302 redirects do not work in a service worker built with Google Workbox

问题

For having the "add tome homescreen" alert displayed, I want to integrate a service-worker and an offline capability of the application: When the user is offline, the app should simply display a special offline HTML file.

My service-worker looks like this:

importScripts('https://storage.googleapis.com/workbox-cdn/releases/3.1.0/workbox-sw.js');

const CACHE_VERSION = 1;

workbox.core.setCacheNameDetails({
  prefix: 'app',
  suffix: 'v' + CACHE_VERSION
});

workbox.routing.registerRoute(
    '/offline-page.html',
    workbox.strategies.networkFirst({
        networkTimeoutSeconds: 2,
        cacheableResponse: { statuses: [0, 200] },
    })
)

workbox.routing.registerRoute(
    ({ event }) => event.request.mode === 'navigate',
    ({ url }) =>
        fetch(url.href, { credentials: 'include', redirect: 'follow', }).catch(() => caches.match('/offline-page.html'))
)

But as soon as my application returns a 302 redirect (e.g. after login oder logout), I get the following warning message in the console:

The FetchEvent for "https://app.com" resulted in a network error response: a redirected response was used for a request whose redirect mode is not "follow".

and Google Chrome diplays an error page (ERR_FAILED) saying that the website can't be reached.

Does anyone have an idea how to fix this?

回答1:

You can adapt the "Provide a fallback response to a route" recipe in the docs to accommodate your particular restrictions.

There are a couple of different options for accomplishing this, but the cleanest would be to create your own network-only strategy (to mimic the fetch() that you're using in your example), chain .catch() to the end of it, and then use that as the handler when constructing a NavigationRoute.

That will give you a Route that you could then pass to workbox.routing.registerRoute().

// You're responsible for either precaching or
// explicitly adding OFFLINE_HTML to one of the caches.
const OFFLINE_HTML = '/offline-page.html';
const networkOnly = workbox.strategies.networkOnly();
const networkOnlyWithFallback = networkOnly().catch(() => caches.match(OFFLINE_HTML));
const route = new workbox.routing.NavigationRoute(networkOnlyWithFallback);
workbox.routing.registerRoute(route);

回答2:

This seems to do the trick:

const FALLBACK_URL = '/';

const networkOnly = workbox.strategies.networkOnly();

const route = new workbox.routing.NavigationRoute(({event}) => {
  return networkOnly.handle({event})
    .catch(() => caches.match(FALLBACK_URL));
});

workbox.routing.registerRoute(route);

来源：https://stackoverflow.com/questions/50074107/302-redirects-do-not-work-in-a-service-worker-built-with-google-workbox

标签

javascript

service-worker

progressive-web-apps

workbox