Chrome doesn't use cache after power loss? - google-chrome

Question

I am creating a digital signage player that uses Chrome as it's display engine. We need to be able to still muddle along if the network goes down without too much interruption.
Chrome works fine caching images, and I've set the "Exipres" header to be a month after access. I can set the player computer offline and have the app run for days with no problem. If I reboot the machine the right way (Start->Shut Down), caching still works as expected.
The issue is that when Chrome exits abnormally - Either a crash or power loss - on reboot, Chrome ignores the cache and refuses to load images. This happens if I cut power 5 minutes after it loads the page, so content is not expiring.
My guess is that Chrome is set to ignore the cache after an abnormal exit to prevent corrupted cache from continually crashing the browser. However, this behavior is not what I need.
Does anyone know of a command line arg or flag I can set to keep this from happening?
Thanks for your help.

Answer 1

I tried everything I could think of to make Chrome not invalidate the local cache on system failure, and came up empty. There's a few other people who had the same question, and I didn't see an answer.
Here's what I did that made this work, and if someone else is having the same problem, it might be the workaround that you need.
I added a service worker that would cache images. The code below isn't perfect yet, but should be a starting place for someone... (FYI, I learned this 5 minutes ago, so if someone wants to give me a pointer or two on how to make this more elegant, I'm all ears.)
We cache anything that has a response type of "cors" so we cache only images coming from the remote server. Note that your images must be loaded via https for this to work.
Taken (mostly) from: https://developers.google.com/web/fundamentals/getting-started/primers/service-workers
var CACHE_NAME = 'shine_cache';
var urlsToCache = [
'/'
];
self.addEventListener('install', function(event) {
// Perform install steps
event.waitUntil(
caches.open(CACHE_NAME)
.then(function(cache) {
console.log('Opened cache');
return cache.addAll(urlsToCache);
})
);
});
self.addEventListener('fetch', function(event) {
//console.log('Handling fetch event for', event.request);
if (event.request.method == 'POST') {
//console.log("Skipping POST");
event.respondWith(fetch(event.request));
return;
}
if (event.request.headers.get('Accept').indexOf('image') !== -1) {
event.respondWith(
caches.match(event.request)
.then(function(response) {
// Cache hit - return response
if (response) {
console.log("Returning from cache.", event.request);
return response;
}
// IMPORTANT: Clone the request. A request is a stream and
// can only be consumed once. Since we are consuming this
// once by cache and once by the browser for fetch, we need
// to clone the response.
var fetchRequest = event.request.clone();
return fetch(fetchRequest).then(
function(response) {
console.log("Have a response.", response);
// Check if we received a valid response
if(!response || response.status !== 200 || response.type !== 'cors') {
return response;
}
// IMPORTANT: Clone the response. A response is a stream
// and because we want the browser to consume the response
// as well as the cache consuming the response, we need
// to clone it so we have two streams.
var responseToCache = response.clone();
caches.open(CACHE_NAME)
.then(function(cache) {
console.log("Caching response", event.request);
cache.put(event.request, responseToCache);
});
return response;
}
);
})
);
}
});