Juit Capacitor Updater

This library demonstrates how to perform Capacitor live updates, which update the contents of the web application without requiring an update from the app store.

Please note that this is not intended to be production quality, but rather a simple showcase of the interaction between different Capacitor APIs that can be used to perform live updates.

• Outline
• Functions
  • updateCapacitor(...)
  • persistUpdates()
• License
• Copyright Notice

Outline

When Capacitor starts, it serves the web application bundled within the binary itself (the .ipa for iOS or .apk for Android).

The updateCapacitor(...) function performs the following steps:

1. Downloads a ZIP file from the specified URL.
2. Uses JSZip to extract the downloaded ZIP file in the Library directory of the app, following Capacitor's updates naming scheme.
3. Provides a callback to reload the current web view, pointing the root to the extracted ZIP file.

Upon restart, the persistUpdates() function can be called to persist the server base path (where the ZIP file was extracted) and use this for all subsequent uses of the app (e.g., when forcefully restarted).

Functions

This library exposes two functions:

updateCapacitor(...)

The updateCapacitor(...) async function downloads the specified URL, extracts it on the local device, and provides a callback to reload the web view with the updated content. It accepts the following arguments:

• url (required): A string or URL from which the ZIP file will be downloaded.
• progress (optional): A callback that will be invoked with a number between 0 and 1 indicating progress. Between 0.5, the progress indicates download; between 0.5 and 1, it indicates unzipping progress.
• verbose (optional): When true, the update process will be logged using console.log(...).

When successful, this function will asynchronously return a callback () => Promise<void> that needs to be invoked to reload the web view with the updated contents.

If the update could not be performed (either due to live-reload in Capacitor or when on the web) or in case of errors during downloading or unzipping, this function will throw an error asynchronously (returning a rejected promise).

persistUpdates()

Upon initialization of your app, always call persistUpdates() to ensure that app reloads will point to the latest updated code.

This function is safe to call anytime and on any platform, as it will only persist the path when the current server base path is indeed a directory created during an update with updateCapacitor(...).

This function is also asynchronous and will return a promise to a boolean indicating true when the path has been persisted.

This function will also prune the updates directory from all previous, unused updates, preserving only the current update.