Angular 2 RC 5 Bootstrap custom HTTP class

问题

In Angular 2 RC 4 I have a class HttpLoading which extends the original Http of Angular2

I was able to use that in bootstrap without any issue using the below code:

bootstrap(AppComponent, [
    HTTP_PROVIDERS,
    provide(RequestOptions, { useClass: DefaultRequestOptions }),
    provide(Http, {
        useFactory: (backend: XHRBackend, defaultOptions: RequestOptions) => new HttpLoading(backend, defaultOptions),
        deps: [XHRBackend, RequestOptions]
    })
]).catch(err => console.error(err));

My DefaultRequest Options class

import { Injectable } from '@angular/core';
import { Headers, BaseRequestOptions } from '@angular/http';

@Injectable()
export class DefaultRequestOptions extends BaseRequestOptions {
    headers: Headers = new Headers({
        'Content-Type': 'application/json'
    });
}

My HttpLoading Class looks like this:

import { Http, RequestOptionsArgs, ConnectionBackend, RequestOptions, Response } from '@angular/http'
import { Injectable } from '@angular/core'
import {GlobalService} from './globalService';
import { Observable } from 'rxjs/Observable';

export class HttpLoading extends Http {

    constructor(backend: ConnectionBackend, defaultOptions: RequestOptions, private _globalService: GlobalService) {
        super(backend, defaultOptions);
    }

    get(url: string, options?: RequestOptionsArgs): Observable<any> {
        this._globalService.isLoading = true;
        return super.get(url, options)
            .map(res => {
                this._globalService.isLoading = false;
                return res.json();
            })
            .catch(this.handleError);
    }
}

With RC 5 I am not sure how do I migrate this portion of the code to NgModule providers list.

I have followed the migration guide and updated my NgModule to the following:

import { NgModule }       from '@angular/core';
import { BrowserModule  } from '@angular/platform-browser';
import { FormsModule, ReactiveFormsModule }   from '@angular/forms';
import { HttpModule }     from '@angular/http';
import { Http, HTTP_PROVIDERS, RequestOptions, XHRBackend } from '@angular/http';

import { DefaultRequestOptions } from './DefaultRequestOptions';
import { HttpLoading } from './http-loading';

import { routing }        from './app.routing';
import { AppComponent } from './components/app.component';


@NgModule({
    imports: [
        BrowserModule,
        FormsModule,
        ReactiveFormsModule,
        HttpModule,
        routing
    ],
    declarations: [
        AppComponent
    ],
    providers: [
        HTTP_PROVIDERS,
        { provide: RequestOptions, useClass: DefaultRequestOptions },
        {
            provide: Http,
            useFactory: (backend: XHRBackend, defaultOptions: RequestOptions, globalService: GlobalService) => new HttpLoading(backend, defaultOptions, globalService),
            deps: [XHRBackend, RequestOptions, GlobalService]
        }
    ],
    bootstrap: [AppComponent],
})
export class AppModule { }

But it still seems that its not properly added because in my component when I use http its still hitting the default http instead of my custom http service.

import { Component, OnInit } from '@angular/core';
import { Http } from '@angular/http';

@Component({
    templateUrl: '../../templates/home/home.html'
})
export class HomeComponent implements OnInit {

    constructor(private http: Http) {}

    ngOnInit() {
        this.http.get('/home')
            .subscribe((data) => {

            });
    }
}

Can anyone please guide?

回答1:

Since >=RC5 now you bootstrap an @NgModule class instead of your root componenet like this, read more on this RC4 => RC5 transition guide.

import { NgModule }       from '@angular/core';
import { HttpModule } from '@angular/http';
import { AppComponent }   from './app.component';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [HttpModule],  // no need for HTTP_DIRECTIVES
  providers: [
    {provide: RequestOptions, useClass: DefaultRequestOptions },
    {provide: Http, useFactory: (backend: XHRBackend, defaultOptions: RequestOptions) => new HttpLoading(backend, defaultOptions), deps: [XHRBackend, RequestOptions]}
  ],
  bootstrap: [AppComponent]
})
export class AppModule {}

platformBrowserDynamic().bootstrapModule(AppModule);

回答2:

Thank you so much everyone for your help, I was able to resolve the issue by removing

{ provide: RequestOptions, useClass: DefaultRequestOptions },

Which seems to be unnecassary with RC 5.

回答3:

I hade the same issue ... setting body to empty string solved it.

so get can receive a second parameter a "RequestOptions" ... be sure to set the body property to ''

Like so ...

.http.get(BaseService.apiUrl + api/someMethod, { body : '' }) ...

来源：https://stackoverflow.com/questions/38885912/angular-2-rc-5-bootstrap-custom-http-class