[🚀 Feature]: Ability to unsubscribe from CDP events

[boris-petrov]

Feature and motivation

Right now we can subscribe for events which is awesome!

devtools = Capybara.current_session.driver.browser.devtools
devtools.network.enable
devtools.network.on(:web_socket_frame_sent) { |params| puts params }

However, it's not possible to unsubscribe from these events (something like an off method).

Usage example

Perhaps an off method similar to on:

devtools = Capybara.current_session.driver.browser.devtools
devtools.network.enable
callback = lambda { |params| puts params }
devtools.network.on(:web_socket_frame_sent, lambda)
devtools.network.off(:web_socket_frame_sent, lambda)

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Thank you!

[titusfortner]

@pujagani does Java support unsubscribing from events, yet?

[boris-petrov]

@titusfortner sorry, I should have mentioned - in my case the language is Ruby. I don't know if the rest of the languages have support for unsubscription.

[titusfortner]

@boris-petrov yes I know, but Puja has been the one working the most on our upcoming BiDi implementations in Java and I'm curious how (if) Java is handling this. We may not add support for it in Ruby to Chrome DevTools, but I do think we need to be able to support it for the WebDriver BiDi spec implementation.

[pujagani]

This is where the closeable part comes in from the Java end. Where we unsubscribe from the events of the module when close() gets called. Also, if the user has access to the BiDi object (which handles the underlying command sending etc), there is an unsubscribe method which internally calls the W3C BiDi unsubscribe method https://w3c.github.io/webdriver-bidi/#command-session-unsubscribe.

[joerg1985]

I think it would be nice to unsubscribe from single events. The BiDi has a public <X> void clearListener(Event<X> event) { which is missing for the DevTools. So are there any reasons not to add this method to the DevTools too?

Another option would be to return a Closable when calling DevTools.addListener to detach the listener, when Closable.close is called. This would allow to remove the added listener instead of all for a specific event.

What option would you prefere?

[pujagani]

I think for Java, we can do something similar to what BiDi already has. But it depends on what the user is looking for.

[titusfortner]

@p0deje how hard would it be to implement this in Ruby? I'm more interested in our BiDi implementation than CDP, obviously.

[p0deje]

@titusfortner It should be fairly straightforward, we just need to clear @devtools.callbacks properly which is simply a hash of event => listeners. I'm not sure what the API should look like for this. Which looks more reasonable?

Option 1

listener = devtools.network.on(:web_socket_frame_sent) { |params| puts params }
listener.close

Option 2

callback = ->(params) { puts params }
devtools.network.on(:web_socket_frame_sent, &callback)
devtools.network.off(:web_socket_frame_sent, &callback)

Option 3

callback = ->(params) { puts params }
devtools.network.on(:web_socket_frame_sent, &callback)
devtools.network.events[:web_socket_frame_sent].delete(callback)
devtools.network.events[:web_socket_frame_sent].clear # remove all

[github-actions[bot]]

This issue is stale because it has been open 280 days with no activity. Remove stale label or comment or this will be closed in 14 days.

[github-actions[bot]]

This issue was closed because it has been stalled for 14 days with no activity.

[github-actions[bot]]

This issue has been automatically locked since there has not been any recent activity since it was closed. Please open a new issue for related bugs.