Cache.put()

This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

The put() method of the Cache interface allows key/value pairs to be added to the current Cache object.

Often, you will just want to fetch() one or more requests, then add the result straight to your cache. In such cases you are better off just using Cache.add/Cache.addAll, as they are shorthand functions for one or more of these operations:

fetch(url).then(function (response) {
  if (!response.ok) {
    throw new TypeError('bad response status');
  }
  return cache.put(url, response);
})

Note: put() will overwrite any key/value pair previously stored in the cache that matches the request.

Note: Cache.add/Cache.addAll do not cache responses with Response.status values that are not in the 200 range, whereas Cache.put lets you store any request/response pair. As a result, Cache.add/Cache.addAll can't be used to store opaque responses, whereas Cache.put can.

Note: Initial Cache implementations (in both Blink and Gecko) resolve Cache.add, Cache.addAll, and Cache.put promises when the response body is fully written to the disk.  More recent spec versions have newer language stating that the browser can resolve the promise as soon as the entry is recorded in the database even if the response body is still streaming in.

Syntax

cache.put(request, response).then(function() {
  // request/response pair has been added to the cache
});

Returns

A promise that resolves with void.

Note: The promise will reject with a TypeError if the URL scheme is not http or https.

Parameters

request
The Request you want to add to the cache.
response
The Response you want to match up to the request.

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.
var response;
var cachedResponse = 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');
});

Specifications

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

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 40.0 39 (39)[1] No support 24 No support
Require HTTPS 46.0 (Yes)[1] ? ? ?
Feature Android Android Webview Firefox Mobile (Gecko) Firefox OS IE Mobile Opera Mobile Safari Mobile Chrome for Android
Basic support No support No support 39.0 (39) ? No support ? No support 40.0
Require HTTPS No support No support (Yes) ? ? ? ? 46.0

[1] Service workers (and Push) have been disabled in the Firefox 45 & 52 Extended Support Releases (ESR.)

See also

Document Tags and Contributors

 Last updated by: chrisdavidmills,