How can I inject the request or the execution context in a service without the help of controller without any performance issues?
The docs make it very clear that to pass the request to a service you can use a REQUEST scoped service with #Inject(REQUEST) or you can get the request in the controller via #Req() and pass that to the service method.
There is nestjs-cls which may be helpful as well, but generally, you either pass it on or you take the performance hit for REQUEST scoping the provider.
Related
I have an angular application. From frontend I can set some value. This value is something like config, which can be changed.
It is simple string variable. How to attach this config to each REST request ?
I ask mainly about approach.
Maybe pass it via headers is good idea ?
For angular 1.x, write an Interceptor:
For purposes of global error handling, authentication, or any kind of
synchronous or asynchronous pre-processing of request or
postprocessing of responses, it is desirable to be able to intercept
requests before they are handed to the server and responses before
they are handed over to the application code that initiated these
requests
For angular 2.x / 4.x, RequestOptions should be the key to solve your problem. Set base url for angular 2 http requests
I'm using angular2, my solution is create a Service and inject "Http" dependency, then write two methods "get", "post", these methods add an entry to header before calling "Http", in other component / service, I just inject this Service class, then call its "get" or "post".
Your code should be somewhat like this If your working in angular 1.3 or less
The data should be sent as body data to server
var basecall = Restangular.all('url');
bascall.post($scope.config).then(function(data){
})
My apps are using many web services on the intranet, and url-s for those depend on the server environment.
My apps are hosted on IIS, which adds an HTTP response header like this: Environment: DEV, so every web app knows in which server environment it is running, and thus which intranet servers it must use to call all the services.
Each of my angular apps uses a service that issues a simple GET against the app's own root just to get any response with the environment name in it, and set configuration accordingly.
Question:
How should an angular app implement such a service that would execute as the very first thing in the application, and make sure that while it is getting that first response, nothing in the app tries to execute an HTTP request against other services, or even try to use any configuration provided by my environment service?
Is there a way to implement such a service in angular that could block every other service / factory in the application till it is done initializing itself?
I have many other services in the app, and none of them really know what to do till my environment service has finished its initialization.
UPDATE
Looking at it from another angle.... is it possible to implement such an interceptor in angular that could do the following?:
execute an HTTP request and block the app's execution till it gets a response
make information from the response available throughout the app as a service/factory/config.
Angular lifecycle could be one solution. Using the angular.config() phase you could peek at the headers of the HTTP service.
Create a factory called 'httpInterceptor'
function httpInterceptors(siteConfig, $q, $injector) {
return {
response: function(data, status, headers) {
siteConfig.setEnvironment(headers['Environment']);
return data;
}
};
)
Then in angular.config()
$httpProvider.interceptors.push('httpInterceptor');
If you truly want to block the other option is to use UI router resolve property to block routes loading until the request has been made https://github.com/angular-ui/ui-router/wiki you can add the resolve method to the root state.
Resolve
You can use resolve to provide your controller with content or data that > is custom to the state. resolve is an optional map of dependencies which > should be injected into the controller.
If any of these dependencies are promises, they will be resolved and converted to a value before the controller is instantiated and the $stateChangeSuccess event is fired.
I am currently building a dashboard page with multiple widgets. Those widgets retrieve their data with REST calls ($resource). A few widgets make similar calls and I don't want to DDOS our server so I am looking for a way to make a call only once and resolve all similar requests with the same response.
Since I am restricted to using POST requests only, I cannot use the cache option that $resource offers. This seems to be doing exactly what I want but only for GET requests.
I was thinking along the lines of using a http interceptor to queue similar POST requests, fire only one of them and resolving them all when the first one gets its response.
However, I cannot seem to put the pieces together so any help is appreciated. I am open to other options.
Kind regards,
Tim
Services in AngularJS are singletons, so a solution would be to store the response in the service, as a variable. Then next time you'll do the request, previously check if the variable is null, if it's not you wrap it in a promise and returned it. If it's null, then you do the request, and store the response for the next call.
You can also either use this in your request service or in your interceptor service.
I hope I helped !
Refactor your widgets to depend on a service (singleton).
This service should either poll the server via XHR, or get server push via websocket for updates.
If polling, look into server side caching and etags.
I'm searching a solution but it's always the same and she's not correpond to my problem.
I have a lot of route element but for all routes with different controller I need to know if the user is authenticate or not. If yes, I have a token from an api and if no, I have a token too. So I need to have a token from an api when I load all controllers.
So I don't want to make a resolve for each "when()", I don't want to ddos the API so I search a system like this with
app.run(['Auth', function(Auth){
// Call my service & waiting his resolve
// When resolved, continue the init
}]);
So how can I make a resolve system with my "Auth" service on the run() ?
Make a service where you will have variable with status of authentication, inject this service in all controllers and in each controller call method of that service. Inside that method check variable with authentication status and only if authentication request was not yet send - send it (and set variable to status sent).
I'm trying to fetch data from a web API via Angular $resource service. The service exposes JSONP interface, but does not allow setting the callback name. Everything works well, my requests goes out, the data returns, the script is injected and then it fails because the callback function is not defined.
Angular documentation is very sparse on this, but it seems that the default callback function Angular sets up is: JSON_CALLBACK, and there's no info how to change that so that it matches the function returned by the foreign API.
Thanks.
I don't think that there is any provision to override that callback.
$resource is high level Restful api based on $http service.
You can use $http apis which returns http promise object and letting you write your success callback wherein you can process data returned from ajax request.
e.g. http://docs.angularjs.org/api/ng.$http#jsonp