import { finalize, tap } from 'rxjs/operators';
import { MessageService } from '../message.service';
@Injectable()
export class LoggingInterceptor implements HttpInterceptor {
constructor(private messenger: MessageService) {}
intercept(req: HttpRequest, next: HttpHandler) {
const started = Date.now();
let ok: string;
// extend server response observable with logging
return next.handle(req)
.pipe(
tap(
// Succeeds when there is a response; ignore other events
event => ok = event instanceof HttpResponse ? 'succeeded' : '',
// Operation failed; error is an HttpErrorResponse
error => ok = 'failed'
),
// Log when response observable either completes or errors
finalize(() => {
const elapsed = Date.now() - started;
const msg = `${req.method} "${req.urlWithParams}"
${ok} in ${elapsed} ms.`;
this.messenger.add(msg);
})
);
}
}