typescript - HTTP request in an interval doesn't work Angular 10

Question

I'm working on Angular 10 with function of checking connectivity by keep sending a request to the server every 5 seconds.

The problem is the request doesn't really sent out, it just keep console.warn every 5 seconds.

The problem only occurs when response responded with status 200, if responded with status 404, it works. Once it responded with status 200, it won't send any HTTP request in every 5s and just print out the previous http request's data.

PS: I'm testing on localhost server

Here is my code

checkConnection(): Subscription {
    return interval(2000)
      .subscribe(
        x => {
          this.httpService.testConnectivity().subscribe(
            data => console.warn(`Success: ${data}`),
            error => console.warn(`Error: ${error}`),
            () => console.warn("Completed")
          )
        }
      );
}

The testConnectivity function as below

testConnectivity(): Observable<any> {
    if (isPlatformBrowser(this.platformId)) {
      return this.http
        .get(`${this.url}/api/testconnection`, { observe: 'response' })
        .pipe(
          catchError(this.handleError)
        );
    }
  }

question from:https://stackoverflow.com/questions/66061888/http-request-in-an-interval-doesnt-work-angular-10

Answer 1

I found the problem. The problem is the HTTP request was cached by the browser.

In order to making a refresh request. Simply add ?x where x is some unique number after the url (Eg: http://localhost:3000/api/testconnection?0) on every request.