feat: send account switched messages to website

[rolznz]

Describe the changes you have made in this PR

Send a message to the website when user switches account.

To listen to the event the website would add an event listener like:

window.addEventListener(
  "message",
  (event) => {
      if (event.data === "accountSwitched") {
         //... do something here
      }
  },
);

Link this PR to an issue [optional]

Fixes #2503

Type of change

• feat: New feature (non-breaking change which adds functionality)

Screenshots of the changes [optional]

Add screenshots to make your changes easier to understand. You can also add a video here.

How has this been tested?

Manually

Checklist

• My code follows the style guidelines of this project and performed a self-review of my own code
• New and existing tests pass locally with my changes
• I checked if I need to make corresponding changes to the documentation (and made those changes if needed)
• Review security implications (we do not give any info about the account)
• Review the action name. Should it have some sort of prefix?
• How to document / promote this feature?

[github-actions]

🚀 Thanks for the pull request!

Here are the current build files for testing:

• chrome.zip.zip
• firefox.xpi.zip
• opera.crx.zip

Download and unzip the file for your browser. Refer to the readme for detailed install instructions.

Don't forget: keep earning sats!

[bumi]

best first also write a spec for window.nostr and window.webln

[MoritzKa]

Thanks for initiating this. With the possibility of having different Accounts in the extension, users have from time to time the wrong account selected without knowing it.
If we follow the NIP standardization process, we would need a working implementation first. But we should propose it maybe here and let people know? https://github.com/nostr-protocol/nips/blob/master/07.md
After that I can reach out to coracle, iris. I know the developers of Primal and snort but did not have direct contact yet.

[rolznz]

@MoritzKa I think the only way to successfully propose it is to create a PR. If we already have a working implementation then the PR may be reviewed more closely so maybe it is best to wait for that?

[rolznz]

I have assigned @pavanjoshi914 to help updating this PR to use the new .on() method for window.webln and window.nostr

[pavanjoshi914]

to handle events in the best way we can use EventEmitters node environments to provide such functionality. in our case, we can use an events package to handle events such as accountSelected.

here is the use case:

1. webln.on("accountSelected", callback) : let users subscribe to the event and add to the list of events
   

the package provides a complete set of methods required to handle events under EventEmitter class such as removing listener, emitting events, etc

other supported events: https://nodejs.org/dist/v11.13.0/docs/api/events.html#events_class_eventemitter

same eventEmitters are used by metaMask as well

[pavanjoshi914]

2023-07-20.19-59-41.mp4

website registering event

webln.on("accountSelected", callback);

website remove the event, insure to pass same function to remove listener successfully

webln.removeListener("accountSelected", callback)

[rolznz]

@pavanjoshi914 after this is merged and deployed, it would be great to do these follow up tasks:

• Create PR for updating NIP-07
• Update https://github.com/WebBTC/webln-types
• Update webln.guide with new .on and .off methods and the supported event types (only accountChanged for now)
• Possibly we can submit PRs to snort.social and other open source nostr clients to add this feature

[rolznz]

All this new code is duplicated in the two providers. I wonder if we can extend a common provider class or something. We could also move the common stuff like enabling and executing there.

I would do this as a follow up PR I guess.

[rolznz]

Looks good to me. I cannot approve it as I originally made the PR.

CC @bumi @reneaaron