Making the self-hosted Capacitor web server proxy site if online, serve saved files otherwise

[sj-dixon]

Hello Capacitor Community,

I am looking for feedback on my plan to implement an app that caches the last known version of a website for offline access.

My organization is looking to turn progressive web application into an offline-first mobile using Capacitor. Some users will continue to use the web application through the desktop, but other users will be using it on their devices while in remote areas until they come back for a new version. One of the capabilities we'd like to have is the ability to serve over-the-air updates, and then cache the files for offline use.

Here is an example workflow:

• Day 1: User A downloads app (version 1) from the app store, in the city. The user then drives to a wilderness area and stays there for 14 days before coming back to the city.
• Day 3: My organization updates the main website (version 2).
• Day 5: user A realizes he needs a critical bugfix, so he puts the device on a helicopter by itself. The helicopter arrives in the city. User B receives the device, launches the app while on WiFi, and it now runs version 2. They put the device back on the helicopter and it goes back to user A.

We don't want to have to publish the app through the app store every time we want to make an update like this.

For Android, my plan is to:

• fork the Capacitor repository
• introduce a factory class to swap WebViewLocalServer for a server class of my own creation
• write a new server class that if offline, uses static assets in a 'downloads' folder; otherwise, it will proxy the main website
• it'll overwrite the Documents folder on app startup if the remote version.json != the local version.json
• the offline cache will be pulled down as a zip whose contents are equivalent to the main website.

For iOS, I plan to find the equivalent of these same steps and then implement it more or less the same way.

Questions:

1. does this plan seem viable?
2. is there a better way of approaching this problem, without having to fork the repository?
3. does this implementation align with any roadmap item currently implemented or planned?
4. is there interest in this feature in the main Capacitor project?

[sj-dixon]

On further investigation I learned about the AppFlow product, https://ionicframework.com/docs/appflow/deploy/intro, which I suppose would be a pretty good alternative to doing it myself since it seems to cover all the same bases.