{{APIRef("Service Workers API")}}{{SeeCompatTable}}
The CacheStorage
interface represents the storage for {{domxref("Cache")}} objects. It provides a master directory of all the named caches that a {{domxref("ServiceWorker")}}, other type of worker or {{domxref("window")}} scope can access (you don't have to use it with service workers, even thought that is the spec that defines it) and maintains a mapping of string names to corresponding {{domxref("Cache")}} objects.
CacheStorage
also exposes {{domxref("CacheStorage.open()")}} and {{domxref("CacheStorage.match()")}}. Use {{domxref("CacheStorage.open()")}} to obtain a {{domxref("Cache")}} instance. Use {{domxref("CacheStorage.match()")}} to check if a given {{domxref("Request")}} is a key in any of the {{domxref("Cache")}} objects that the CacheStorage
object tracks.
You can access CacheStorage
through the global {{domxref("WorkerGlobalScope.caches", "caches")}} property.
SecurityError
on untrusted origins (i.e. those that aren't using HTTPS, although this definition will likely become more complex in the future.) When testing you can get around this by checking the "Enable Service Workers over HTTP (when toolbox is open)" option in the Firefox Devtools options/gear menu.Methods
- {{domxref("CacheStorage.match()")}}
- Checks if a given {{domxref("Request")}} is a key in any of the {{domxref("Cache")}} objects that the {{domxref("CacheStorage")}} object tracks and returns a {{jsxref("Promise")}} that resolves to that match.
- {{domxref("CacheStorage.has()")}}
- Returns a {{jsxref("Promise")}} that resolves to
true
if a {{domxref("Cache")}} object matching thecacheName
exists. - {{domxref("CacheStorage.open()")}}
- Returns a {{jsxref("Promise")}} that resolves to the {{domxref("Cache")}} object matching the
cacheName
(a new cache is created if it doesn't exist.) - {{domxref("CacheStorage.delete()")}}
- Finds the {{domxref("Cache")}} object matching the
cacheName
, and if found, deletes the {{domxref("Cache")}} object and returns a {{jsxref("Promise")}} that resolves totrue
. If no {{domxref("Cache")}} object is found, it returnsfalse
. - {{domxref("CacheStorage.keys()")}}
- Returns a {{jsxref("Promise")}} that will resolve with an array containing strings corresponding to all of the named {{domxref("Cache")}} objects tracked by the {{domxref("CacheStorage")}}. Use this method to iterate over a list of all the {{domxref("Cache")}} objects.
Examples
This code snippet is from the MDN sw-test example (see sw-test running live.) This service worker script waits for an {{domxref("InstallEvent")}} to fire, then runs {{domxref("ExtendableEvent.waitUntil","waitUntil")}} to handle the install process for the app. This consists of calling {{domxref("CacheStorage.open")}} to create a new cache, then using {{domxref("Cache.addAll")}} to add a series of assets to it.
In the second code block, we wait for a {{domxref("FetchEvent")}} to fire. We construct a custom response like so:
- Check whether a match for the request is found in the CacheStorage. If so, serve that.
- If not, fetch the request from the network, then also open the cache created in the first block and add a clone of the request to it using {{domxref("Cache.put")}} (
cache.put(event.request, response.clone())
.) - If this fails (e.g. because the network is down), return a fallback response.
Finally, return whatever the custom response ended up being equal to, using {{domxref("FetchEvent.respondWith")}}.
this.addEventListener('install', function(event) { event.waitUntil( caches.open('v1').then(function(cache) { return cache.addAll([ '/sw-test/', '/sw-test/index.html', '/sw-test/style.css', '/sw-test/app.js', '/sw-test/image-list.js', '/sw-test/star-wars-logo.jpg', '/sw-test/gallery/', '/sw-test/gallery/bountyHunters.jpg', '/sw-test/gallery/myLittleVader.jpg', '/sw-test/gallery/snowTroopers.jpg' ]); }) ); }); this.addEventListener('fetch', function(event) { var cachedResponse = caches.match(event.request).catch(function() { return fetch(event.request).then(function(response) { return caches.open('v1').then(function(cache) { cache.put(event.request, response.clone()); return response; }); }); }).catch(function() { return caches.match('/sw-test/gallery/myLittleVader.jpg'); }); event.respondWith(cachedResponse); });
Specifications
Specification | Status | Comment |
---|---|---|
{{SpecName('Service Workers', '#cache-storage', 'CacheStorage')}} | {{Spec2('Service Workers')}} | Initial definition. |
Browser compatibility
{{CompatibilityTable}}
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|
Basic support | {{CompatChrome(40.0)}} | {{CompatGeckoDesktop(44)}}[1] | {{CompatNo}} | {{CompatUnknown}} | {{CompatNo}} |
Accessible from {{domxref("Window")}} | {{CompatChrome(43.0)}} | {{CompatGeckoDesktop(44)}}[1] | {{CompatUnknown}} | {{CompatUnknown}} | {{CompatUnknown}} |
Accessible from {{domxref("WorkerGlobalScope")}} | {{CompatChrome(43.0)}} | {{CompatGeckoDesktop(44)}}[1] | {{CompatUnknown}} | {{CompatUnknown}} | {{CompatUnknown}} |
Feature | Android | Android Webview | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile | Chrome for Android |
---|---|---|---|---|---|---|---|
Basic support | {{CompatNo}} | {{CompatNo}} | {{CompatGeckoMobile(44)}} | {{CompatVersionUnknown}} | {{CompatVersionUnknown}} | {{CompatVersionUnknown}} | {{CompatChrome(40.0)}} |
Accessible from {{domxref("Window")}} | {{CompatNo}} | {{CompatNo}} | {{CompatGeckoMobile(44)}} | {{CompatUnknown}} | {{CompatUnknown}} | {{CompatUnknown}} | {{CompatChrome(43.0)}} |
Accessible from {{domxref("WorkerGlobalScope")}} | {{CompatNo}} | {{CompatNo}} | {{CompatGeckoMobile(44)}} | {{CompatUnknown}} | {{CompatUnknown}} | {{CompatUnknown}} | {{CompatChrome(43.0)}} |
[1] Service workers (and Push) have been disabled in the Firefox 45 Extended Support Release (ESR.)
See also
- Using Service Workers
- {{domxref("Cache")}}
- {{domxref("WorkerGlobalScope.caches")}}