CF File Cache Worker

worker.js

addEventListener('fetch', event => {
    event.respondWith(handleRequest(event))
})

async function handleRequest(event) {
    // try and find the file in cloudflare cache
    let request     = event.request
    let cache       = caches.default
    let response    = await cache.match(request)

    if (!response) {
        // File not found in Cache API so
        // Set the response to be the file from B2
        modRequest = new Request(request.url, {
            method: request.method
        })
        response = await fetch(modRequest)
        response = new Response(response.body, response)

        // Remove/Rename the BZHeaders
        try{
            if(response.headers.get('x-bz-content-sha1') === 'none'){
                response.headers.append('n-sha1', response.headers.get('x-bz-info-large_file_sha1'))
            }else {
                response.headers.append('n-sha1', response.headers.get('x-bz-content-sha1'))
            }
            response.headers.delete('x-bz-content-sha1')
            response.headers.delete('x-bz-info-large_file_sha1')
            response.headers.delete('x-bz-file-id')
            response.headers.delete('x-bz-file-name')
            response.headers.delete('x-bz-info-src_last_modified_millis')
            response.headers.delete('x-bz-upload-timestamp')
        }catch(ex){
            response.headers.append('n-cache-err', ex.message)
        }

        // If this file is less than 490MB then add it to the cache
        if (parseInt(response.headers.get('content-length')) < 513802240) {
            // response.headers.append('Transfer-Encoding', 'chunked')
            // response.headers.append('Cached-At', Date.now())
            // Cache this file
            event.waitUntil(cache.put(request, response.clone()))
        }else{
            response.headers.append('n-cache', 'file-over-500m')
        }
      
        // Set Cache Status
        response.headers.append('n-cache', 'miss')
      
    }else{
        response.headers.append('n-cache', 'hit')
    }
    return response
}