We are using a 3rd part i18n module for translations in my app. Specifically https://github.com/doshprompt/angular-localization
Problem
The issue we are having is that the locale service is needed before it can possibly be loaded. If it is needed in a state we can resolve locale on the state resolve but if a script has to run before any state is even requested there is a timing conflict.
In this example I'm trying to load a service that needs locale before locale is loaded or could possibly have enough time to load.
Example
angular.module('config', []).service('myService', ['ngLocalization', function(locale) {
return {
foo: locale.getString('bar')
}
}]);
angular.module('app', ['config']).run(['myService', function(myService) {
/// ... do stuff ...
}]);
I'm anti-mess
This may seem simple- just add locale.ready('common').then(function() {}); to the service. And that's something we COULD do.. EVERYWHERE (there are a lot of places). But we don't want to add this confusing mess to our code that is unstable. And we don't want to get into the habit of having every service, controller, directive, etc etc. checking that all the possible dependencies and their resources are loaded independently.
$httpBackend Solution?
$httpBackend is for unit testing but can it be used- or is there another service to use- to set the respond to an http request? And if there is already a response is it then synchronous? Then when the config module loads it makes a ready request for all needed lang files which get applied immediately and the timing conflicts will go away.
Thoughts?
Related
I had a use-case where I wanted to make the session timeout of the application configurable by making a call to REST api and get the value using $http. But as I found in this link how to inject dependency into module.config(configFn) in angular that services cannot be injected in config method, I have found this solution to make this work in the config:
var $http = angular.injector(['ng']).get('$http');
This is working fine, what is the difference between the two approaches and why this is working ? Also is there any limitation of using this approach.
angular.injector creates a new injector (application instance). It is misused most times and rarely ever needed in production.
It will have its own $http, $rootScope, $q, etc instances:
angular.injector(['ng']).get('$http') !== angular.injector(['ng']).get('$http');
The use of angular.injector in config block is an antipattern. It will result in untestable and potentially buggy code. $http request is asynchronous, application initialization will be completed first and likely result in race condition.
Most times when a need for $http in config appears, it should be performed in route resolver. If the response contains information that should be used to configure service providers and should be available in config block, it should be fetched prior to application bootstrap - in fact, there should be two applications, as shown here.
My app is following John Papa's styleguide for AngularJS applications:
The styleguide emphasizes using a strongly modular approach to the design of the app. My question is about multiple configurations and their effect on shared services.
Suppose I have a main module like this:
angular.module("app", ["app.feature1"])
.config(function() {
// do some configuration here
console.log("app configured");
});
And a feature module that configures a shared angular service, let's say the $http service:
angular.module("app.feature1", [])
.config(function($http) {
// configure the $http service
console.log("feature1 configured");
});
Is my understanding correct, that the configuration by "feature1" will carry over to the main module, since the $http service is a singleton and therefore shared across modules? Or do I have to configure the $http service in the main module instead, because each module has it's own $http service instance?
Edit: I can confirm that dependency configs are carried over and are executed first. See David's jsfiddle example.
As a matter of best practice, you should configure services as early as possible, which is typically your main module (the app root), and preferably only once to avoid overlapping changes.
Since $http is a singleton (as you mentioned), any changes via configuration will be propagated throughout the application every time you inject $http.
It's also worth mentioning that configuration to services is First In First Out, meaning that if you have two configuration changes, the last-accessed configuration will be the one that is persisted to the service since the previous configuration will be overwritten if they are changing identical components of the service.
In your case, yes, the change to $http in your module will be extended to your main application and any other modules using $http.
Finally, in light of the comments, child dependency configs are resolved before parent configs, as demonstrated by this simple fiddle:
http://jsfiddle.net/maqzo6fv/
HTML:
<div ng-app="app"></div>
JS:
angular.module("app", ["app.feature1"])
.config(function() {
alert('main config');
});
angular.module("app.feature1", [])
.config(function() {
alert('child config');
});
The child config will call alert before main on every load.
I'm using AngularFire to create a web app. Several of my controllers use a lot of the same functions to access the data in Firebase, so I am trying to write a service so that I don't have to rewrite the same functions for every controller. The problem is that I can't seem to get the Firebase dependency into the service. I'm using the following code:
angular.module("myApp", ["firebase","ngDraggable"])
.factory("GetData",['$firebase','FirebaseConn',function($firebase,FirebaseConn){
$firebase(new Firebase("https://XXXX.firebaseio.com/")).$asObject().$bindTo(scope, "firebaseData");
return {
};
}]);
But when I try to run this, I get the following error:
Unknown provider: FirebaseConnProvider <- FirebaseConn
I am able to access Firebase through my controllers, so it's not a problem connecting to firebase.js or angularfire.js.
How should I inject Firebase into my service so I can access the data in all of my controllers? Or, is there a better way to go about this? I'm rather new to Angular so if there's a better way to share functions between my controllers I'm all ears.
You inject them precisely the same way that you do in Controllers and Directives.
This is a common error in AngularJS, and it means you're injecting something that isn't injectable. It almost always means either you missed a dependency (probably not in this case) or that you're asking for something that doesn't exist in the first place.
This is almost certainly your problem. You're asking for firebase and getting it, but it can't find FirebaseConn. What is that, some variable of yours that you're using to track your connection? Because you aren't using it, and the AngularFire docs I just looked at don't, either.
Consider something more like the following:
angular
.module("myApp", ["firebase", "ngDraggable"])
.service("firebaseManager",['$firebase', function($firebase) {
var ref = new Firebase("https://XXXX.firebaseio.com/"),
sync = $firebase(ref);
this.getData = function() {
return sync.$asObject();
};
});
Obviously, customize this to suit. Two comments:
You probably do want a service instead of a factory. This is a common point of confusion when you first start using AngularJS. You only need a factory if you plan to get involved in the instantiation of the service in some way. A service is just a shortcut form of a factory with the most common usage - the one you probably want.
You will now inject this service firebaseManager into your controllers. When you do, they will be able to call firebaseManager.getData() and any other methods you define. firebaseManager will be a singleton, so all of this will go through one common Firebase connection.
I just started to learn Angularjs 2 days ago. A question have confused me for all the 2 days.
I need to make a http request to the server to get some data when the app start, but I cannot find the suitable moment to do this.
I've tried to make a controller, which calls $http.get(). But It doesn't work. It seems that the controller won't be instantiated if it's never used in the html (not sure about this).
I also tried to find other ways, but I only found $http which is used for http request. And $http only appears in the controller.
Maybe I need use other Angularjs methods? Or, I should do the instantiate action manually?
Something like:
angular.module('yourApp').run(['$rootScope', '$http', function ($rootScope, $http) {
// do stuff here
}]);
From the documentation:
Run Blocks
Run blocks are the closest thing in Angular to the main method. A run block is the code which needs to run to kickstart the application. It is executed after all of the service have been configured and the injector has been created. Run blocks typically contain code which is hard to unit-test, and for this reason should be declared in isolated modules, so that they can be ignored in the unit-tests.
Some of my routes needs functionality from external JS. I don't want to load them all at once since those JS are needed only in certain routes (e.g. /upload needs some JS for photo uploading, /photos needs another JS for lightbox, /funny needs JS for animation stuff, etc).
What's the best practice for lazily loading those external JavaScripts?
Those routes can be accessed multiple times (e.g. user can go to /upload then /photos then /upload again)
In addition to what Alex has stated, if you will be lazy loading AngularJS artefacts such as controllers and directives, you would have to use the relevant provider to register them instead of the module API. Artefacts registered using the module API after the application has been bootstrapped, will not be available to the application. For example, you would define a lazy controller like this...
$controllerProvider.register('SomeLazyController', function($scope)
{
$scope.key = '...';
});
instead of this...
angular.module('app').controller('SomeLazyController', function($scope)
{
$scope.key = '...';
});
I have written a blog post detailing this as well as how to use the 'resolve' method that Alex speaks about, to implement lazy loading in AngularJS. http://ify.io/lazy-loading-in-angularjs/
The only way I know to handle cases like this is using the "resolve" method of a route. This method can be used to define a dependency to be loaded before the route's controller is instantiated. One of the different possible return types of this method is a promise. Thus you might use this to start loading your external JavaScript code asynchronously and return a promise that is resolved as soon as your external scripts are loaded.
The documentation for this can be found here: https://docs.angularjs.org/api/ngRoute/provider/$routeProvider in the "when" section.
#alex3683's answer is probably the correct AngularJS way, but I don't grasp the concept, so instead I make use of jQuery's getScript(). So, in CoffeeScript:
yourModule.factory 'foo', ->
$.getScript 'https://script-to-load', ->
# whatever you want to do once the script is loaded
And just call it from your controller. Since AngularJS services are lazy and singleton, this will only load the script once.