« Kevin Ngo

Cache Manifest 'Download Failed' on Firefox Marketplace

20 Jan 2014

If you are developing a FirefoxOS app but running into a Download Failed error when others try to install your app on the Firefox Marketplace, it may be due to a problem with your cache manifest if you have implemented offline caching.

This issue, which I have run into before, can be due to the device not being able to download an asset listed on the cache manifest, resulting in a failed installation. To fix this, go through every item in the cache manifest and make sure that:

• the paths are correct
• the files exist
• the files are reachable

It should work once these issues are resolved. When releasing an update for an app, make sure that any deleted files are removed from the manifest and that newly added files have the correct path. There is currently a bug ticket open for the Firefox Marketplace about caching these errors upon app submission.

PS: a useful tool I sometimes use when I work with cache manifests is this AppCache generator.