CacheStorage: match() method
Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
Note: This feature is available in Web Workers.
The match()
method of the CacheStorage
interface checks if a given Request
or URL string is a key for a stored Response
.
This method returns a Promise
for a Response
, or a Promise
which resolves to undefined
if no match is found.
You can access CacheStorage
through the Window.caches
property in windows or through the WorkerGlobalScope.caches
property in workers.
Cache
objects are searched in creation order.
Note: caches.match()
is a convenience method.
Equivalent functionality is to call cache.match()
on each cache (in the order returned by caches.keys()
) until a Response
is returned.
Syntax
match(request)
match(request, options)
Parameters
request
-
The
Request
you want to match. This can be aRequest
object or a URL string. options
Optional-
An object whose properties control how matching is done in the
match
operation. The available options are:ignoreSearch
-
A boolean value that specifies whether the matching process should ignore the query string in the URL. For example, if set to
true
, the?value=bar
part ofhttp://foo.com/?value=bar
would be ignored when performing a match. It defaults tofalse
. ignoreMethod
-
A boolean value that, when set to
true
, prevents matching operations from validating theRequest
http
method (normally onlyGET
andHEAD
are allowed.) It defaults tofalse
. ignoreVary
-
A boolean value that, when set to
true
, tells the matching operation not to performVARY
header matching. In other words, if the URL matches you will get a match regardless of whether theResponse
object has aVARY
header or not. It defaults tofalse
. cacheName
-
A string that represents a specific cache to search within.
Return value
Examples
This example is from the MDN simple service worker example (see simple service worker running live).
Here we wait for a FetchEvent
to fire. We construct a custom response
like so:
- Check whether a match for the request is found in the
CacheStorage
usingCacheStorage.match()
. If so, serve that. - If not, open the
v1
cache usingopen()
, put the default network request in the cache usingCache.put()
and return a clone of the default network request usingreturn response.clone()
. The last is necessary becauseput()
consumes the response body. - If this fails (e.g., because the network is down), return a fallback response.
self.addEventListener("fetch", (event) => {
event.respondWith(
caches.match(event.request).then((response) => {
// caches.match() always resolves
// but in case of success response will have value
if (response !== undefined) {
return response;
} else {
return fetch(event.request)
.then((response) => {
// response may be used only once
// we need to save clone to put one copy in cache
// and serve second one
let responseClone = response.clone();
caches.open("v1").then((cache) => {
cache.put(event.request, responseClone);
});
return response;
})
.catch(() => caches.match("/gallery/myLittleVader.jpg"));
}
}),
);
});
Specifications
Specification |
---|
Service Workers # cache-storage-match |
Browser compatibility
BCD tables only load in the browser