依赖注入不会加载所有参数 [英] Dependency injection does not load all params
问题描述
我目前正在尝试为我的angular2应用创建自定义XHRBackend
.我想用401 http响应代码(未授权)捕获所有http响应,以在登录页面上重定向用户.但这是我的问题: DI无法将Router
加载到我的自定义后端中.
I'm currently trying to create a custom XHRBackend
for my angular2 app. I want to catch all http responses with a 401 http response code (unauthorized) to redirect the user on the login-page. But here comes my problem: the DI is not able to load the Router
in my custom-backend.
@Injectable()
export class CustomXHRBackend extends XHRBackend {
constructor(
_browserXHR: BrowserXhr,
_baseResponseOptions: ResponseOptions,
_xsrfStrategy: XSRFStrategy,
private router : Router) {
super(_browserXHR, _baseResponseOptions, _xsrfStrategy);
console.log(router); // --> undefined
}
createConnection(request: Request) {
let xhrConnection = super.createConnection(request);
xhrConnection.response = xhrConnection.response.catch((error, caugth) => {
if(error.status === 401) {
//Do stuff with the new router
this.router.navigate(['/login']);
}
return Observable.throw(caugth);
});
return xhrConnection;
}
}
由于定义了前三个参数,因此DI似乎仍然使用XHRBackend
的元数据.
It seems like the DI still uses the metadata of the XHRBackend
, because the first 3 params are defined.
我创建了一个plunkr,它演示了此问题: http://plnkr.co/edit/44imf9KpE06cIyQ395sg?p =预览
I created a plunkr, that demonstrates this issue: http://plnkr.co/edit/44imf9KpE06cIyQ395sg?p=preview
注意:
plunkr是基于angular2路由器示例的,不幸的是我没有足够的时间来创建一个较小的.
重要文件是custom.backend.ts
,也许是main.ts
.
The plunkr is based on the angular2 router example, unfortunately I had not enough time to create a smaller one.
The important files are custom.backend.ts
and perhaps main.ts
.
有一个主意,为什么会这样?
Has someone an idea, why this is happening?
推荐答案
为此,我将扩展Http
类.这是一个示例:
For this, I would extend the Http
class instead. Here is a sample:
@Injectable()
export class CustomHttp extends Http {
constructor(backend: ConnectionBackend, defaultOptions: RequestOptions) {
super(backend, defaultOptions);
}
request(url: string | Request, options?: RequestOptionsArgs): Observable<Response> {
console.log('request...');
return super.request(url, options).catch(res => {
// do something
});
}
get(url: string, options?: RequestOptionsArgs): Observable<Response> {
console.log('get...');
return super.get(url, options).catch(res => {
// do something
});
}
}
并按如下所述进行注册:
and register it as described below:
bootstrap(AppComponent, [HTTP_PROVIDERS,
new Provider(Http, {
useFactory: (backend: XHRBackend, defaultOptions: RequestOptions) => new CustomHttp(backend, defaultOptions),
deps: [XHRBackend, RequestOptions]
})
]);
修改
我认为您需要使用useFactory
明确提供参数:
I think you need to provide explicitly parameters using useFactory
:
import {provide} from '@angular/core';
import {Router} from '@angular/router';
import { bootstrap } from '@angular/platform-browser-dynamic';
import { AppComponent } from './app.component';
import { APP_ROUTER_PROVIDERS } from './app.routes';
import {HTTP_PROVIDERS, Http,RequestOptions, XHRBackend, XSRFStrategy, BrowserXhr} from '@angular/http';
import {CustomXHRBackend} from './custom.backend';
bootstrap(AppComponent, [
APP_ROUTER_PROVIDERS,
HTTP_PROVIDERS,
provide(XHRBackend, {
useFactory: (browserXHR: BrowserXhr, requestOptions: RequestOptions, xsrfStrategy: XSRFStrategy, router: Router) => {
return new CustomXHRBackend(browserXHR, requestOptions, xsrfStrategy, router);
},
deps: [BrowserXhr, RequestOptions, XSRFStrategy, Router]
})
]);
请参阅以下代码: http://plnkr.co/edit/JK3q5nspZ434AeJJsUeJ?p=preview .
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