I just need to use the res.render function at some places but it is not passed to the callback I am using. Isn't there somewhere a global version of the render function or is there another way to access this?
In Sails v0.10.4 there is
sails.renderView(viewPath, options, callback);
Also, when rendering emails, you probably don't need to use a layout. So before calling sails.renderView, add
options.layout = false;
You don't need it at all places, really.
res is a response object and it makes sense only in controllers, because only controllers deal with request handling and response rendering.
Do you want to use res.render from models, services? Maybe it's because you think that all your code is always in we_have_request_and_user_is_waiting_for_response state.
Well, It's not true: model methods and services can be called from sails console, or from background workers, or from code, than runs by schedule. In these cases we don't have res object at all.
Controllers are place specially designed to contain user actions responding logic. So, you should place that logic in controllers. MVC
Technically, previous speaker is somewhat right: there is a reason res exists only within controllers. For example, what if it's a CLI application, and there's simply no request/ response in HTTP-meaning?
That said, if you just need to render some HTML for one or another purpose, you can always use global Express' renderer, which doesn't require response to be presented: it's accessible via sails.express.app.render, see Express' documentation for the method's params.
Related
I am building an app in angular, which consumes different APIs and Gives options for the user to select it will be recorded and sent back to the server.
I have designed it as follows.
All the common logic in Main Controller and all other options in different controllers as the child of main controller.
Main Controller retrieve all the data that are required to run the app.
which is consumed by all other child controllers.
To make sure data is loaded I am using promise attached to scope. So all the child controller will know data loaded.
I have moved data updation part of all child controllers to main controller
because all the updates happen in one object.
Child Controller emit/broadcast to communicate between child and main. So when update happens child will emit an event with data which will be captured by Main and it will do the update.
MainController {
$scope.loaded = DataService.get();
$scope.userOptions = {};
$scope.$on('update',function(){
updateUserOptions();
})
}
ChildController {
$scope.loaded.then(function(){
//all logic of child controller
}
$scope.onselect = function(){
$scope.$emit('update',data);
}
}
Questions
Is it a good practice to use events between controllers ?
is it good to use promise attached to scope for child controllers ?
Will it improve my code if I start using services ?
I will try to answer your question based on my own experience. Recently I've built a single page application and I've refactored its architecture.
Here are my answers:
Is it a good practice to use events between controllers? IMHO, it is the most flexible way to share information between all controllers even if they have isolated scope (using $broadcast or $emit for example). This is called the Observer design pattern. However, you can use services instead of events to share data between them. If you are going to use $rootScope, be careful as all the $scopes inherit from $rootScope.
is it good to use promise attached to scope for child controllers ? Firstly, you have to learn about how scope inheritance works. You have to take care to avoid property shadow in JS. Secondly, I would move out all the logic from scope.loaded in ChildController to a service such as ChildService. Keeping the business logic (such as request, etc) in Services instead of Controllers, will ensure it can be re-used.
Segregation of business logic is good design principle.
Will it improve my code if I start using services ? I answered this question above.
In addition, in order to build a good architecture I've read this angular style guide written by John Papa.
I recommend the following changes:
To make sure data is loaded I am using promise attached to scope. So all the child controller will know data loaded.. Instead I would emit a custom 'loaded' event in the MainController using $scope.$emit('loaded'). After that, in the ChildController I would use $scope.$on('loaded', function(){}) to handle the event.
I would move the updateUserOptions function to a service and inject the it into just the controllers that need it.
I hope that helps!
Is it a good practice to use events between controllers ? Not as the main form of data sharing, but you can use it to notify about system events, such as data ready.
Is it good to use promise attached to scope for child controllers ? Don't use scope inheritance, it causes lots of annoying problems.
Will it improve my code if I start using services ? Yep.
This is what I would do in your place:
dataService - this service is responsible for all data coming in / going out. Whenever a request for data is made (no matter which controller asked for the data), the service caches the data (save the promise is good enough). All further requests get the cached data unless they specify they want a fresh data. Whenever data is updated (1st time or refresh), the service broadcasts a 'dataReady' event via $rootScope to which the main controller and other subscribers can listen.
The service is also responsible for data updates, and when the data is updated you can also broadcast an event via the $rootScope.
When the event is activated, all subscribers query the service, and get the data they need.
Controllers - avoid controllers, use directives with isolated scope, and pass the data between them using attributes. In this way you can be sure that each directive gets what it needs, and not everything. The directives can communicate using attributes, services, broadcast / emit or require their parents / siblings if they work closely together.
Is it a good practice to use events between controllers ?
No it's not, it will be deprecated by Angular JS 2.0. It also often leads to unmanagable tangle of events which are hard to understand and debug. Use services to share data between controllers. (Inject same service into multiple controllers, service then holds data, controllers bind to that data and are automatically synchronized) I wrote a blog post explaining this use case.
Is it good to use promise attached to scope for child controllers ?
No it's not. Use promises and resolve data in services. Don't use $scope at all but use controllerAs syntax instead. $scope was deprecated also in Angular JS 1.X because it's usage leads to many different problems with scope inheritance.
Will it improve my code if I start using services ?
YES! Use services for all logic and data manipulation. Use controllers only for UI interaction and delegate everything to services. Also use ui-router for managing state of your application.
I'm not going to answer your questions directly as I have some other comments as well. I think the approach you mentioned is not the best way to build angular applications.
All the common logic in Main Controller and all other options in different controllers as the child of main controller.
It's against all angular style guides to place common logic in controllers. Controllers should only be used for the logic related to the view (data binding, validation, ...). Because the code inside a controller is not reusable, the less code you have in a controller the better. The more logic you have in services, the more scalable your application becomes.
Fix: I suggest you create a service that retrieves data from the server, and inject this service in controllers as you need. Notice also this way offers better dependency management as you can keep track of which controllers need which services exactly.
Nested controllers should be avoided when possible, because angular keeps track of all the active scopes and re-evaluates them in every $apply() loop.
Fix: same as #1, use services instead of the main controller.
To make sure data is loaded I am using promise attached to scope. So all the child controller will know data loaded.
Using a promise for data retrieval is a good practice. But, again, keeping it in a service is much cleaner than main controller.
I have moved data updation part of all child controllers to main controller because all the updates happen in one object.
Child Controller emit/broadcast to communicate between child and main. So when update happens child will emit an event with data which will be captured by Main and it will do the update.
Fix: use a service with an update function instead of events. Events are harder to debug and track. And you need to unregister event handlers on destroying a controller. If you can use a function/promise instead of events, then it's usually a better idea.
Is it a good practice to use events between controllers ?
A problem with your current set-up is that you're implicitly relying on the hierarchy of your controllers (the fact that one is the child of the other) - because you emit the event, only scopes higher up on the hierarchy can catch it. Besides being an implicit connection (that a developer has to remember), this also limits he extendability of this feature.
On the other hand, if you injected a shared service into all the controllers that need it, the connection between the controllers would become explicit and documented, and their scopes' position in the hierarchy independent. This will make your architecture easier to maintain, with the added benefit of also being easier to test, for one.
You can still implement an observer pattern with a service.
is it good to use promise attached to scope for child controllers ?
The issue of polluting scopes pointed out in other answers is valid. This is one of the reasons why it's better to limit the number of objects you attach to your scope, and to use objects as bundles of variables on your scope instead of attaching all the variables to the scope directly.
(For an explanation of these reasons, see discussions about "always having a . in your bindings".)
(Of course, don't do this blindly just to reduce the number of variables, try to find semantic connections between variables that might be bundled together sensefully.)
Will it improve my code if I start using services ?
I think the above answers already outline the answer for this: yes. There are other benefits too, but this format is not best for too long answers, so I won't list anything else now.
All in all, these above pointers are not big issues with your code currently, but if you're looking for the best architecture, I think you can do better.
Answers:
No, it will be deprecated soon.
$scope is deprecated already.
Services is a great choice. Services allow us to share data and behaviour across other objects like controllers.
I have an app with two controllers where I want a change in one controller to affect (different) data stored in the other. tl;dr when I remove a category from the first controller, I want to edit any items in the second controller with that category, so that they will now be category-less.
As far as I can tell what I want is to use a service, but I feel it would be simpler if there were a way for me to simply edit the data inside the controller scope. So my questions are:
Is there a way to simply edit controller data or call controller methods from a service?
Otherwise, is it reasonable to store the latter controller's data in the service, even though the former controller only needs access to change it? How do I reference this data for the purpose of doing ng-repeats?
Edit: to clarify the data is a set of json objects which contain data for each category and each item, and the web page contains ng-repeats to go through and list each of them. I have a number of functions which edit both lists of data, and I want changes to one list to make changes in the other.
Your idea was correct, you should put all your business logic, including data that needs to be consistent between different parts of your application, into services. controllers should only manage the view and connect the data to it.
Keep in mind that services are Singletons - there is always only one instance of each service, holding your data.
To answer your question: I would argue that storing data in a service instead of a controller is always reasonable when it works (aka when the data is not specific to one of multiple views, but consistent throughout the current application state), and giving access to that data to manipulate it is perfectly fine - even better would be to put the manipulation logic into the service itself (or another service only for that) and to just let the controller connect to a call invoking that.
There is an article by Todd Motto on that topic (thin controllers)
I think it will be better use events for this purpose. In your first controller you can published the event on category deletion like below.
$scope.deleteCategory = function (category) {
$rootScope.$broadcast("categoryDeleted", category);
}
Then you can observe this event in any controller like below in second controller you can listen categoryDeleted event.
$scope.$on("categoryDeleted", function (event, category) {
// do whatever you want
});
Do not call controller directly from the service, this is a bad practice, not only in AngularJS, but in most languages frameworks.
The problem you have described ("a change in one controller to affect (different) data stored in the other") is a problem of communication between components. You can solve this issue with events, thus there is no need to move data from the second controller to the service.
Let's consider some example:
http://jsfiddle.net/simpulton/XqDxG/
When you click on the LOG button the this.broadcastItem() is invoked, and the 'handleBroadcast' event is broadcasted.
Other constrollers, controllerOne and controllerTwo, handle this event:
$scope.$on('handleBroadcast'
and do the things they want to do.
So, in yor case, you can introduce the 'categoryRemoved' event, and broadcast this event in the first controller. Once the event is broadcasted, your second controller handle it and edit its items.
Also you should pass the removed category in the event (instead of 'msg' in the example), so that second controller has to aware which exactly category has been removed.
In way you want to do that, $rootScope can be used (shared across controllers - modyfing in one, accessing in another), but its generally bad idea. Im not sure if I get it right but its typical situation when you actually need service with controlling some external data.. Its some static json you want to modify? Can you specify it more clearly ? :)
I have a repeated set of API calls in an Angular controller.
The relevant data is of course the API URI, POST or GET, some header data, and JSON objects. The API call always returns a JSON object.
I started to use a Directive but that seems most relevant for data that is used with $scope (e. g. in the View). This data runs under the radar and might eventually generate data used in the view but most usually not and most usually not in a way that can be abstracted.
So: Does this mean I shouldn't use a directive? If I don't use a directive, would it be better to use a JS Object (seems more modular) or Function (seems more variable friendly) to handle this code?
Yes, I get that objects can contain functions, but functions can also contain callbacks so...looking for kind of a "best practices" here. In terms of modularity and flexibility.
You should create Angular service for that.
https://docs.angularjs.org/guide/services
Your service will contain a method, lets say "getResults" which will make an API call and return either data or a promise ($http). Then you can inject you service to your controller and use that method to get the data and assign it to $scope.
An Angular service is certainly preferred to a more general JavaScript one because it allows you to take greater advantage of Angular's scope and other such things. Between Angular's Factory, Service, and Providers, a Service is the most in line with what you're trying to do since a Factory is too basic and generally used to solve smaller problems while a Provider is used -- as it says in the Angular docs -- "only when you want to expose an API for application-wide configuration that must be made before the application starts." Which is not what you're trying to do.
I have an app I am designing using node/mongo/angular, what I am not getting is how is the best way to get my data from mongo into my pages? I can use node, and thru my routes send back data from mongo with my template(hogan in this case), and bind using mustachejs. That works fine for most things. I have one screen that has a decent amount of drop down lists, to bind them for an edit scenario now seems a challenge. I would like to get them bound to an angular model and go about it that way. Is it better to get the data thru the route in node, then use something like ng-init and get it into angular? Or would I be better off not getting the data thru the route in node, and then using angular to perform a "get" request and bind that way?
From the documentation of ng-init, more precisely from the red warning alert at the top of the page...:
The only appropriate use of ngInit is for aliasing special properties of ngRepeat, as seen in the demo below. Besides this case, you should use controllers rather than ngInit to initialize values on a scope.
So no, do not use ng-init. While that can be a good strategy for lazy migrations from regular applications to single page applications, it's a bad idea from an architectural point of view.
Most importantly, you lose two things:
An API. The benefit of SPAs is that you have an API and that you're constantly developing and maintaining it, even before it has external users
A clean separation of concerns. Views are strictly limited to presentation, can be cached by the client and all data is transferred through JSON API endpoints.
I would say that the best way to get data from Mongo into your page, is as mnemosyn said, using an API.
Basicly, you can have your API route, f.ex '/api/data' configured and then it can be used by a angular service, (which can use ngResource to make things easier). Any controller that wishes to access this data can use the angular service to get it, do some stuff with it, and then update it using the same angular service.
I'm building an AngularJS app, and I would it to be respectful or the best practices.
Thus, when I have to call an external $resource or $http request, I do it in an external Service/Factory.
My problem is I don't know what is the best way for retrieving returned value of the Service into the calling Controller.
Currently, what I do is the following :
The controller calls the Service
The Service does the $http call and check the promise.
If promise is successful, the Service $broadcast an event with the returned object.
The Controller catches that event and does operations.
It works great and allows me to use the same event after different requests (ex: In a discussion, after retrieving all messages and after posted myself a message, the same event "new messages to display" is called)
.
But I finally decided to set up testing processes in my application (better late than never), and I realize that I could do it wrong.
--> When unit-testing my Controllers I want to mock some of my Services for returning given values. But as my Controller calls Services which doesn't returns anything (they fire events instead) I think it will be pretty hard and not natural to check Services "return" values. (I can always check if the Service has been called, but not the result).
.
Your opinion, have I done misconception errors ? I consider getting the promises directly into Controllers when calling Services, is this a good (better?) way to do it ?
I aware that each application have its own logic, but I think in AngularJS the number of "working" logics (that preserves modularity, and testability) are particularly restricted to some set of choices and best practices.
Any suggestion would be appreciated.
Without seeing your code, I have my ideas:
Your controller could receive that promise and do what it needs to do. There is no real need to broadcast anything. Your service call $http and then return the promise. When $http promise is resolved, your controller will know and can do what you need to do.
Testing functions in a service that doesn't return anything is not a problem, that is what spyOn is. You can check that the function has been called and that should be enough for your controller. You don't actually care what happens in the service, you cares about your controller (in the test controller, of course).
Please don't use events for such kind of interaction. They make a mess inside of the code and reduce maintainability. Sometimes you can use them but it is fine only for certain operations and for some specific situations. Using promises is good approach.
Here you have three different options:
Just return the $http promise object and handle it inside of your controller
Make your own promise with $q service and place inside of it your own logic for handling the response from $http or direct returning result (it is more flexible approach than the first one)
Just pass to the services a function callback which you can call there inside of your service to pass the result back to controller.
But you definitely don't need to use events in these cases.
What is related to unit-testing you will configure $httpBackend service to mock your queries and in this case everything will work fine and you can test anything you need ($httpBackend). It means that you can inject your service and it works fine (as instead of real http call it will return the object configured as a response in the $httpBackend). So you can still test your controller without need to make anything complicated to your services.