Improve performance

[jhnns]

I'm using review for developing an interactive widget. The widget is designed to run on different screen sizes and different types of data (variable amount of columns). That's why I need to keep an eye on ~15 states.

review is a good support for this task, but unfortunately it takes quite some time to reload 15 screenshots. After digging into the source code I saw that review spawns a child_process for every image. This adds ~2 seconds delay on every image.

I thought about ways how multiple screenshots could be rendered more efficiently:

• Maybe there is the possibility to keep the process running. Thus we just need to tell the process to reload a given site.
• We could also render different resolutions by just resizing the viewport. This of course should only be optional as it might not be intended. Additionally there should be a delay because maybe there are some scripts that need to be executed on resize.

What do you think?

[juliangruber]

When I last tried long running phantomjs processes they crashed too often on me, might not be an issue any more though. Then we could spawn n procs and have a work queue for new screenshots.

I'm down with trying that but don't have the time right now.

[jhnns]

I could give it a try though I'm not too experienced with sub processes and work queues. How would you communicate between the processes? As far as I know there is no stdin available in phantomjs.

But we could spin up a webserver and communicate via localhost. I think that's exactly what phantomjs-wrapper does.

What do you think, should I give it a try using phantomjs-wrapper and open a pull-request?

[jhnns]

And what do you think about just resizing the page? I think this is the way you'd usually test your webpages manually. Why shouldn't review speed up the rendering process by doing it exactly the same way? As I mentioned, it should be opt-out if reloading the page is necessary (but I'd turn it on by default).

[juliangruber]

Yeah I think http should be the way to go. And for resizing, SGTM :)