In what situation does changed event trigger in loopback? - loopbackjs

/common/models/meetups.js
module.exports = function(Meetups) {
Meetups.on('changed', function(inst) {
console.log('--------------------------------------');
console.log('model with id %s has been changed', inst.id);
console.log(inst);
console.log('--------------------------------------');
});
}
I have a model Meetups and i want to listen for CUD(Create, Update and Delete) operations in the model and i listen for 'changed' event but adding, deleting document from the model didn't trigger the event?

Loopback 3 does not support changed event any more. You can read more about similar question here:
How to make Loopback models events work?
What you do have, are hooks:
https://loopback.io/doc/en/lb3/Operation-hooks.html
https://loopback.io/doc/en/lb3/Remote-hooks.html
You should find your answer there

This might be work for you
module.exports = function(Model) {
Model.observe('before save', function(ctx, next) {
console.log("here before save");
})
}
module.exports = function(Model) {
Model.observe('after save', function(ctx, next) {
console.log("here after save");
})
}

Related

How to continue even if Ember.js model hook doesn't load all promises?

I'm loading a route. Its model hook loads some models. Some are fetch from ember store and some are promises requested through AJAX:
model: function () {
return Em.RSVP.hash({
//the server data might not be loaded if user is offline (application runs using appcache, but it's nice to have)
someServerData: App.DataService.get(),
users: this.store.find('user')
});
}
The App.DataService.get() is defined as:
get: function () {
return new Ember.RSVP.Promise(function(resolve, reject) {
//ajax request here
});
}
Obviously if the request is rejected, the flow is interrupted and I cannot display the page at all.
Is there a way to overcome this?
Ember.RSVP.hashSettled is exactly meant for this purpose.
From tildeio/rsvp.js Github repository:
hashSettled() work exactly like hash(), except that it fulfill with a hash of the constituent promises' result states. Each state object will either indicate fulfillment or rejection, and provide the corresponding value or reason. The states will take one of the following formats:
{ state: 'fulfilled', value: value }
or
{ state: 'rejected', reason: reason }
Here is an example for using it (working JS Bin example):
App.IndexRoute = Ember.Route.extend({
fallbackValues: {
firstProperty: null,
secondProperty: null
},
model: function() {
var fallbackValues = this.get('fallbackValues');
return new Ember.RSVP.Promise(function(resolve, reject) {
Ember.RSVP.hashSettled({
firstProperty: Ember.RSVP.Promise.resolve('Resolved data despite error'),
secondProperty: (function() {
var doomedToBeRejected = $.Deferred();
doomedToBeRejected.reject({
error: 'some error message'
});
return doomedToBeRejected.promise();
})()
}).then(function(result) {
var objectToResolve = {};
Ember.keys(result).forEach(function(key) {
objectToResolve[key] = result[key].state === 'fulfilled' ? result[key].value : fallbackValues[key];
});
resolve(objectToResolve);
}).catch(function(error) {
reject(error);
});
});
}
});
fallbackValues can be useful for managing resolved hash's properties' fallback values without using conditions inside the promise function.
Taking into account that Ember.RSVP.hashSettled is not available in my Ember version. I come up with the following solution:
model: function(params) {
var self = this;
return new Em.RSVP.Promise(function(resolve, reject){
// get data from server
App.DataService.get().then(function(serverData) { //if server responds set it to the promise
resolve({
serverData: serverData,
users: self.store.find('user')
});
}, function(reason){ //if not ignore it, and send the rest of the data
resolve({
users: self.store.find('user')
});
});
});
}

Ember-simple-auth ApplicationRoute model function

I have classic setup of Ember-simple-auth, in ApplicationRoute I use
model: function () {
return Ember.RSVP.hash({
user: this.store.find('gsUser').then(function(data) {
return data.get('content')[0]
})
});
},
setupController: function(controller, model) {
this.controllerFor('user').set('content', model.user);
}
When user losts authorization, and you open the page. ApplicationRoute::model is fired first, server returns 401 and other execution is stopped.
GET http://localhost:8000/app_dev.php/api/1/users.json 401 (Unauthorized)
Error while loading route: undefined
model should be fired only when authentication is successfull.
I saw that there is sessionAuthenticationSucceeded but I've tried all the ways to listen to it, noone worked. How to listen to this event and get data from server when user is successfully authenticated?
11/06 22:57 UPDATE:enter code here
One solution for this problem that I've managed to achieve, but it seems totally not ember way:
App.ApplicationRoute = Ember.Route.extend(Ember.SimpleAuth.ApplicationRouteMixin, {
skipModelLoading: false,
beforeModel: function() {
this.set('skipModelLoading', !this.get('session').get('isAuthenticated'));
},
model: function () {
if (this.get('skipModelLoading')) {
return;
}
return Ember.RSVP.hash({
user: this.store.find('gsUser').then(function(data) {
return data.get('content')[0]
})
});
},
setupController: function(controller, model) {
if (this.get('skipModelLoading')) {
return;
}
this.controllerFor('user').set('content', model.user);
}
});
I assume you're loading the authenticated user in that model method. I'd do it differently and attach that property to the session as shown in this example: https://github.com/simplabs/ember-simple-auth/blob/master/examples/4-authenticated-account.html#L101
I think I found a more ember-way solution for my problem:
App.ApplicationRoute = Ember.Route.extend(Ember.SimpleAuth.ApplicationRouteMixin, {
onSessionIsAuthenticated: function () {
var isAuthenticated = this.get('session').get('isAuthenticated');
if (!isAuthenticated) {
return false;
}
var userController = this.controllerFor('user');
return Ember.RSVP.hash({
user: this.store.find('gsUser').then(function (data) {
userController.set('content', data.get('content')[0]);
})
});
}.observes('session.isAuthenticated').on('init')
});

Using tryInvoke when controller actions are wrapped

Newest guidelines state to wrap controller actions inside a
actions: {
loadMore: function() {}
}
When I do so the code I previously had to fire an action on a controller no longer works:
Ember.tryInvoke(view.get('controller'), 'loadMore');
What would be the proper way to get this going again?
Edit
The complete code that uses the tryInvoke:
didInsertElement: function() {
'use strict';
var view = this;
this.$().bind('inview', function(event, isInView, visiblePartX, visiblePartY) {
if (isInView) {
Ember.tryInvoke(view.get('controller'), 'loadMore');
}
});
},
You can use the Ember.ViewTargetActionSupport, and set the action property to the action name that you want, in that case loadMore. Using triggerAction will send the action.
Because the jquery event is detached from ember run loop I wrapped the triggerAction in Ember.run.
App.YourView = Ember.View.extend(Ember.ViewTargetActionSupport, {
action: 'loadMore',
didInsertElement: function() {
'use strict';
var view = this;
this.$().bind('inview', function(event, isInView, visiblePartX, visiblePartY) {
if (isInView) {
Ember.run(function() {
view.triggerAction();
});
}
});
},
});
Are you sure you're getting the controller right? According to a commit a couple months ago in Ember 1.2, the controller is now accessible from a view as "targetObject" rather than "controller":
https://github.com/emberjs/ember.js/commit/326af5a9c88df76f5effe11156a07b64c8b178a3#packages/ember-handlebars/lib/controls/text_support.js

Incrementally adding models to controller

I have a standard issue route like:
App.MessagesRoute = Ember.Route.extend({
model: function() {
return App.Message.find();
}
});
Which works great for the existing set of messages that i get from a REST endpoint. But I also get new messages via a websocket. How in the RC2 routing architecture (and non-Ember Data store) how do I plumb new message like these into Ember cleanly?
I solved this using the Ember.Instrumentation framework element that's talked about in How to fire an event to Ember from another framework.
Here's my complete code:
...
// this is fired from my websocket message reception code.
Ember.Instrumentation.instrument('onMessage', message);
...
App.MessagesRoute = Ember.Route.extend({
setupController: function(controller, model) {
Ember.Instrumentation.subscribe('onMessage', {
before: function(name, timestamp, message) {
controller.send('onMessage', message);
},
after: function() {}
});
},
model: function() {
return App.Message.find();
}
});
App.MessagesController = Ember.ArrayController.extend({
onMessage: function(message) {
this.unshiftObject(message);
}
});

Delete associated model with ember-data

I have two models:
App.User = DS.Model.create({
comments: DS.hasMany('App.Comment')
});
App.Comment = DS.Model.create({
user: DS.belongsTo('App.User')
});
When a user is deleted, it also will delete all its comments on the backend, so I should delete them from the client-side identity map.
I'm listing all the comments on the system from another place, so after deleting a user it would just crash.
Is there any way to specify this kind of dependency on the association? Thanks!
I use a mixin when I want to implement this behaviour. My models are defined as follows:
App.Post = DS.Model.extend(App.DeletesDependentRelationships, {
dependentRelationships: ['comments'],
comments: DS.hasMany('App.Comment'),
author: DS.belongsTo('App.User')
});
App.User = DS.Model.extend();
App.Comment = DS.Model.extend({
post: DS.belongsTo('App.Post')
});
The mixin itself:
App.DeletesDependentRelationships = Ember.Mixin.create({
// an array of relationship names to delete
dependentRelationships: null,
// set to 'delete' or 'unload' depending on whether or not you want
// to actually send the deletions to the server
deleteMethod: 'unload',
deleteRecord: function() {
var transaction = this.get('store').transaction();
transaction.add(this);
this.deleteDependentRelationships(transaction);
this._super();
},
deleteDependentRelationships: function(transaction) {
var self = this;
var klass = Ember.get(this.constructor.toString());
var fields = Ember.get(klass, 'fields');
this.get('dependentRelationships').forEach(function(name) {
var relationshipType = fields.get(name);
switch(relationshipType) {
case 'belongsTo': return self.deleteBelongsToRelationship(name, transaction);
case 'hasMany': return self.deleteHasManyRelationship(name, transaction);
}
});
},
deleteBelongsToRelationship: function(name, transaction) {
var record = this.get(name);
if (record) this.deleteOrUnloadRecord(record, transaction);
},
deleteHasManyRelationship: function(key, transaction) {
var self = this;
// deleting from a RecordArray doesn't play well with forEach,
// so convert to a normal array first
this.get(key).toArray().forEach(function(record) {
self.deleteOrUnloadRecord(record, transaction);
});
},
deleteOrUnloadRecord: function(record, transaction) {
var deleteMethod = this.get('deleteMethod');
if (deleteMethod === 'delete') {
transaction.add(record);
record.deleteRecord();
}
else if (deleteMethod === 'unload') {
var store = this.get('store');
store.unloadRecord(record);
}
}
});
Note that you can specify via deleteMethod whether or not you want to send the DELETE requests to your API. If your back-end is configured to delete dependent records automatically, then you will want to use the default.
Here's a jsfiddle that shows it in action.
A quick-and-dirty way would be to add the following to your user model
destroyRecord: ->
#get('comments').invoke('unloadRecord')
#_super()
I adapted the answer of #ahmacleod to work with ember-cli 2.13.1 and ember-data 2.13.0. I had an issue with nested relationships and the fact that after deleting an entity from the database its id was reused. This lead to conflicts with remnants in the ember-data model.
import Ember from 'ember';
export default Ember.Mixin.create({
dependentRelationships: null,
destroyRecord: function() {
this.deleteDependentRelationships();
return this._super()
.then(function (model) {
model.unloadRecord();
return model;
});
},
unloadRecord: function() {
this.deleteDependentRelationships();
this._super();
},
deleteDependentRelationships: function() {
var self = this;
var fields = Ember.get(this.constructor, 'fields');
this.get('dependentRelationships').forEach(function(name) {
self.deleteRelationship(name);
});
},
deleteRelationship (name) {
var self = this;
self.get(name).then(function (records) {
if (!records) {
return;
}
var reset = [];
if (!Ember.isArray(records)) {
records = [records];
reset = null;
}
records.forEach(function(record) {
if (record) {
record.unloadRecord();
}
});
self.set(name, reset);
});
},
});
Eventually, I had to set the relationship to [] (hasMany) or null (belongsTo). Else I would have run into the following error message:
Assertion Failed: You cannot update the id index of an InternalModel once set. Attempted to update <id>.
Maybe this is helpful for somebody else.