Class: Router

workbox-routing.Router

class   static

Version     v2.1.3

The Router takes one or more Routes and allows you to apply that routing logic to determine the appropriate way of handling requests inside of a service worker.

It also allows you to define a "default" handler that applies to any requests that don't explicitly match a Route, and a "catch" handler that responds to any requests that throw an exception while being routed.

You can use the handleRequest() method to pass a FetchEvent through the router and ultimately get a "routed response" back. If you'd like this to be handled automatically for you, calling addFetchListener() will cause the Router to respond to fetch events.

If a request matches multiple routes, precedence will be given to the last-registered route.

Constructor

Router

new Router()

Constructs a new Router instance, without any registered routes.

Example

// The following example sets up two routes, one to match requests with
// "assets" in their URL, and the other for requests with "images", along
// different runtime caching handlers for each.
// Both the routes are registered with the router, and any requests that
// don't match either route will be handled using the default NetworkFirst
// strategy.
// "If a request matches both routes, the last route will be used to handle 
// the request, in this case, the "images" handler would take precedence.
const assetRoute = new RegExpRoute({
  regExp: /assets/,
  handler: new workbox.runtimeCaching.StaleWhileRevalidate(),
});
const imageRoute = new RegExpRoute({
  regExp: /images/,
  handler: new workbox.runtimeCaching.CacheFirst(),
});

const router = new workbox.routing.Router();
router.addFetchListener();
router.registerRoutes({routes: [assetRoute, imageRoute]});
router.setDefaultHandler({
  handler: new workbox.runtimeCaching.NetworkFirst(),
});

Methods

addFetchListener

addFetchListener() returns boolean

This will register a fetch event listener on your behalf which will check the incoming request to see if there's a matching route, and only respond if there is a match.

Returns

boolean Returns true if this is the first time the method is called and the listener was registered. Returns false if called again, as the listener will only be registered once.

Example

const imageRoute = new RegExpRoute({
  regExp: /images/,
  handler: new CacheFirst(),
});

const router = new Router();
router.registerRoute({route: imageRoute});
router.addFetchListener();

handleRequest

handleRequest(input) returns (Promise containing Response or undefined)

This can be used to apply the routing rules to generate a response for a given request inside your own fetch event handler.

Parameter
input	Object Values in input have the following properties: Parameter event FetchEvent The event passed in to a fetch handler.

Returns

(Promise containing Response or undefined) Returns a promise for a response, taking the registered routes into account. If there was no matching route and there's no defaultHandler, then returns undefined.

Example

const imageRoute = new RegExpRoute({
  regExp: /images/,
  handler: new CacheFirst(),
});

const router = new Router();
router.registerRoute({route: imageRoute});

self.addEventListener('fetch', (event) => {
  event.waitUntil((async () => {
    let response = await router.handleRequest({event});
    // Do something with response, and then eventually respond with it.
    event.respondWith(response);
  })());
});

registerRoute

registerRoute(input)

Registers a single route with the router.

Parameter
input	Object Values in input have the following properties: Parameter route module:workbox-routing.Route The route to register.

Example

router.registerRoute({
  route: new Route({ ... })
});

registerRoutes

registerRoutes(input)

Registers an array of routes with the router.

Parameter
input	Object Values in input have the following properties: Parameter routes Array of module:workbox-routing.Route An array of routes to register.

Example

router.registerRoutes({
  routes: [
    new RegExpRoute({ ... }),
    new ExpressRoute({ ... }),
    new Route({ ... }),
  ]
});

setCatchHandler

setCatchHandler(input)

If a Route throws an error while handling a request, this handler will be called and given a chance to provide a response.

Parameter
input	Object Values in input have the following properties: Parameter handler (function() or module:workbox-runtime-caching.Handler) This parameter can be either a function or an object which is a subclass of Handler. Either option should result in a Response that the Route can use to handle the fetch event. See handlerCallback for full details on using a callback function as the handler.

Example

router.setCatchHandler(({event}) => {
  if (event.request.mode === 'navigate') {
    return caches.match('/error-page.html');
  }
  return Response.error();
});

setDefaultHandler

setDefaultHandler(input)

An optional handler that's called by default when no routes explicitly match the incoming request.

If the default is not provided, unmatched requests will go against the network as if there were no service worker present.

Parameter
input	Object Values in input have the following properties: Parameter handler (function() or module:workbox-runtime-caching.Handler) This parameter can be either a function or an object which is a subclass of Handler. Either option should result in a Response that the Route can use to handle the fetch event. See handlerCallback for full details on using a callback function as the handler.

Example

router.setDefaultHandler({
  handler: new workbox.runtimeCaching.NetworkFirst()
});

unregisterRoute

unregisterRoute(input)

Unregisters a single route with the router.

Parameter
input	Object Values in input have the following properties: Parameter route module:workbox-routing.Route The route to unregister.

Example

const route = new RegExpRoute({ ... });
router.registerRoute({route});

// Later, if you no longer want the route to be used:
router.unregisterRoute({route});

unregisterRoutes

unregisterRoutes(input)

Unregisters an array of routes with the router.

Parameter
input	Object Values in input have the following properties: Parameter routes Array of module:workbox-routing.Route An array of routes to unregister.

Example

const firstRoute = new RegExpRoute({ ... });
const secondRoute = new RegExpRoute({ ... });
router.registerRoutes({routes: [firstRoute, secondRoute]});

// Later, if you no longer want the routes to be used:
router.unregisterRoutes({routes: [firstRoute, secondRoute]});