How to create an Http instance WITHOUT using constructor DI? (RC.5+) [duplicate]

Answer 1

Just look at the source for HttpModule. You'll see all the providers required to create the Http. Most of those providers were what were in the now removed HTTP_PROVIDERS

export function _createDefaultCookieXSRFStrategy() {
  return new CookieXSRFStrategy();
}

export function httpFactory(xhrBackend: XHRBackend, requestOptions: RequestOptions): Http {
  return new Http(xhrBackend, requestOptions);
}

@NgModule({
  providers: [
    {provide: Http, useFactory: httpFactory, deps: [XHRBackend, RequestOptions]},
    BrowserXhr,
    {provide: RequestOptions, useClass: BaseRequestOptions},
    {provide: ResponseOptions, useClass: BaseResponseOptions},
    XHRBackend,
    {provide: XSRFStrategy, useFactory: _createDefaultCookieXSRFStrategy},
  ],
})
export class HttpModule {
}

Just add everything in the above providers to the array you pass to ReflectiveInjector.resolveAndCreate.

If your goal is to get the Http before bootstrap, there's another little thing you need to take care of, which is the CookieXSRFStrategy. It will not work prior to bootstrapping, as it is dependendent on some platform browser stuff. You can just replace it with a noop, as mentioned in this post

Answer 2

Finally found an answer.

You can use Injector to get dependency as shown below.

service.ts

import { Injectable,Injector } from '@angular/core';
import {Http} from '@angular/http';

@Injectable()
export class Service{
    constructor(private injector:Injector){}

    display(){

        this.http=this.injector.get(Http);   //<<<<------here the magic happens

        console.log(this.http);
        return this.http.get('user.json').map(res => {return res.json()}).toPromise();
    } 
}

If you still have any doubt, you can check this working plunker made in Angular2.0.0 :
https://plnkr.co/edit/eWLB2BaL66pnJ7SC6qAL?p=preview