Question

我正在使用扩展的HttpClass，以便我可以动态应用标头和url路径。这就是它的样子：

app.http.ts

export enum Type {
  PREAUTH = 0,
  AUTH = 1,
  PRINTER = 2,
  TERMINAL = 3
}

@Injectable()
export class AppHttp extends Http {
  private typesOn: Array<any> = [false, false, false, false];

constructor(backend: ConnectionBackend, defaultOptions: RequestOptions) {
    super(backend, defaultOptions);
    this.presetPetition(Type.AUTH);
}

presetPetition(type: number) {
    this.typesOn.forEach(t => (t = false));
    this.typesOn[type] = true;
}

request(url: string | Request, options?: RequestOptionsArgs): Observable<Response> {
    return super.request(url, options);
}

get(url: string, options?: RequestOptionsArgs): Observable<Response> {
    return super.get(this.updateUrl(url), this.getRequestOptionArgs(options));
}

private updateUrl(req: string) {
  if (this.typesOn[Type.AUTH]) {
    return environment.apiURL + req
  } else {
    return req
  }
}

app.module.ts

providers: [
 AppHttp,
  {
    provide: Http,
    useFactory: httpFactory,
    deps: [XHRBackend, RequestOptions]
  }
]

http.factory.ts

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

当我尝试更改http请求的类型时，我将AppHttp导入组件/服务，并在我的http请求之前调用 presetPetition（）。

我得到No Provider for Backend Connection。所以我理解不能进行冗余的提供程序导入（Http和AppHttp），这必定是错误。

如何在扩展类中访问公共函数？或者我的方法是错的？

Answer 1

这违反了角度的编码标准。仅为URL集和crud操作创建API服务，并且为身份验证扩展HTTP服务。

对于常见的API：

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

import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/map';

@Injectable()
export class BaseService {

  private headers = new Headers({ 'Content-Type': 'application/json', 'charset': 'UTF-8' });
  private options = new RequestOptions({ headers: this.headers });

  constructor(private http: Http) { }

  // Get all
  getAll(url: any): Observable<any> {
    return this.http.get(url).map(res => res.json());
  }

  // Count all
  count(url: any): Observable<any> {
    return this.http.get(url).map(res => res.json());
  }

  // add
  add(url: any, entity: any): Observable<any> {
    return this.http.post(url, JSON.stringify(entity), this.options);
  }

  // Get by id
  getById(url: any, entity: any): Observable<any> {
    return this.http.get(url + `/${entity._id}`).map(res => res.json());
  }

  // Update by id
  editById(url: any, entity: any): Observable<any> {
    return this.http.put(url + `/${entity._id}`, JSON.stringify(entity), this.options);
  }

  // Delete by id
  deleteById(url: any, entity: any): Observable<any> {
    return this.http.delete(url + `/${entity._id}`, this.options);
  }

}

https://github.com/mdshohelrana/mean-stack/blob/master/client/app/shared/services/base.service.ts

对于扩展HTTP服务：

http://www.adonespitogo.com/articles/angular-2-extending-http-provider/

我认为这会对你有所帮助。

在扩展的HttpClass

1 个答案: