Angular2 http重试逻辑

2 回答

• 7

  这可以通过扩展 Http 类并利用 flatMap 之类的可观察运算符在Angular2中透明地完成 .

  以下是一些示例代码：

  if (hasTokenExpired()) {
    return this.authService
               .refreshAuthenticationObservable()
               .flatMap((authenticationResult:AuthenticationResult) => {
                  if (authenticationResult.IsAuthenticated == true) {
                       this.authService.setAuthorizationHeader(request.headers);
                    return this.http.request(url, request);
                  }
                  return Observable.throw(initialError);
      });
  }
  

  此代码必须集成到 Http 的自定义子类中：

  一种方法可以是扩展HTTP对象以拦截错误：

  @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
      });
    }
  }
  

  并按如下所述注册：

  bootstrap(AppComponent, [HTTP_PROVIDERS,
      new Provider(Http, {
        useFactory: (backend: XHRBackend, defaultOptions: RequestOptions) => new CustomHttp(backend, defaultOptions),
        deps: [XHRBackend, RequestOptions]
    })
  ]);
  

  有关详细信息，请查看以下问题：

  • Handling refresh tokens using rxjs

  • Angular 2 - How to get Observable.throw globally

  回复于 2024-04-30T13:14:07+08:00
• 1

  在我最近的项目中，我不得不做类似的事情shafihuzaib/cdp-ng-boilerplate并在这个问题上找到答案 . 我无法寻求上述建议的解决方案，因为它感觉很复杂而且不可取 . 所以我在实施之后回来留下我的解决方案 . 然而，不同的是，在我的情况下，我有两个这样的令牌 .

  因此，每个需要检查令牌有效性的请求都会在此函数中调用 .

  tokenValidatedRequest(func): Observable<any>{
      let returnObservable = new Observable();
  
      /**
       * 1. check for auth token expiry - refresh it, if necessary
       */
      if( parseInt(localStorage.getItem('AUTH_TOKEN_EXPIRY')) < (new Date()).valueOf() ){
          //auth expired
          this.refresh().subscribe(res => {
              //refreshed
              //this.postAuthSuccess(res);
  
               returnObservable = func();
  
          })
      }
      else{
          //auth not expired
  
         returnObservable = func();
  
      }
  
      return returnObservable;
  }
  

  这里最重要的是 func() 应该返回 Observable ，以便可以相应地使用它 .

  makeSomeHttpCall(){
     this.tokenValidatedRequest(()=>{
         return this.http.post(...);
     }). subscribe();
  }
  

  对于一个新人来说，这似乎有点复杂，但我相信它会更有效率 .

  在以下链接中，请忽略与此问题无关的详细信息，并关注建议的解决方案的使用 .

  Actual implementation of tokenValidatedRequest() in my project .

  tokenValidatedRequest(func , tqlCheck = false): Observable<any>{
      /**
       * Delegate the actual task. However return an Observable, so as to execute 
       * the callback function only when subscribed to..
       */
      //return Observable.create(obs => obs = (this.__tokenValidatedRequest(func, tqlCheck)));
  
      return this.__tokenValidatedRequest(func, tqlCheck);
  }
  private __tokenValidatedRequest(func, tqlCheck = false): Observable<any>{
      let returnObservable = new Observable();
  
      /**
       * 1. check for auth token expiry - refresh it, if necessary
       * 2. after step 1 - check for TQL token expiry (if tqlCheck is true) - refresh it, if necessary
       * 3. 
       */
      if( parseInt(localStorage.getItem('AUTH_TOKEN_EXPIRY')) < (new Date()).valueOf() ){
          //auth expired
          this.refresh().subscribe(res => {
              //refreshed
              this.postAuthSuccess(res);
  
              if(tqlCheck &&  localStorage.getItem("TQL_TOKEN_EXPIRY") &&
                      parseInt(localStorage.getItem("TQL_TOKEN_EXPIRY")) < (new Date()).valueOf()
                 ){
  
                  this.activateUser().subscribe(res => {
                      //TQL token subscribed 
                      returnObservable = func();
                  })
              }
              else{
                  // Probably not a TQL request
                  returnObservable = func();
              }
          })
      }
      else{
          //auth not expired
  
          //check if tql token has expired
          if(tqlCheck &&  localStorage.getItem("TQL_TOKEN_EXPIRY") &&
                      parseInt(localStorage.getItem("TQL_TOKEN_EXPIRY")) < (new Date()).valueOf()
                 ){
  
                  this.activateUser().subscribe(res => {
                      //TQL token subscribed 
                      returnObservable = func();
                  })
              }
              else{
                  // Probably not a TQL request or none of the tokens expired
                  returnObservable = func();
              }
      }
  
      return returnObservable;
  }
  

  How it is used in other services!

  getAllParkingSpaces() : Observable<any> {
      let query = {
          Query: {
              ....
          }
      };
  
      return this.authService.tokenValidatedRequest(()=>{
          return this.api.post( CONFIG.api.engineUrl + 'devices/parking', query);
      }, true);
  }
  

  How I finally subscribe to it!

  this.realTimeParkingService.getAllParkingSpaces().subscribe( r => {
    this.parkingSpaces = r;
  });
  

  回复于 2024-04-30T13:14:07+08:00