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, FetchEvent.respondWith(any value)
returns a promise back to the controlled page. 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 Workers The definition of 'FetchEvent' in that specification. |
Working Draft | Initial definition. |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
request | Chrome Full support Yes | Edge ? | 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.