The request
read-only property of the FetchEvent
interface returns the Request
that triggered the event handler.
This property is non-nullable (since version 46, in the case of Firefox.) If a request is not provided by some other means, the constructor init
object must contain a request (see FetchEvent.FetchEvent()
.)
Syntax
var recentRequest = fetchEvent.request;
Value
A Request
object.
Example
This code snippet is from the service worker fetch sample (run the fetch sample live). The ServiceWorkerGlobalScope.onfetch
event handler listens for the fetch
event. When fired, pass a promise that back to the controlled page to FetchEvent.respondWith()
. This promise resolves to the first matching URL request in the Cache
object. If no match is found, the code fetches a response from the network.
The code also handles exceptions thrown from the ServiceWorkerGlobalScope.fetch
operation. Note that an HTTP error response (e.g., 404) will not trigger an exception. It will return a normal response object that has the appropriate error code set.
self.addEventListener('fetch', function(event) {
console.log('Handling fetch event for', event.request.url);
event.respondWith(
caches.match(event.request).then(function(response) {
if (response) {
console.log('Found response in cache:', response);
return response;
}
console.log('No response found in cache. About to fetch from network...');
return fetch(event.request).then(function(response) {
console.log('Response from network is:', response);
return response;
}).catch(function(error) {
console.error('Fetching failed:', error);
throw error;
});
})
);
});
Specifications
Specification | Status | Comment |
Service WorkersThe definition of 'request' in that specification. | Working Draft | Initial definition. |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Update compatibility data on GitHub
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Chrome
Full support Yes |
Edge
Full support ≤79 |
Firefox
Full support 44 |
IE
No support No |
Opera
Full support Yes |
Safari
No support No |
WebView Android
Full support Yes |
Chrome Android
Full support Yes |
Firefox Android
? |
Opera Android
Full support Yes |
Safari iOS
No support No |
Samsung Internet Android
Full support Yes |
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 also
- Using Service Workers
- Service workers basic code example
- Is ServiceWorker ready?
Promise
- Using web workers
FetchEvent.request by Mozilla Contributors is licensed under CC-BY-SA 2.5.