Ik have this very strange behavior which I can’t explain. I have a ASPNET Core (2.1) API, just a standard API, no fancyness there.
And I’m building a front-end with Angular (7). This front-end is used to perform some CRUD actions on a certain entity.
I’ve got all required steps done in the backend service (the API runs and all endpoints are in place, CORS is set to allow everything). Also, I’ve got postman requests for every endpoint, with every request succeeding.
I’ve got a Redux (ngrx) store in Angular, also version 7 there.
Now when I perform get requests (it doesn’t matter if it’s a list or a single entity request), the request always succeeds. On POST. PUT and DELETE requests however, the request sometimes fails.
When I start a debug session on the backend, I see that the backend always succeeds, returning either 200, 201 or 204 depending on the request. Let’s take the PUT for example, always returns a 200 response with the new version of the entity in the body (formatted in JSON ofcourse).
Now this put-request SOMETIMES fails on the front-end, once again, the server always returns 200. If I make no data changes in the front-end, just keep sending the same request with the same headers and the same body, making the backend return the same (success) response with the same body, the front-end sometimes works fine, and sometimes throws an error.
I’m using rxjs 6.3.3
here is an example how I handle the service request in my redux effects :
@Effect()
updatedEntity$: Observable<Action> = this.actions$.pipe(
ofType<UpdatedEntity>(shortenedLinksActions.updatedEntity),
debounceTime(300),
switchMap((action) =>
this.service.put(action.dto).pipe(
map((response: EntityDto) => {
return new UpdatedEntitySuccess(response);
}),
catchError((response: HttpErrorResponse) => {
if (response.status === 0) {
return of(
new GeneralFailure(
'The backend service is not responding'
)
);
}
return of(new GeneralFailure(response.error));
})
)
)
);
Source: Angular
