CODEWITHSUNDEEP
angularangular6angular-http-interceptorsangular-httpclient
sarahwc5
sarahwc5

Reputation: 401

Angular httpClient interceptor error handling

after reading the documentation on angular about http client error handling, I still don't understand why I don't catch a 401 error from the server with the code below:

export class interceptor implements HttpInterceptor {
    intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
        console.log('this log is printed on the console!');

        return next.handle(request).do(() => (err: any) => {
            console.log('this log isn't');
            if (err instanceof HttpErrorResponse) {
                if (err.status === 401) {
                    console.log('nor this one!');
                }
            }
        });
    }
}

on the console log, I also get this:

zone.js:2969 GET http://localhost:8080/test 401 ()

core.js:1449 ERROR HttpErrorResponse {headers: HttpHeaders, status: 401, statusText: "OK", url: "http://localhost:8080/test", ok: false, …}

Upvotes: 11

Views: 32919

Answers (5)

Muhammed Moussa
Muhammed Moussa

Reputation: 5195

here some example I'm using:

export class ErrorHandlerInterceptor implements HttpInterceptor {

    intercept(
        request: HttpRequest<any>,
        next: HttpHandler
    ): Observable<HttpEvent<any>> {
        const loadingHandlerService = this.inej.get(LoadingHandlerService);
        const errorHandlerService = this.inej.get(ErrorHandlerService);

        return next.handle(request)
            .pipe(
                catchError(err => {
                    loadingHandlerService.hideLoading();
                    if (err instanceof HttpErrorResponse) { errorHandlerService.handleError(err) }
                    return new Observable<HttpEvent<any>>();
                })
            );
    }

    constructor(private inej: Injector) { }
}

Upvotes: 0

Titukedo
Titukedo

Reputation: 950

Your error handler needs to return a new Observable<HttpEvent<any>>()

return next.handle(request)
    .pipe(catchError((err: any) => {
        console.log('this log isn't');
        if (err instanceof HttpErrorResponse) {
            if (err.status === 401) {
                console.log('Unauthorized');
            }
        }

      return new Observable<HttpEvent<any>>();
    }));

Upvotes: 12

Oleksii
Oleksii

Reputation: 59

It is off top, but Angular has better opportunity handle errors than interceptor. You can implement your own ErrorHandler. https://angular.io/api/core/ErrorHandler

Upvotes: 0

Amit Chigadani
Amit Chigadani

Reputation: 29705

You should catch an error using catchError

return next.handle(request)
      .pipe(catchError(err => {
        if (err instanceof HttpErrorResponse) {
            if (err.status === 401) {
                console.log('this should print your error!', err.error);
            }
        }
}));

Upvotes: 10

Daniel Caldera
Daniel Caldera

Reputation: 1119

You must pass the argument value to the do function of the stream, not create a new function inside it:

return next.handle(request)
    .do((err: any) => {
        console.log('this log isn't');
        if (err instanceof HttpErrorResponse) {
            if (err.status === 401) {
                console.log('nor this one!');
            }
        }
    });

Upvotes: 1

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