I would like to know whether we can create a provider in angularjs which will replace the $http operation .which means where we can use this provider in other modules where we can make use of these $http operation.
The reason why provider has to be taken is because we can configure the http parameters like the api path, request type .
Also can we have logging/exception handling mechanism inside the provider so that the modules(eg: any other factories) which inherit the provider wont need to do any extra logging/exception mechanisms.
Is there any way to have some loading screen using this provider when http requests are made ?
For the things you mentioned, you don't need another provider, because $http has the concept of interceptors.
Interceptors can specify different callbacks to be executed at different phases:
request (runs before any request is sent): It can modify the configuration (e.g. the request URL, method etc). It could also be used to show some loading message/animation (e.g. using some property on the $rootScope).
requestError (runs when there is an error before sending the request): It can be used for logging, recovering, exception handling.
response (runs after any response is received): It can be used for logging. It could also be used to hide the loading message/animation. (Don't forget to also handle this on response error.)
responseError (runs when there is an error regarding the response (e.g. bad request)): It can be used for logging, recovering, exception handling.
If interceptors do not cover your needs, you could use $provide's decorator to monkey-patch, augment or totally replace the $http service:
.config(function ($provide) {
$provide.decorator('$http', function ($delegate) {
var newHttp = $delegate; // or a totally new object
// ...monkey-patch newHttp or define new methods or whatever
return newHttp;
});
});
Related
I have an angular application. From frontend I can set some value. This value is something like config, which can be changed.
It is simple string variable. How to attach this config to each REST request ?
I ask mainly about approach.
Maybe pass it via headers is good idea ?
For angular 1.x, write an Interceptor:
For purposes of global error handling, authentication, or any kind of
synchronous or asynchronous pre-processing of request or
postprocessing of responses, it is desirable to be able to intercept
requests before they are handed to the server and responses before
they are handed over to the application code that initiated these
requests
For angular 2.x / 4.x, RequestOptions should be the key to solve your problem. Set base url for angular 2 http requests
I'm using angular2, my solution is create a Service and inject "Http" dependency, then write two methods "get", "post", these methods add an entry to header before calling "Http", in other component / service, I just inject this Service class, then call its "get" or "post".
Your code should be somewhat like this If your working in angular 1.3 or less
The data should be sent as body data to server
var basecall = Restangular.all('url');
bascall.post($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 implementing an angularjs service, which saves the data sent by an $http call in localStorage. In order to do that, I am using the request interceptor, so that whenever an http request is sent via $http, the data is saved in localStorage. Below is my code for the interceptor,
var OfflinkJs = angular.module('OfflinkJs', []);
OfflinkJs.factory('cacheInterceptor', function () {
var cacheInterceptor = {
request: function (config) {
// Here I am saving the config as a string in localstorage
return config;
}
};
return cacheInterceptor;
});
For above interceptor to work, I have to register it in the interceptors array of $httpProvider. I have done this to achieve that,
OfflinkJs.config(['$httpProvider', function ($httpProvider) {
$httpProvider.interceptors.push('cacheInterceptor');
}]);
PROBLEM
Now, when I use OfflinkJS module in another module, all the $http calls go through my interceptor. But I would like to make some requests sent by $http service use my interceptor while some other requests NOT.
Since $http service is a singleton, I cannot figure out how to use two instances of it in separate places of my application. Is there any way to achieve this?
I went through this question, but seems it really addresses the issue of Circular dependency
I need two instances of AngularJS $http service or what?
I check the URL in the interceptor and use that to filter out requests to other services. I set the base url for my service as a constant in my module, and then check against that. If the request isn't to the relevant service, it just passes through with no action.
But perhaps a better way would be to set up a data service instead of an interceptor. There are plenty of tutorials out there on data services.
I am writing an AngularJs app to test an API we developed. The app uses the $http object to make requests to the API. One of the asks is that after the call it's possible to review the raw HTTP (headers and bodies) Request/Response, similarly to what's available in Fiddler via Raw tabs.
Is it something that $http provides out of the box?
If not, it appears that the only challenge is gaining access to the actual request http headers. It's easy to get the response headers and request/response bodies, but not sure how to get the actual request headers.
Thanks.
If you are using $http service to make your API calls, you can use Interceptors to achieve what you want.
Here is what docs tell us about them:
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. The interceptors leverage the promise APIs to fulfill this need for both synchronous and asynchronous pre-processing.
You can find more in depth explanation in the official docs. For example, here.
Also, there are some questions about interceptors on this site. There are some examples of their usage for displaying loading screen in applications: here, here and, probably, somewhere else.
Hope, this helps.
Yes, AngularJs is wrapped around some JQuery or internally JQlite if JQuery is not present and written in Javascript and it provides some pre-defined services. A typical service looks like the following.
AngularJS docs: tutorial step 5
$ Prefix Naming Convention You can create your own services, and in
fact we will do exactly that in step 11. As a naming convention,
Angular's built-in services, Scope methods and a few other Angular
APIs have a $ prefix in front of the name.
The $ prefix is there to namespace Angular-provided services. To
prevent collisions it's best to avoid naming your services and models
anything that begins with a $.
If you inspect a Scope, you may also notice some properties that begin
with $$. These properties are considered private, and should not be
accessed or modified.
angular.module('myApp')
.factory('myService', function ($http, $injector) {
'use strict';
return $http.get('/endpoint')
.then(function () {
return $injector.get('endpoint');
}
.error(function () {
// handle error
}
};
})
Have a look a the image in AngularJS docs which shows a number of services with the $ prefix. Mostly, wrappers over service. It is reserved. More at FAQ.
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