# Handle Event Options

Currently this is not available in development, only in production or preview modes

When running in production or preview mode, Vitedge's handleEvent function accepts the following options.

# Request Lifecycle

Only available when deploying to Cloudflare Workers

Vitedge provides a set of lifecycle hooks that can be used to modify requests or add logs.

import { handleEvent } from 'vitedge/worker'

addEventListener('fetch', (event) => {
  try {
    event.respondWith(
      handleEvent(event, {
        willRequestApi({ url, query }) {
          console.log('API:', url.pathname, query)
        },
        didRequestRender({ response }) {
          if (response.status >= 300 && response.status < 400) {
            console.log('Page redirect:', response.headers.get('location'))
          }
        },
      })
    )
  } catch (error) {
    event.respondWith(
      new Response(error.message || error.toString(), {
        status: 500,
      })
    )
  }
})

This is the list of the available lifecycle hooks:

• willRequestAsset: Called before an asset is retrieved from KV. Receive { event } in the arguments.
• didRequestAsset: Called after an asset is retrieved from KV. Receive { event response } in the arguments. It can modify the response.
• willRequestApi: Called before an API handler runs. Receive { event, url, query } in the arguments.
• didRequestApi: Called after an API handler returns. Receive { event, url, query, response } in the arguments. It can modify the repsonse.
• willRequestProps: Called before a Page Props handler runs. Receive { event, url, query } in the arguments.
• didRequestProps: Called after a Page Props handler returns. Receive { event, url, query, response } in the arguments. It can modify the response.
• willRequestRender: Called before a page is rendered. Receive { event } in the arguments.
• didRequestRender: Called after a page is rendered. Receive { event response } in the arguments. It can modify the response.

# Skip SSR

The option skipSSR: boolean allows to skip the rendering for certain routes and simply return the naked index.html to fallback to a simple SPA. For example, the following would behave as an SPA for any route that includes /admin/.

handleEvent(event, {
  skipSSR: event.request.url.includes('/admin/')
})

# Global Cache Option

If you have same caching policy for different pages it is possible to define default cache configuration globally as follows.

handleEvent(event, {
  cache: { html:<number>, api: <number> }
})

Refer to caching section for moore details.

# HTTP2 Server Push

Thanks to HTTP/2 Server Push it is possible to push certain assets to the browser in parallel to the current request to avoid waterfall requests. The http2ServerPush: Array<'script' | 'style'> option allows selecting which assets are pushed.

handleEvent(event, {
  http2ServerPush: {
    destinations: ['style'],
  },
})

This will populate the Link header, which is then used by the browser to preload the assets.

Note: Behavior might differ depending on the browser.