On Tue, Jun 9, 2015 at 10:19 AM, Andrew Grieve <[email protected]> wrote:
> I think the only place sticky channels are used is for startup events > (deviceready, nativeready, pluginsready, etc). I think you could probably > change them to fire multiple times without breaking too much, but the > semantics of that seem really strange to me (fire the most recent event, or > all events? upon registering, but only to the newly added listener(s)) > > They are not based on any standard, so it might be nice not to use them, > and instead use standard events (e.g. cordova.fireWindowEvent). As long as > we promise not to fire them until after deviceready, apps should be able to > register listeners reliably. > This was an area that I was hoping to leverage to use promises instead, back when we were discussing baking those into cordova.js -- it would be a major change from the existing way of doing things, but sticky channels are closer in spirit to promises than they are to events, I think. It's very similar to the service worker `ready` attribute -- before the worker is active, it returns a promise that asynchronously waits for everything to be ready, and then fires. After the worker is already active, the promise resolves immediately, just like deviceready does if you attach a listener after Cordova has initialized. > > One other data point for this is that I dealt with the as-a-service vs. > as-a-launch in > https://github.com/MobileChromeApps/cordova-plugin-background-app. In this > model, I set a property before each resume / deviceready that can be > queried to find out the app's state. Could possibly do similar for intents > (but would need an event as well since they can come at any time, not just > on start-up) > > On Fri, Jun 5, 2015 at 7:18 PM, Jesse <[email protected]> wrote: > > > I have been looking into unifying launchParameters across devices so that > > all cordova apps can get some context of how they were > launched/activated. > > This includes everything from a url/protocol launch in another app, to a > > touch on a notification (toast,local,push,... ) > > > > My intent was to add a channel for this, however I have had some issues > > with channels + stickiness. > > > > I wanted a channel that would call new subscribers immediately if it had > > already fired. In our channel implementation this is what we call a > sticky > > channel. However, this particular channel may fire more than once, ie. > we > > could be activated multiple times while running, or receive multiple > > notifications. > > The current implementation for sticky will only ever call subscribers > once, > > and if I call fire() more than once, it actually removes it's > subscribers. > > [1] So I cannot use this as is for my needs. > > > > So my questions are : > > 1. Why is like this? Is there some standard or expectation that this is > > based on? > > 2. Can I change it? What would be the impact of changing the behavior to > > have a sticky channel fire more than once, and keep its list of > > subscribers? > > 3. Are there historical reasons that things are the way they are? The > code > > has been through several major moves since it was written, so it is > > difficult to pin the original commit (Fil, Andrew? some merged pr?) If > > there are historical reasons, are they still relevant? > > > > Please keep in mind too that I am not asking for the solution to my > > specific task, I can work around anything ... I am asking solely about > the > > current channel-sticky implementation and it we should change it. > > > > Cheers, > > Jesse > > > > > > The current implementation > > [1] > > > https://github.com/apache/cordova-js/blob/master/src/common/channel.js#L216 > > > > > > @purplecabbage > > risingj.com > > >
