Angular2中的自定义Http服务。循环依赖错误
我已经创建了自定义Http服务来覆盖“request”方法,该方法在需要时更新每个请求上的令牌。但问题是我收到了“循环依赖”错误。知道怎么修理吗 自定义Http服务:Angular2中的自定义Http服务。循环依赖错误,angular,angular2-services,Angular,Angular2 Services,我已经创建了自定义Http服务来覆盖“request”方法,该方法在需要时更新每个请求上的令牌。但问题是我收到了“循环依赖”错误。知道怎么修理吗 自定义Http服务: import { Injectable } from '@angular/core'; import { Request, XHRBackend, RequestOptions, Response, Http, RequestOptionsArgs, Headers } from '@angular/http'; impo
import { Injectable } from '@angular/core';
import {
Request, XHRBackend, RequestOptions, Response, Http, RequestOptionsArgs, Headers } from '@angular/http';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/catch';
import 'rxjs/add/observable/throw';
import {UserService} from "../services/user.service";
@Injectable()
export class VodHttpService extends Http {
constructor(backend: XHRBackend, defaultOptions: RequestOptions, private userService : UserService ) {
super(backend, defaultOptions);
}
request(url: string | Request, options?: RequestOptionsArgs): Observable<Response> {
//adding access token to each http request before calling super(..,..)
let token = this.userService.token;
if (typeof url === 'string') {
if (!options) {
options = { headers: new Headers() };
}
if ( url != this.userService.PUBLIC_TOKEN_URL ) {
options.headers.set('Authorization', `Bearer ${token}`);
}
}
else {
if ( url.url != this.userService.PUBLIC_TOKEN_URL ) {
url.headers.set('Authorization', `Bearer ${token}`);
}
}
console.log(url);
return super.request(url, options)
.catch((error) => {
//if got authorization error - try to update access token
if (error.status = 401) {
return this.userService.updateToken()
.flatMap((result: boolean) => {
//if got new access token - retry request
if (result) {
return this.request(url, options);
}
//otherwise - throw error
else {
return Observable.throw(new Error('Can\'t refresh the token'));
}
})
}
else {
Observable.throw(error);
}
})
}
}
从'@angular/core'导入{Injectable};
进口{
来自“@angular/Http”的Request、XHRBackend、RequestOptions、Response、Http、RequestOptionsArgs、Headers};
从“rxjs/Observable”导入{Observable};
导入“rxjs/add/operator/catch”;
导入“rxjs/add/observable/throw”;
从“./services/user.service”导入{UserService};
@可注射()
导出类VodHttpService扩展了Http{
构造函数(后端:XHRBackend,defaultOptions:RequestOptions,私有userService:userService){
超级(后端,默认选项);
}
请求(url:string |请求,选项?:RequestOptionsArgs):可观察{
//在调用super(..)之前向每个http请求添加访问令牌
让token=this.userService.token;
如果(url的类型=='string'){
如果(!选项){
选项={headers:newheaders()};
}
如果(url!=this.userService.PUBLIC\u令牌\u url){
options.headers.set('Authorization','Bearer${token}`);
}
}
否则{
if(url.url!=this.userService.PUBLIC\u TOKEN\u url){
set('Authorization','Bearer${token}`);
}
}
console.log(url);
返回super.request(url、选项)
.catch((错误)=>{
//如果获得授权错误-尝试更新访问令牌
如果(error.status=401){
返回这个.userService.updateToken()
.flatMap((结果:布尔)=>{
//如果获得新的访问令牌-重试请求
如果(结果){
返回此.request(url、选项);
}
//否则-抛出错误
否则{
return Observable.throw(新错误('Can't refresh the token'));
}
})
}
否则{
可观察的投掷(错误);
}
})
}
}
我的singleton用户服务看起来像:
import {Component, Injectable, Injector} from '@angular/core';
import {Http} from "@angular/http";
import {Observable} from "rxjs";
import {environment} from "../../environments/environment";
@Injectable()
export class UserService {
public token : string;
public PUBLIC_TOKEN_URL = environment.token_url;
constructor (private _http: Http) { }
updateToken() : Observable<boolean> {
let url = this.PUBLIC_TOKEN_URL;
return this._http.get(url).map( res => {
// return res.json();
if (typeof res.json().access_token !== 'undefined'){
this.token = res.json().access_token;
return true;
} else {
return false;
}
});
}
}
从“@angular/core”导入{Component,Injectable,Injector};
从“@angular/Http”导入{Http};
从“rxjs”导入{observeable};
从“../../environments/environment”导入{environment}”;
@可注射()
导出类用户服务{
公共令牌:字符串;
public-public\u-TOKEN\u-URL=environment.TOKEN\u-URL;
构造函数(私有http:http){}
updateToken():可观察{
让url=this.PUBLIC\u TOKEN\u url;
返回此。_http.get(url.map)(res=>{
//返回res.json();
if(typeof res.json().access_token!=“未定义”){
this.token=res.json().access_token;
返回true;
}否则{
返回false;
}
});
}
}
我知道使用Injector解决问题的方法在哪里,但我认为这是一种丑陋的方法。自定义VodHttpService的提供商定义不正确。应该是这样的:
export function vodHttpFactory(backend: XHRBackend, options: RequestOptions, userService: UserService) {
return new VodHttpService(backend, options, userService);
}
@NgModule({
// other stuff
providers: [
UserService,
{
provide: VodHttpService,
useFactory: vodHttpFactory,
deps: [XHRBackend, RequestOptions, UserService]
}
]
})
请注意,
vodHttpFactory
函数是这样编写的,以便在需要时与AOT兼容。您将UserService
注入到一个http服务中,这在我看来是不正确的。正确的方法是抛弃http,使用新的HttpClient替换它,并编写一个拦截器。您是否也可以在向提供商注册这两个服务的地方发布代码?(我假设是在模块定义中)@AndreiMatracaru,它看起来是这样的:`providers:[UserService,{provide:Http,useClass:VodHttpService}`