Cancel request before it is sent

Is it possible to cancel an action before the corresponding HTTP request is sent?

From the readme, here’s what we have to work with before a message is sent.

gmail.observe.before('send_message', function(url, body, data, xhr){ }

I was thinking it might be possible to cancel the xhr request, but it hasn’t even been sent yet.

The use case it to perform a check and prompt the user for confirmation if certain conditions are met.

[Nateowami]

Thanks for the suggestions. I considered hooking into the click event, but I didn’t know how to get the list of email addresses from the To, CC, and BCC fields. Looking at the API a bit more though, I now see there’s a recipient_change event that does just that.

I’m a bit confused about the documentation though:

gmail.observe.on('recipient_change', function(match, recipients) {
  console.log('recipients changed', match, recipients);
});

I’m not sure what “match” refers to. From experimenting in the console it appears to be a large DOM element holding everything but the header in the compose dialog. I’m guessing this is in order to find this element in the DOM tree in order to track down which compose dialog it came from?

Actually, with this event handler, maybe I don’t even need to intercept a click–just change some styling or something as a warning.

Anyway, thanks so much for the help! Much appreciated. 😄

[Nateowami]

Thanks. I may investigate that route. I also just discovered the abort() method on the xhr object. Just experimenting in the console it appeared aborting it before it was sent would keep it from being sent at all (as long as it was open()ed before being abort()ed). It’s looking promising