function} callback Callback function called with `(err, currentCheckpointId)` arguments. Required.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Number} currentCheckpointId Current checkpoint ID.
*/
PersistedModel.currentCheckpoint = function(cb) {
var Checkpoint = this.getChangeModel().getCheckpointModel();
Checkpoint.current(cb);
};
/**
* Replicate changes since the given checkpoint to the given target model.
*
* @param {Number} [since] Since this checkpoint
* @param {Model} targetModel Target this model class
* @param {Object} [options] An optional options object to pass to underlying data-access calls.
* @param {Object} [options.filter] Replicate models that match this filter
* @callback {Function} [callback] Callback function called with `(err, conflicts)` arguments.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {Conflict[]} conflicts A list of changes that could not be replicated due to conflicts.
* @param {Object} checkpoints The new checkpoints to use as the "since"
* argument for the next replication.
*
* @promise
*/
PersistedModel.replicate = function(since, targetModel, options, callback) {
var lastArg = arguments[arguments.length - 1];
if (typeof lastArg === 'function' && arguments.length > 1) {
callback = lastArg;
}
if (typeof since === 'function' && since.modelName) {
targetModel = since;
since = -1;
}
if (typeof since !== 'object') {
since = {source: since, target: since};
}
if (typeof options === 'function') {
options = {};
}
options = options || {};
var sourceModel = this;
callback = callback || utils.createPromiseCallback();
debug('replicating %s since %s to %s since %s',
sourceModel.modelName,
since.source,
targetModel.modelName,
since.target);
if (options.filter) {
debug('\twith filter %j', options.filter);
}
// In order to avoid a race condition between the replication and
// other clients modifying the data, we must create the new target
// checkpoint as the first step of the replication process.
// As a side-effect of that, the replicated changes are associated
// with the new target checkpoint. This is actually desired behaviour,
// because that way clients replicating *from* the target model
// since the new checkpoint will pick these changes up.
// However, it increases the likelihood of (false) conflicts being detected.
// In order to prevent that, we run the replication multiple times,
// until no changes were replicated, but at most MAX_ATTEMPTS times
// to prevent starvation. In most cases, the second run will find no changes
// to replicate and we are done.
var MAX_ATTEMPTS = 3;
run(1, since);
return callback.promise;
function run(attempt, since) {
debug('\titeration #%s', attempt);
tryReplicate(sourceModel, targetModel, since, options, next);
function next(err, conflicts, cps, updates) {
var finished = err || conflicts.length ||
!updates || updates.length === 0 ||
attempt >= MAX_ATTEMPTS;
if (finished)
return callback(err, conflicts, cps);
run(attempt + 1, cps);
}
}
};
function tryReplicate(sourceModel, targetModel, since, options, callback) {
var Change = sourceModel.getChangeModel();
var TargetChange = targetModel.getChangeModel();
var changeTrackingEnabled = Change && TargetChange;
var replicationChunkSize = REPLICATION_CHUNK_SIZE;
if (sourceModel.settings && sourceModel.settings.replicationChunkSize) {
replicationChunkSize = sourceModel.settings.replicationChunkSize;
}
assert(
changeTrackingEnabled,
'You must enable change tracking before replicating'
);
var diff, updates, newSourceCp, newTargetCp;
var tasks = [
checkpoints,
getSourceChanges,
getDiffFromTarget,
createSourceUpdates,
bulkUpdate,
];
async.waterfall(tasks, done);
function getSourceChanges(cb) {
utils.downloadInChunks(
options.filter,
replicationChunkSize,
function(filter, pagingCallback) {
sourceModel.changes(since.source, filter, pagingCallback);
},
debug.enabled ? log : cb);
function log(err, result) {
if (err) return cb(err);
debug('\tusing source changes');
result.forEach(function(it) { debug('\t\t%j', it); });
cb(err, result);
}
}
function getDiffFromTarget(sourceChanges, cb) {
utils.uploadInChunks(
sourceChanges,
replicationChunkSize,
function(smallArray, chunkCallback) {
return targetModel.diff(since.target, smallArray, chunkCallback);
},
debug.enabled ? log : cb);
function log(err, result) {
if (err) return cb(err);
if (result.conflicts && result.conflicts.length) {
debug('\tdiff conflicts');
result.conflicts.forEach(function(d) { debug('\t\t%j', d); });
}
if (result.deltas && result.deltas.length) {
debug('\tdiff deltas');
result.deltas.forEach(function(it) { debug('\t\t%j', it); });
}
cb(err, result);
}
}
function createSourceUpdates(_diff, cb) {
diff = _diff;
diff.conflicts = diff.conflicts || [];
if (diff && diff.deltas && diff.deltas.length) {
debug('\tbuilding a list of updates');
utils.uploadInChunks(
diff.deltas,
replicationChunkSize,
function(smallArray, chunkCallback) {
return sourceModel.createUpdates(smallArray, chunkCallback);
},
cb);
} else {
// nothing to replicate
done();
}
}
function bulkUpdate(_updates, cb) {
debug('\tstarting bulk update');
updates = _updates;
utils.uploadInChunks(
updates,
replicationChunkSize,
function(smallArray, chunkCallback) {
return targetModel.bulkUpdate(smallArray, options, function(err) {
// bulk update is a special case where we want to process all chunks and aggregate all errors
chunkCallback(null, err);
});
},
function(notUsed, err) {
var conflicts = err && err.details && err.details.conflicts;
if (conflicts && err.statusCode == 409) {
diff.conflicts = conflicts;
// filter out updates that were not applied
updates = updates.filter(function(u) {
return conflicts
.filter(function(d) { return d.modelId === u.change.modelId; })
.length === 0;
});
return cb();
}
cb(err);
});
}
function checkpoints() {
var cb = arguments[arguments.length - 1];
sourceModel.checkpoint(function(err, source) {
if (err) return cb(err);
newSourceCp = source.seq;
targetModel.checkpoint(function(err, target) {
if (err) return cb(err);
newTargetCp = target.seq;
debug('\tcreated checkpoints');
debug('\t\t%s for source model %s', newSourceCp, sourceModel.modelName);
debug('\t\t%s for target model %s', newTargetCp, targetModel.modelName);
cb();
});
});
}
function done(err) {
if (err) return callback(err);
debug('\treplication finished');
debug('\t\t%s conflict(s) detected', diff.conflicts.length);
debug('\t\t%s change(s) applied', updates ? updates.length : 0);
debug('\t\tnew checkpoints: { source: %j, target: %j }',
newSourceCp, newTargetCp);
var conflicts = diff.conflicts.map(function(change) {
return new Change.Conflict(
change.modelId, sourceModel, targetModel
);
});
if (conflicts.length) {
sourceModel.emit('conflicts', conflicts);
}
if (callback) {
var newCheckpoints = {source: newSourceCp, target: newTargetCp};
callback(null, conflicts, newCheckpoints, updates);
}
}
}
/**
* Create an update list (for `Model.bulkUpdate()`) from a delta list
* (result of `Change.diff()`).
*
* @param {Array} deltas
* @param {Function} callback
*/
PersistedModel.createUpdates = function(deltas, cb) {
var Change = this.getChangeModel();
var updates = [];
var Model = this;
var tasks = [];
deltas.forEach(function(change) {
change = new Change(change);
var type = change.type();
var update = {type: type, change: change};
switch (type) {
case Change.CREATE:
case Change.UPDATE:
tasks.push(function(cb) {
Model.findById(change.modelId, function(err, inst) {
if (err) return cb(err);
if (!inst) {
return cb &&
cb(new Error(g.f('Missing data for change: %s', change.modelId)));
}
if (inst.toObject) {
update.data = inst.toObject();
} else {
update.data = inst;
}
updates.push(update);
cb();
});
});
break;
case Change.DELETE:
updates.push(update);
break;
}
});
async.parallel(tasks, function(err) {
if (err) return cb(err);
cb(null, updates);
});
};
/**
* Apply an update list.
*
* **Note: this is not atomic**
*
* @param {Array} updates An updates list, usually from [createUpdates()](#persistedmodel-createupdates).
* @param {Object} [options] An optional options object to pass to underlying data-access calls.
* @param {Function} callback Callback function.
*/
PersistedModel.bulkUpdate = function(updates, options, callback) {
var tasks = [];
var Model = this;
var Change = this.getChangeModel();
var conflicts = [];
var lastArg = arguments[arguments.length - 1];
if (typeof lastArg === 'function' && arguments.length > 1) {
callback = lastArg;
}
if (typeof options === 'function') {
options = {};
}
options = options || {};
buildLookupOfAffectedModelData(Model, updates, function(err, currentMap) {
if (err) return callback(err);
updates.forEach(function(update) {
var id = update.change.modelId;
var current = currentMap[id];
switch (update.type) {
case Change.UPDATE:
tasks.push(function(cb) {
applyUpdate(Model, id, current, update.data, update.change, conflicts, options, cb);
});
break;
case Change.CREATE:
tasks.push(function(cb) {
applyCreate(Model, id, current, update.data, update.change, conflicts, options, cb);
});
break;
case Change.DELETE:
tasks.push(function(cb) {
applyDelete(Model, id, current, update.change, conflicts, options, cb);
});
break;
}
});
async.parallel(tasks, function(err) {
if (err) return callback(err);
if (conflicts.length) {
err = new Error(g.f('Conflict'));
err.statusCode = 409;
err.details = {conflicts: conflicts};
return callback(err);
}
callback();
});
});
};
function buildLookupOfAffectedModelData(Model, updates, callback) {
var idName = Model.dataSource.idName(Model.modelName);
var affectedIds = updates.map(function(u) { return u.change.modelId; });
var whereAffected = {};
whereAffected[idName] = {inq: affectedIds};
Model.find({where: whereAffected}, function(err, affectedList) {
if (err) return callback(err);
var dataLookup = {};
affectedList.forEach(function(it) {
dataLookup[it[idName]] = it;
});
callback(null, dataLookup);
});
}
function applyUpdate(Model, id, current, data, change, conflicts, options, cb) {
var Change = Model.getChangeModel();
var rev = current ? Change.revisionForInst(current) : null;
if (rev !== change.prev) {
debug('Detected non-rectified change of %s %j',
Model.modelName, id);
debug('\tExpected revision: %s', change.rev);
debug('\tActual revision: %s', rev);
conflicts.push(change);
return Change.rectifyModelChanges(Model.modelName, [id], cb);
}
// TODO(bajtos) modify `data` so that it instructs
// the connector to remove any properties included in "inst"
// but not included in `data`
// See https://github.com/strongloop/loopback/issues/1215
Model.updateAll(current.toObject(), data, options, function(err, result) {
if (err) return cb(err);
var count = result && result.count;
switch (count) {
case 1:
// The happy path, exactly one record was updated
return cb();
case 0:
debug('UpdateAll detected non-rectified change of %s %j',
Model.modelName, id);
conflicts.push(change);
// NOTE(bajtos) updateAll triggers change rectification
// for all model instances, even when no records were updated,
// thus we don't need to rectify explicitly ourselves
return cb();
case undefined:
case null:
return cb(new Error(
g.f('Cannot apply bulk updates, ' +
'the connector does not correctly report ' +
'the number of updated records.')));
default:
debug('%s.updateAll modified unexpected number of instances: %j',
Model.modelName, count);
return cb(new Error(
g.f('Bulk update failed, the connector has modified unexpected ' +
'number of records: %s', JSON.stringify(count))));
}
});
}
function applyCreate(Model, id, current, data, change, conflicts, options, cb) {
Model.create(data, options, function(createErr) {
if (!createErr) return cb();
// We don't have a reliable way how to detect the situation
// where he model was not create because of a duplicate id
// The workaround is to query the DB to check if the model already exists
Model.findById(id, function(findErr, inst) {
if (findErr || !inst) {
// There isn't any instance with the same id, thus there isn't
// any conflict and we just report back the original error.
return cb(createErr);
}
return conflict();
});
});
function conflict() {
// The instance already exists - report a conflict
debug('Detected non-rectified new instance of %s %j',
Model.modelName, id);
conflicts.push(change);
var Change = Model.getChangeModel();
return Change.rectifyModelChanges(Model.modelName, [id], cb);
}
}
function applyDelete(Model, id, current, change, conflicts, options, cb) {
if (!current) {
// The instance was either already deleted or not created at all,
// we are done.
return cb();
}
var Change = Model.getChangeModel();
var rev = Change.revisionForInst(current);
if (rev !== change.prev) {
debug('Detected non-rectified change of %s %j',
Model.modelName, id);
debug('\tExpected revision: %s', change.rev);
debug('\tActual revision: %s', rev);
conflicts.push(change);
return Change.rectifyModelChanges(Model.modelName, [id], cb);
}
Model.deleteAll(current.toObject(), options, function(err, result) {
if (err) return cb(err);
var count = result && result.count;
switch (count) {
case 1:
// The happy path, exactly one record was updated
return cb();
case 0:
debug('DeleteAll detected non-rectified change of %s %j',
Model.modelName, id);
conflicts.push(change);
// NOTE(bajtos) deleteAll triggers change rectification
// for all model instances, even when no records were updated,
// thus we don't need to rectify explicitly ourselves
return cb();
case undefined:
case null:
return cb(new Error(
g.f('Cannot apply bulk updates, ' +
'the connector does not correctly report ' +
'the number of deleted records.')));
default:
debug('%s.deleteAll modified unexpected number of instances: %j',
Model.modelName, count);
return cb(new Error(
g.f('Bulk update failed, the connector has deleted unexpected ' +
'number of records: %s', JSON.stringify(count))));
}
});
}
/**
* Get the `Change` model.
* Throws an error if the change model is not correctly setup.
* @return {Change}
*/
PersistedModel.getChangeModel = function() {
var changeModel = this.Change;
var isSetup = changeModel && changeModel.dataSource;
assert(isSetup, 'Cannot get a setup Change model for ' + this.modelName);
return changeModel;
};
/**
* Get the source identifier for this model or dataSource.
*
* @callback {Function} callback Callback function called with `(err, id)` arguments.
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
* @param {String} sourceId Source identifier for the model or dataSource.
*/
PersistedModel.getSourceId = function(cb) {
var dataSource = this.dataSource;
if (!dataSource) {
this.once('dataSourceAttached', this.getSourceId.bind(this, cb));
}
assert(
dataSource.connector.name,
'Model.getSourceId: cannot get id without dataSource.connector.name'
);
var id = [dataSource.connector.name, this.modelName].join('-');
cb(null, id);
};
/**
* Enable the tracking of changes made to the model. Usually for replication.
*/
PersistedModel.enableChangeTracking = function() {
var Model = this;
var Change = this.Change || this._defineChangeModel();
var cleanupInterval = Model.settings.changeCleanupInterval || 30000;
assert(this.dataSource, 'Cannot enableChangeTracking(): ' + this.modelName +
' is not attached to a dataSource');
var idName = this.getIdName();
var idProp = this.definition.properties[idName];
var idType = idProp && idProp.type;
var idDefn = idProp && idProp.defaultFn;
if (idType !== String || !(idDefn === 'uuid' || idDefn === 'guid')) {
deprecated('The model ' + this.modelName + ' is tracking changes, ' +
'which requires a string id with GUID/UUID default value.');
}
Model.observe('after save', rectifyOnSave);
Model.observe('after delete', rectifyOnDelete);
// Only run if the run time is server
// Can switch off cleanup by setting the interval to -1
if (runtime.isServer && cleanupInterval > 0) {
// initial cleanup
cleanup();
// cleanup
setInterval(cleanup, cleanupInterval);
}
function cleanup() {
Model.rectifyAllChanges(function(err) {
if (err) {
Model.handleChangeError(err, 'cleanup');
}
});
}
};
function rectifyOnSave(ctx, next) {
var instance = ctx.instance || ctx.currentInstance;
var id = instance ? instance.getId() :
getIdFromWhereByModelId(ctx.Model, ctx.where);
if (debug.enabled) {
debug('rectifyOnSave %s -> ' + (id ? 'id %j' : '%s'),
ctx.Model.modelName, id ? id : 'ALL');
debug('context instance:%j currentInstance:%j where:%j data %j',
ctx.instance, ctx.currentInstance, ctx.where, ctx.data);
}
if (id) {
ctx.Model.rectifyChange(id, reportErrorAndNext);
} else {
ctx.Model.rectifyAllChanges(reportErrorAndNext);
}
function reportErrorAndNext(err) {
if (err) {
ctx.Model.handleChangeError(err, 'after save');
}
next();
}
}
function rectifyOnDelete(ctx, next) {
var id = ctx.instance ? ctx.instance.getId() :
getIdFromWhereByModelId(ctx.Model, ctx.where);
if (debug.enabled) {
debug('rectifyOnDelete %s -> ' + (id ? 'id %j' : '%s'),
ctx.Model.modelName, id ? id : 'ALL');
debug('context instance:%j where:%j', ctx.instance, ctx.where);
}
if (id) {
ctx.Model.rectifyChange(id, reportErrorAndNext);
} else {
ctx.Model.rectifyAllChanges(reportErrorAndNext);
}
function reportErrorAndNext(err) {
if (err) {
ctx.Model.handleChangeError(err, 'after delete');
}
next();
}
}
function getIdFromWhereByModelId(Model, where) {
var idName = Model.getIdName();
if (!(idName in where)) return undefined;
var id = where[idName];
// TODO(bajtos) support object values that are not LB conditions
if (typeof id === 'string' || typeof id === 'number') {
return id;
}
return undefined;
}
PersistedModel._defineChangeModel = function() {
var BaseChangeModel = this.registry.getModel('Change');
assert(BaseChangeModel,
'Change model must be defined before enabling change replication');
const additionalChangeModelProperties =
this.settings.additionalChangeModelProperties || {};
this.Change = BaseChangeModel.extend(this.modelName + '-change',
additionalChangeModelProperties,
{trackModel: this}
);
if (this.dataSource) {
attachRelatedModels(this);
}
// Re-attach related models whenever our datasource is changed.
var self = this;
this.on('dataSourceAttached', function() {
attachRelatedModels(self);
});
return this.Change;
function attachRelatedModels(self) {
self.Change.attachTo(self.dataSource);
self.Change.getCheckpointModel().attachTo(self.dataSource);
}
};
PersistedModel.rectifyAllChanges = function(callback) {
this.getChangeModel().rectifyAll(callback);
};
/**
* Handle a change error. Override this method in a subclassing model to customize
* change error handling.
*
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb2/Error-object.html).
*/
PersistedModel.handleChangeError = function(err, operationName) {
if (!err) return;
this.emit('error', err, operationName);
};
/**
* Specify that a change to the model with the given ID has occurred.
*
* @param {*} id The ID of the model that has changed.
* @callback {Function} callback
* @param {Error} err
*/
PersistedModel.rectifyChange = function(id, callback) {
var Change = this.getChangeModel();
Change.rectifyModelChanges(this.modelName, [id], callback);
};
PersistedModel.findLastChange = function(id, cb) {
var Change = this.getChangeModel();
Change.findOne({where: {modelId: id}}, cb);
};
PersistedModel.updateLastChange = function(id, data, cb) {
var self = this;
this.findLastChange(id, function(err, inst) {
if (err) return cb(err);
if (!inst) {
err = new Error(g.f('No change record found for %s with id %s',
self.modelName, id));
err.statusCode = 404;
return cb(err);
}
inst.updateAttributes(data, cb);
});
};
/**
* Create a change stream. [See here for more info](http://loopback.io/doc/en/lb2/Realtime-server-sent-events.html)
*
* @param {Object} options
* @param {Object} options.where Only changes to models matching this where filter will be included in the `ChangeStream`.
* @callback {Function} callback
* @param {Error} err
* @param {ChangeStream} changes
*/
PersistedModel.createChangeStream = function(options, cb) {
if (typeof options === 'function') {
cb = options;
options = undefined;
}
var idName = this.getIdName();
var Model = this;
var changes = new PassThrough({objectMode: true});
changes._destroy = function() {
changes.end();
changes.emit('end');
changes.emit('close');
};
changes.destroy = changes.destroy || changes._destroy; // node 8 compability
changes.on('error', removeHandlers);
changes.on('close', removeHandlers);
changes.on('finish', removeHandlers);
changes.on('end', removeHandlers);
process.nextTick(function() {
cb(null, changes);
});
Model.observe('after save', changeHandler);
Model.observe('after delete', deleteHandler);
function changeHandler(ctx, next) {
var change = createChangeObject(ctx, 'save');
changes.write(change);
next();
};
function deleteHandler(ctx, next) {
var change = createChangeObject(ctx, 'delete');
changes.write(change);
next();
};
function createChangeObject(ctx, type) {
var where = ctx.where;
var data = ctx.instance || ctx.data;
var whereId = where && where[idName];
// the data includes the id
// or the where includes the id
var target;
if (data && (data[idName] || data[idName] === 0)) {
target = data[idName];
} else if (where && (where[idName] || where[idName] === 0)) {
target = where[idName];
}
var hasTarget = target === 0 || !!target;
var change = {
target: target,
where: where,
data: data,
};
switch (type) {
case 'save':
if (ctx.isNewInstance === undefined) {
change.type = hasTarget ? 'update' : 'create';
} else {
change.type = ctx.isNewInstance ? 'create' : 'update';
}
break;
case 'delete':
change.type = 'remove';
break;
}
return change;
}
function removeHandlers() {
Model.removeObserver('after save', changeHandler);
Model.removeObserver('after delete', deleteHandler);
}
};
/**
* Get the filter for searching related changes.
*
* Models should override this function to copy properties
* from the model instance filter into the change search filter.
*
* ```js
* module.exports = (TargetModel, config) => {
* TargetModel.createChangeFilter = function(since, modelFilter) {
* const filter = this.base.createChangeFilter.apply(this, arguments);
* if (modelFilter && modelFilter.where && modelFilter.where.tenantId) {
* filter.where.tenantId = modelFilter.where.tenantId;
* }
* return filter;
* };
* };
* ```
*
* @param {Number} since Return only changes since this checkpoint.
* @param {Object} modelFilter Filter describing which model instances to
* include in the list of changes.
* @returns {Object} The filter object to pass to `Change.find()`. Default:
* ```
* {where: {checkpoint: {gte: since}, modelName: this.modelName}}
* ```
*/
PersistedModel.createChangeFilter = function(since, modelFilter) {
return {
where: {
checkpoint: {gte: since},
modelName: this.modelName,
},
};
};
/**
* Add custom data to the Change instance.
*
* Models should override this function to duplicate model instance properties
* to the Change instance properties, typically to allow the changes() method
* to filter the changes using these duplicated properties directly while
* querying the Change model.
*
* ```js
* module.exports = (TargetModel, config) => {
* TargetModel.prototype.fillCustomChangeProperties = function(change, cb) {
* var inst = this;
* const base = this.constructor.base;
* base.prototype.fillCustomChangeProperties.call(this, change, err => {
* if (err) return cb(err);
*
* if (inst && inst.tenantId) {
* change.tenantId = inst.tenantId;
* } else {
* change.tenantId = null;
* }
*
* cb();
* });
* };
* };
* ```
*
* @callback {Function} callback
* @param {Error} err Error object; see [Error object](http://loopback.io/doc/en/lb3/Error-object.html).
*/
PersistedModel.prototype.fillCustomChangeProperties = function(change, cb) {
// no-op by default
cb();
};
PersistedModel.setup();
return PersistedModel;
};