Angular2–不提供可注射服务

Question

我的angular2应用程序中有一个名为HttpClient的服务。该服务应该为应用程序发送到我的端点的每个请求添加一个授权标头。

import { Injectable }    from '@angular/core';
import { Headers, Http, Response, } from '@angular/http';
import { Router } from '@angular/router';
import { ErrorService } from '../../services/error/error.service'
@Injectable()
export class HttpClient {
    private token: string;
    private error: any;
    private webApi = 'http://localhost:8080/api/v1/';    // Url to web api
    constructor(
        private http: Http,
        private router: Router,
        private errorService: ErrorService) { }
    get(url: string): Promise<Response> {
        return this.http.get(this.webApi + url, this.createAuthorizationHeader())
                    .toPromise()
                    .catch((e) => this.handleError(e));
    }
    post(url: string, data: any): Promise<Response> {
        return this.http.post(this.webApi + url, JSON.stringify(data), this.createAuthorizationHeader())
                    .toPromise()
                    .catch((e) => this.handleError(e));
    }
    put(url: string): Promise<Response> {
        return this.http.get(this.webApi + url, this.createAuthorizationHeader())
                    .toPromise()
                    .catch((e) => this.handleError(e));
    }
    delete(url: string): Promise<Response> {
        return this.http.delete(this.webApi + url, this.createAuthorizationHeader())
                    .toPromise()
                    .catch((e) => this.handleError(e));
    }
    private handleError (error: any) {
        var status: number = error.status;
        if (status == 415) {
            this.errorService.setError(error);
        }
        let errMsg = (error.message)
            ? error.message
            : status
                ? `${status} - ${error.statusText}`
                : 'Server error';
        console.error(errMsg); // log to console instead
        return Promise.reject(errMsg);
    }
    private createAuthorizationHeader() {
        let headers = new Headers();
        headers.append('Content-Type', 'application/json');
        headers.append('Accept', 'application/json');
        if (localStorage.getItem('token'))
            this.token = localStorage.getItem('token');
        headers.append('Authorization', 'Bearer ' + this.token);
        return headers;
    }
}

此外，该服务正在为另一个名为ErrorService 的自定义服务设置错误

import { Injectable, EventEmitter }    from '@angular/core';
@Injectable()
export class ErrorService {
    error: any;
    public errorAdded$: EventEmitter<any>;
    constructor() {
        this.errorAdded$ = new EventEmitter();
    }
    getError(): any {
        return this.error;
    }
    setError(error: any) {
        alert('is not going to be called');
        this.error.error = error;
        this.errorAdded$.emit(error);
    }
}

这些服务将在我的主机上启动。ts

...
import { ErrorService }   from './services/error/error.service';
import { HttpClient }   from './services/http/http.service';
...
bootstrap(AppComponent, [
    appRouterProviders,
    HTTP_PROVIDERS,
    ErrorService,
    HttpClient,
    ....
]);

现在我想在我的头组件中显示这个错误。所以加班时发生了一个错误，这个错误将显示在我的标题中的一个单独的框中。

问题是我在HttpClient.handleError中调用的ErrorService.setError(error)方法甚至不会被激发。

Answer 1

.catch(this.handleError);

应该是

.catch((e) => this.handleError(e));

保留this.的范围其中(e)是参数列表

或者，您可以使用

.catch(this.handleError.bind(this));