CacheStorage

The CacheStorage interface represents the storage for Cache objects.

The interface:

Use CacheStorage.open() to obtain a Cache instance.

Use CacheStorage.match() to check if a given Request is a key in any of the Cache objects that the CacheStorage object tracks.

You can access CacheStorage through the global caches property.

Note: CacheStorage always rejects with a 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.
Note: CacheStorage.match() is a convenience method. Equivalent functionality to match a cache entry can be implemented by returning an array of cache names from CacheStorage.keys(), opening each cache with CacheStorage.open(), and matching the one you want with Cache.match().

Methods

CacheStorage.match()
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 that match.
CacheStorage.has()
Returns a Promise that resolves to true if a Cache object matching the cacheName exists.
CacheStorage.open()
Returns a Promise that resolves to the Cache object matching the cacheName (a new cache is created if it doesn't already exist.)
CacheStorage.delete()
Finds the Cache object matching the cacheName, and if found, deletes the Cache object and returns a Promise that resolves to true. If no Cache object is found, it returns false.
CacheStorage.keys()
Returns a Promise that will resolve with an array containing strings corresponding to all of the named Cache objects tracked by the CacheStorage. Use this method to iterate over a list of all the 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 InstallEvent to fire, then runs waitUntil to handle the install process for the app. This consists of calling CacheStorage.open to create a new cache, then using Cache.addAll to add a series of assets to it.

In the second code block, 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. If so, serve that.
  2. 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 Cache.put (cache.put(event.request, response.clone()).)
  3. 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 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/bountyHunters.jpg',
        '/sw-test/gallery/myLittleVader.jpg',
        '/sw-test/gallery/snowTroopers.jpg'
      ]);
    })
  );
});

this.addEventListener('fetch', function(event) {
  var response;
  event.respondWith(caches.match(event.request).catch(function() {
    return fetch(event.request);
  }).then(function(r) {
    response = r;
    caches.open('v1').then(function(cache) {
      cache.put(event.request, response);
    });
    return response.clone();
  }).catch(function() {
    return caches.match('/sw-test/gallery/myLittleVader.jpg');
  }));
});

This snippet shows how the API can be used outside of a service worker context, and uses the `await` operator for much more readable code.

// Try to get data from the cache, but fall back to fetching it live.
async function getData() {
   const cacheVersion = 1;
   const cacheName    = `myapp-${ cacheVersion }`;
   const url          = 'https://jsonplaceholder.typicode.com/todos/1';
   let cachedData     = await getCachedData( cacheName, url );

   if ( cachedData ) {
      console.log( 'Retrieved cached data' );
      return cachedData;
   }

   console.log( 'Fetching fresh data' );

   const cacheStorage = await caches.open( cacheName );
   await cacheStorage.add( url );
   cachedData = await getCachedData( cacheName, url );
   await deleteOldCaches( cacheName );

   return cachedData;
}

// Get data from the cache.
async function getCachedData( cacheName, url ) {
   const cacheStorage   = await caches.open( cacheName );
   const cachedResponse = await cacheStorage.match( url );

   if ( ! cachedResponse || ! cachedResponse.ok ) {
      return false;
   }

   return await cachedResponse.json();
}

// Delete any old caches to respect user's disk space.
async function deleteOldCaches( currentCache ) {
   const keys = await caches.keys();

   for ( const key of keys ) {
      const isOurCache = 'myapp-' === key.substr( 0, 6 );

      if ( currentCache === key || ! isOurCache ) {
         continue;
      }

      caches.delete( key );
   }
}

try {
   const data = await getData();
   console.log( { data } );
} catch ( error ) {
   console.error( { error } );
}

Specifications

Specification Status Comment
Service Workers
The definition of 'CacheStorage' in that specification.
Working Draft Initial definition.

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
CacheStorage
Experimental
Chrome Full support 40
Notes
Full support 40
Notes
Notes Accessible from Window from version 43.
Notes Accessible from WorkerGlobalScope from version 43.
Edge Full support YesFirefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR.)
IE No support NoOpera Full support 27Safari Full support 11.1WebView Android Full support 40
Notes
Full support 40
Notes
Notes Accessible from Window from version 43.
Notes Accessible from WorkerGlobalScope from version 43.
Chrome Android Full support 40
Notes
Full support 40
Notes
Notes Accessible from Window from version 43.
Notes Accessible from WorkerGlobalScope from version 43.
Firefox Android Full support 44Opera Android Full support 27Safari iOS Full support YesSamsung Internet Android ?
delete
Experimental
Chrome Full support 40Edge Full support 16Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR.)
IE No support NoOpera Full support 27Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 27Safari iOS Full support YesSamsung Internet Android ?
has
Experimental
Chrome Full support 40Edge Full support 16Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR.)
IE No support NoOpera Full support 27Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 27Safari iOS Full support YesSamsung Internet Android ?
keys
Experimental
Chrome Full support 40Edge Full support 16Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR.)
IE No support NoOpera Full support 27Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 27Safari iOS Full support YesSamsung Internet Android ?
match
Experimental
Chrome Full support 54
Full support 54
Partial support 40
Notes
Notes The options parameter only supports ignoreSearch, and cacheName.
Edge Full support 16Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR.)
IE No support NoOpera Full support 41
Full support 41
Partial support 27
Notes
Notes The options parameter only supports ignoreSearch, and cacheName.
Safari Full support 11.1WebView Android Full support 54
Full support 54
Partial support 40
Notes
Notes The options parameter only supports ignoreSearch, and cacheName.
Chrome Android Full support 54
Full support 54
Partial support 40
Notes
Notes The options parameter only supports ignoreSearch, and cacheName.
Firefox Android Full support 44Opera Android Full support 41
Full support 41
Partial support 27
Notes
Notes The options parameter only supports ignoreSearch, and cacheName.
Safari iOS Full support YesSamsung Internet Android ?
open
Experimental
Chrome Full support 40Edge Full support 16Firefox Full support 44
Notes
Full support 44
Notes
Notes Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR.)
IE No support NoOpera Full support 27Safari Full support 11.1WebView Android Full support 40Chrome Android Full support 40Firefox Android Full support 44Opera Android Full support 27Safari iOS Full support YesSamsung Internet Android ?

Legend

Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
See implementation notes.
See implementation notes.

See also