Angular 5拦截-请求重复

问题描述

我在角度5中使用了带有HttpInterceptor的拦截器，而我的rxjs遇到了一个问题，其中所有http请求都重复了.

import { Router } from '@angular/router';
import { Injectable, ApplicationRef } from '@angular/core';
import { HttpEvent, HttpInterceptor, HttpHandler, HttpRequest, HttpResponse } from '@angular/common/http';
import { Observable } from 'rxjs/Rx';
import 'rxjs/add/observable/throw';
import 'rxjs/add/operator/catch';
import 'rxjs/add/observable/empty';
import { NgxSpinnerService } from 'ngx-spinner';
import { ErrorHandlingService } from '../../service/error-handling.service';

@Injectable()
export class ApiRequestInterceptor implements HttpInterceptor {

  private count: number = 0;

  constructor(
    private readonly spinner: NgxSpinnerService,
    private readonly router: Router,
    private readonly errorHandling: ErrorHandlingService,
    private readonly applicationRef: ApplicationRef) { }

  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    this.count++;

    if (this.count === 1) {
      this.spinner.show();
    }

    return next.handle(req)
      .catch((err: any) => {
        this.count--;
        return Observable.throw(err);
      }).do(event => {
        if (event instanceof HttpResponse) {
          this.count--;
          if (this.count === 0) this.spinner.hide();
        }
      });
  }
}

如您所见，我的应用程序正在使用具有不同组件和服务的httpclient发出请求，这些请求发生了两次.我尝试删除subscribe，所以它只执行do功能，而我的微调框永不停止.

有人对我应该做什么有任何建议吗?我认为我没有正确使用rxjs，但不确定是什么解决方法.

解决方案

您两次呼叫next.handle().只需返回第一个，而无需调用subscribe:

intercept(req: HttpRequest<any>,next: HttpHandler): Observable<HttpEvent<any>> {
    this.count++;

    if (this.count === 1) {
      this.spinner.show();
    }

    return next.handle(req)
      .catch((err: any) => {
        this.count--;
        return Observable.throw(err);
      }).do(event => {
        if (event instanceof HttpResponse) {
          this.count--;
          if (this.count === 0) setTimeout(this.spinner.hide());
        }
    });
}

I am using an interceptor with HttpInterceptor in angular 5 and I have a problem with rxjs where all my http requests are duplicated.

import { Router } from '@angular/router';
import { Injectable, ApplicationRef } from '@angular/core';
import { HttpEvent, HttpInterceptor, HttpHandler, HttpRequest, HttpResponse } from '@angular/common/http';
import { Observable } from 'rxjs/Rx';
import 'rxjs/add/observable/throw';
import 'rxjs/add/operator/catch';
import 'rxjs/add/observable/empty';
import { NgxSpinnerService } from 'ngx-spinner';
import { ErrorHandlingService } from '../../service/error-handling.service';

@Injectable()
export class ApiRequestInterceptor implements HttpInterceptor {

  private count: number = 0;

  constructor(
    private readonly spinner: NgxSpinnerService,
    private readonly router: Router,
    private readonly errorHandling: ErrorHandlingService,
    private readonly applicationRef: ApplicationRef) { }

  intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    this.count++;

    if (this.count === 1) {
      this.spinner.show();
    }

    return next.handle(req)
      .catch((err: any) => {
        this.count--;
        return Observable.throw(err);
      }).do(event => {
        if (event instanceof HttpResponse) {
          this.count--;
          if (this.count === 0) this.spinner.hide();
        }
      });
  }
}

As you can see, my app is making requests with httpclient with different components and services and those requests happen twice. I tried removing subscribe so it only does the do function but my spinner never stops.

Does anyone have any advice for what I should do? I think I am not using rxjs correctly but not sure what the fix is.

解决方案

You are calling next.handle() twice. Just return the first one, without calling subscribe:

intercept(req: HttpRequest<any>,next: HttpHandler): Observable<HttpEvent<any>> {
    this.count++;

    if (this.count === 1) {
      this.spinner.show();
    }

    return next.handle(req)
      .catch((err: any) => {
        this.count--;
        return Observable.throw(err);
      }).do(event => {
        if (event instanceof HttpResponse) {
          this.count--;
          if (this.count === 0) setTimeout(this.spinner.hide());
        }
    });
}

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