CacheStorage.match()

The match() method of the CacheStorage interface checks if a given Request is a key in any of the Cache objects that the CacheStorage object tracks and returns a Promise that resolves to the matching Response.

Cache objects are searched by key insertion order.

Syntax

caches.match(request,{options}).then(function(response) {
  //do something with the request
});

Returns

a Promise that resolves to the matching Response.

Parameters

request

The Request you want to match.

options Optional

An object whose properties control how matching is done in the match operation. The available options are:

• ignoreSearch: A Boolean that specifies whether the matching process should ignore the query string in the url.  If set to true, the ?value=bar part of https://foo.com/?value=bar would be ignored when performing a match. It defaults to false.
• ignoreMethod: A Boolean that, when set to true, prevents matching operations from validating the Request http method (normally only GET and HEAD are allowed.) It defaults to false.
• ignoreVary: A Boolean that, when set to true, tells the matching operation not to perform VARY header matching. In other words, if the URL matches you will get a match regardless of whether the Response object has a VARY header or not. It defaults to false.
• cacheName: A DOMString that represents a specific cache to search within.

Note: If a cacheName is set in the options object and the cache does not exist, the promise will reject (cache.match() just resolves undefined if a matching response is not found.)

Examples

This code snippet is from the MDN sw-test example (see sw-test running live). Here we wait for a FetchEvent to fire. We construct a custom response like so:

1. Check whether a match for the request is found in the CacheStorage using CacheStorage.match. If so, serve that.
2. If not, open the v1 cache using open(), put the default network request in the cache using Cache.put and return a clone of the default network request using return response.clone() — necessary because put() consumes the response body.
3. If this fails (e.g., because the network is down), return a fallback response.

caches.match(event.request).then(function(resp) {
  return resp || fetch(event.request).then(function(r) {
    caches.open('v1').then(function(cache) {
      cache.put(event.request, r);
    });
    return r.clone();
  });
}).catch(function() {
  return caches.match('/sw-test/gallery/myLittleVader.jpg');
});

Specifications

Browser compatibility

• [1] The options parameter only supports ignoreSearch, and cacheName. 
• [2] Service workers (and Push) have been disabled in the Firefox 45 Extended Support Release (ESR.)

See also

• Using Service Workers
• Cache
• WorkerGlobalScope.caches