loopback/lib/models/model.js

399 lines
9.4 KiB
JavaScript

/*!
* Module Dependencies.
*/
var loopback = require('../loopback');
var compat = require('../compat');
var ModelBuilder = require('loopback-datasource-juggler').ModelBuilder;
var modeler = new ModelBuilder();
var assert = require('assert');
/**
* The built in loopback.Model.
*
* @class
* @param {Object} data
*/
var Model = module.exports = modeler.define('Model');
Model.shared = true;
/*!
* Called when a model is extended.
*/
Model.setup = function () {
var ModelCtor = this;
ModelCtor.sharedCtor = function (data, id, fn) {
if(typeof data === 'function') {
fn = data;
data = null;
id = null;
} else if (typeof id === 'function') {
fn = id;
if(typeof data !== 'object') {
id = data;
data = null;
} else {
id = null;
}
}
if(id && data) {
var model = new ModelCtor(data);
model.id = id;
fn(null, model);
} else if(data) {
fn(null, new ModelCtor(data));
} else if(id) {
ModelCtor.findById(id, function (err, model) {
if(err) {
fn(err);
} else if(model) {
fn(null, model);
} else {
err = new Error('could not find a model with id ' + id);
err.statusCode = 404;
fn(err);
}
});
} else {
fn(new Error('must specify an id or data'));
}
}
// before remote hook
ModelCtor.beforeRemote = function (name, fn) {
var self = this;
if(this.app) {
var remotes = this.app.remotes();
var className = compat.getClassNameForRemoting(self);
remotes.before(className + '.' + name, function (ctx, next) {
fn(ctx, ctx.result, next);
});
} else {
var args = arguments;
this.once('attached', function () {
self.beforeRemote.apply(self, args);
});
}
};
// after remote hook
ModelCtor.afterRemote = function (name, fn) {
var self = this;
if(this.app) {
var remotes = this.app.remotes();
var className = compat.getClassNameForRemoting(self);
remotes.after(className + '.' + name, function (ctx, next) {
fn(ctx, ctx.result, next);
});
} else {
var args = arguments;
this.once('attached', function () {
self.afterRemote.apply(self, args);
});
}
};
// Map the prototype method to /:id with data in the body
ModelCtor.sharedCtor.accepts = [
{arg: 'id', type: 'any', http: {source: 'path'}}
// {arg: 'instance', type: 'object', http: {source: 'body'}}
];
ModelCtor.sharedCtor.http = [
{path: '/:id'}
];
ModelCtor.sharedCtor.returns = {root: true};
return ModelCtor;
};
/*!
* Get the reference to ACL in a lazy fashion to avoid race condition in require
*/
var ACL = null;
function getACL() {
return ACL || (ACL = require('./acl').ACL);
}
/**
* Check if the given access token can invoke the method
*
* @param {AccessToken} token The access token
* @param {*} modelId The model id
* @param {String} method The method name
* @param callback The callback function
*
* @callback {Function} callback
* @param {String|Error} err The error object
* @param {Boolean} allowed is the request allowed
*/
Model.checkAccess = function(token, modelId, method, callback) {
var ANONYMOUS = require('./access-token').ANONYMOUS;
token = token || ANONYMOUS;
var ACL = getACL();
var methodName = 'string' === typeof method? method: method && method.name;
ACL.checkAccessForToken(token, this.modelName, modelId, methodName, callback);
};
/*!
* Determine the access type for the given `RemoteMethod`.
*
* @api private
* @param {RemoteMethod} method
*/
Model._getAccessTypeForMethod = function(method) {
if(typeof method === 'string') {
method = {name: method};
}
assert(
typeof method === 'object',
'method is a required argument and must be a RemoteMethod object'
);
var ACL = getACL();
switch(method.name) {
case'create':
return ACL.WRITE;
case 'updateOrCreate':
return ACL.WRITE;
case 'upsert':
return ACL.WRITE;
case 'exists':
return ACL.READ;
case 'findById':
return ACL.READ;
case 'find':
return ACL.READ;
case 'findOne':
return ACL.READ;
case 'destroyById':
return ACL.WRITE;
case 'deleteById':
return ACL.WRITE;
case 'removeById':
return ACL.WRITE;
case 'count':
return ACL.READ;
break;
default:
return ACL.EXECUTE;
break;
}
}
// setup the initial model
Model.setup();
/**
* Get a set of deltas and conflicts since the given checkpoint.
*
* See `Change.diff()` for details.
*
* @param {Number} since Find changes since this checkpoint
* @param {Array} remoteChanges An array of change objects
* @param {Function} callback
*/
Model.diff = function(since, remoteChanges, callback) {
var Change = this.getChangeModel();
Change.diff(this.modelName, since, remoteChanges, callback);
}
/**
* Get the changes to a model since a given checkpoing. Provide a filter object
* to reduce the number of results returned.
* @param {Number} since Only return changes since this checkpoint
* @param {Object} filter Only include changes that match this filter
* (same as `Model.find(filter, ...)`)
* @callback {Function} callback
* @param {Error} err
* @param {Array} changes An array of `Change` objects
* @end
*/
Model.changes = function(since, filter, callback) {
var idName = this.idName();
var Change = this.getChangeModel();
var model = this;
filter = filter || {};
filter.fields = {};
filter.where = filter.where || {};
filter.fields[idName] = true;
// this whole thing could be optimized a bit more
Change.find({
checkpoint: {gt: since},
modelName: this.modelName
}, function(err, changes) {
if(err) return cb(err);
var ids = changes.map(function(change) {
return change.modelId;
});
filter.where[idName] = {inq: ids};
model.find(filter, function(err, models) {
if(err) return cb(err);
var modelIds = models.map(function(m) {
return m[idName];
});
callback(null, changes.filter(function(ch) {
return modelIds.indexOf(ch.modelId) > -1;
}));
});
});
}
/**
* Create a checkpoint.
*
* @param {Function} callback
*/
Model.checkpoint = function(cb) {
var Checkpoint = this.getChangeModel().Checkpoint;
this.getSourceId(function(err, sourceId) {
if(err) return cb(err);
Checkpoint.create({
sourceId: sourceId
}, 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
* @options {Object} options
* @property {Object} filter Replicate models that match this filter
* @callback {Function} callback
* @param {Error} err
* @param {Array} conflicts A list of changes that could not be replicated
* due to conflicts.
*/
Model.replicate = function(since, targetModel, options, callback) {
var sourceModel = this;
var diff;
var updates;
var tasks = [
getLocalChanges,
getDiffFromTarget,
createSourceUpdates,
bulkUpdate,
sourceModel.checkpoint.bind(sourceModel)
];
async.waterfall(tasks, function(err) {
if(err) return callback(err);
callback(null, diff.conflicts);
});
function getLocalChanges(cb) {
sourceModel.changes(since, options.filter, cb);
}
function getDiffFromTarget(sourceChanges, cb) {
targetModel.diff(since, sourceChanges, cb);
}
function createSourceUpdates(_diff, cb) {
diff = _diff;
sourceModel.createUpdates(diff.deltas, cb);
}
function bulkUpdate(updates, cb) {
targetModel.bulkUpdate(updates, cb);
}
}
/**
* Create an update list (for `Model.bulkUpdate()`) from a delta list
* (result of `Change.diff()`).
*
* @param {Array} deltas
* @param {Function} callback
*/
Model.createUpdates = function(deltas, cb) {
var Change = this.getChangeModel();
var updates = [];
var Model = this;
var tasks = [];
var type = change.type();
deltas.forEach(function(change) {
change = new Change(change);
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);
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 Model.createUpdates())
* @param {Function} callback
*/
Model.bulkUpdate = function(updates, callback) {
var tasks = [];
var Model = this;
var idName = Model.idName();
var Change = this.getChangeModel();
updates.forEach(function(update) {
switch(update.type) {
case Change.UPDATE:
case Change.CREATE:
tasks.push(Model.upsert.bind(Model, update.data));
break;
case: Change.DELETE:
var data = {};
data[idName] = update.change.modelId;
var model = new Model(data);
tasks.push(model.destroy.bind(model));
break;
}
});
async.parallel(tasks, callback);
}
Model.getChangeModel = function() {
}