Services.pdf - Microsoft Word Web App. Using Angular.js Factories to Get Remote Data | developer.foo("David's blog"); In this post, I’d like to show the differences between using an Angular.js factory to get local JSON data vs remote data via an AJAX call. For this example, I’m assuming that we have a JSON dataset that describes different types of fruit, for example: At it’s simplest, an Angular.js view to iterate over this data could look like the following HTML: A Hardcoded Angular.js Controller and Factory In the HTML view, we can see that an Angular.js controller called fruitsController is being used within a module called fruitsApp.
If we wanted to get data locally rather than via HTTP, we could declare a controller and factory as follows: This is a very simple controller and factory. A Dynamic Angular.js Controller and Factory Using AJAX The above exampe will work for getting data, but isn’t of much use for dynamically generated content.
In this example, you can see that the controller makes a request to the factory which then calls an asynchronous function ($http.get) to get the data. Angular service or factory? Tl;dr is at the end In various AngularJS tutorials and documentation, the authors choose to use service or factory but don't explain why you would use one or the other. Few mention that value and constant are also options. Let's see why you would use one over the other. We should also understand how providers work: provider Here's the source for the provider method: function provider(name, provider_) { if (isFunction(provider_) || isArray(provider_)) { provider_ = providerInjector.instantiate(provider_); } if (!
Name is a string. provider_ can be one of three things: function If a function is passed in, the function is called with dependency injection and should return an object with a $get method. Whatever the second arg to provider is, you eventually end up with an object that has a $get method. // You can run this // Create a modulevar hippo = angular.module('hippo', []); // Get the injector (this happens behind the scenes in angular apps)var injector = angular.injector(['hippo', 'ng']); Using an AngularJS Factory to Interact with a RESTful Service - Dan Wahlin.
What’s covered in this Post? Creating a RESTful Service Creating an AngularJS Module Creating a Factory Creating a Controller AngularJS provides a great framework for building robust Single Page Applications (SPAs) and provides built-in support for routing, MV*-style programming, services and factories, modules, testing, and much more. Although Angular can consume virtually any HTTP resource, in this post I’m going to focus on using it to consume a RESTful API created using ASP.NET Web API (note that any back-end service could be used). If you’ve worked with jQuery before then you’re used to calls such as $.getJSON() or $.ajax().
Although Angular plays really well with jQuery, it has built-in HTTP functionality that can be used out of the box and a way to encapsulate data functionality using factories or services. Here’s a quick review of some of the key players in AngularJS. Creating a RESTful Service Creating an AngularJS Module Creating a Factory Creating the Controller Summary. Understanding service types. Angular comes with different types of services. Each one with its own use cases. Something important that you have to keep in mind is that the services are always singleton, it doesn’t matter which type you use. This is the desired behavior. NOTE: A singleton is a design pattern that restricts the instantiation of a class to just one object. Let’s start with my own opinion about services. Constant Example: A constant is a useful service often used to provide default configurations in directives. As a constant, the values we put in there can’t be changed in any way.
Try it Value A value service is like the constant service but the first one can be changed. Factory The Factory is the most common used service. A factory is a service which can return any datatype. As I said before, all types are singleton, so if we modify foo.variable in one place, the other places will have that change too. Service The service service works much the same as the factory one. Provider Bonus 1: Decorator Conclusion. Javier Lerones: Preloading data using deferred promises in Angular.js. I’ve been using Angular.js for a while now and I can say that I absolutely love it. The learning curve is specially steep if you are coming from jQuery-only front end development but once you get the hang of it, it is a fantastic MVW framework.
I am however, trying to find the best way to pre-load data into a controller by using deferred promises inside a factory. Let me first explain why. In the app that I am building I need to access an asynchronous source of data that reads from local storage in chrome. At first I thought it would be Ok to create a factory wrapping the methods that that storage adapter provides, but this got messy very fast and now my controllers are becoming clutter and hard to read. So now I need to tackle the problem by using a more standard approach: services and promises.
The new data layer will have two main components: 1. 2. Hard to understand without some code, so here it goes. Now this will be the data factory (service) that will access the above: Next steps. Angular service or factory? Custom Service - Counter. Factory vs Service. Factory - Pushing search form data to another controller. Edit this Fiddle. Promises and Deferred objects in jQuery and AngularJS. Series of articles about futures/promises without JavaScript would not be complete. Futures (more commonly named promises in JS land) are ubiquitous in JavaScript to the point where we almost don't recognize them any more. AJAX, timeouts and whole Node.JS are built on top of asynchronous callbacks. Nested callbacks (as we will see in just a second) are so hard to follow and maintain that the callback hell term was coined. In this article I will explain how promises can improve readability and modularize your code. Introducing promise object Let's take the first, simplest example using AJAX and $.getJSON() helper method: $.getJSON('square/3', function(square) { console.info(square); }); square/3 is an AJAX resource that yields 9 (3 square).
Suddenly business logic is buried deeply inside nested callbacks (as a matter of fact this is still not bad, but it tends to be much worse in practice). What does square() or more precisely $.getJSON() return? So, what's the difference? Or: in jQuery. Post: Angular JS, Lift 3, and Streaming Promises. Simple AngularJS Lift has always had the best server-push technology around. Why? It's secure, it deals well with spotty connections, it respects the limited number of HTTP connections between the client and the server, and so much more. Angular JS is a very exciting UI package that makes building dynamic single-page applications a snap because there's a 2-way binding between the model and the UI so that changes in the model are correctly reflected in the UI. And the whole binding is declarative so that once you use a model item in the UI, that part of the UI is always updated when the model changes.
Round Trips The default way to build Angular JS apps is to associate certain events in the client with REST calls to the server and when the REST calls are satisfied, the model is updated and UI is redrawn. But there are issues: Lift's round trips have the following advantages over simple REST: Simple Round Trip And to invoke the code from the client: But it Streams And our client looks like:
$http/promise. AngularJS. Models and Services in Angular. Image from What's a Model? What's a Service? I read over a post by Joel Hooks today called Modeling Data and State in Your AngularJS Application and the idea was put forward that you can clean up your Controllers by (basically) using Angular's service as a model. The idea is a good one: Clean Controllers are Godly Controllers but there's some confusion in the post that I think will end up spreading.
Straight up-front: All services (service(), factory(), provider()) in Angular are SINGLETONS. It's difficult under any circumstances to consider a Singleton as a model. There are so many jargon-filled terms disseminated throughout different approaches to software design... but I think we can agree that a model is representative of data (as opposed to a Domain Model which is all of your stuff under a big umbrella).
One might consider this list to be two instances of a single Model, Author: Domain vs. Pjax and AngularJS | While I Pondered... What is the difference between module.factory and module.service and how might both be applied? Lazy-loaded asynchronous resources. Service - applied to scope.