Angular 5 - Manipulating HttpErrorResponse's error property in HttpInterceptor

Question

I have custom error message body as JSON from rest api.

{  
   "status":400,
   "url":"/api/abc",
   "message":"Custom Error Message"
}

I want to get it as object in subscribe's error scope. I tried to convert it to an object after every response using HttpInterceptor. But HttpErrorResponse is read-only. How can I obtain this object in service?

intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
        return next.handle(request).do((event: HttpEvent<any>) => {}, (err: any) => {
            if (err instanceof HttpErrorResponse) {
                // Here trying convert to object from json
                err.error = <ErrorMessageBody>JSON.parse(err.error);
            }
        });
    }

Why are you trying to grab the error during an intercept, and not just during a response? — Syntactic Fructose, Mar 28 '18 at 19:37
Because I don't want to do the same process for every response — Ali Kurnaz, Mar 28 '18 at 19:43

score 1 · Accepted Answer · answered Apr 11 '18 at 20:07

1

err.error is already translated to JSON.

This worked for me with catch:

intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
    return next.handle(req)
        .catch((err: HttpErrorResponse) => {
            return Observable.throw(err.error);
        });
}

answered Apr 11 '18 at 20:07

Ali Kurnaz

57
8

I got mine working with your help. I had to use pipe due to a newer Angular version but it works, thanks :). "next.handle(request).pipe(catchError(...));" – samneric May 16 '20 at 23:58

Angular 5 - Manipulating HttpErrorResponse's error property in HttpInterceptor

1 Answers1