One of the authors of FastBoot here. I'm happy to answer any questions anyone has.
(P.S. One thing I think that's pretty meta-cool about the FastBoot site is that it is, itself, a FastBoot site, running on Heroku.)
(P.S. One thing I think that's pretty meta-cool about the FastBoot site is that it is, itself, a FastBoot site, running on Heroku.)
Everything is working just like you would set it up with React, except that with Ember declaring data dependencies on route is existing convention. And React gives you maybe a little bit more control around that.
That makes sense, I believe that's exactly what react-async does (if I recall correctly?) with react-router.
For our project, we basically call "await ApiActions.getData(routeParams)" in the server's route, after pulling that params out, which is effectively the same idea, and it worked quite well. I'm curious how one would tackle that from a different perspective, but it seems we all end up coming to the same conclusion!
Normally Ember app would render everything within the browser after all JS is downloaded and components etc. are processed. With Fastboot, somehow an additional, non-interfering layer of computation on the server does the same loop (without having to download anything and without significantly slowing down overall client app JS initialization) and sends the output to the client. It does it for every route separately. I'm guessing that somehow the client's processing is disabled on that first "pageview" to avoid double calculation. Is that correct? (if it is, it's very cool :)
With Fastboot, somehow an additional, non-interfering layer of computation on the server does the same loop (without having to download anything and without significantly slowing down overall client app JS initialization)
First the browser downloads the HTML, then the JavaScript, then the JavaScript runs and fetches the data via XHR. Only then does the user see the content they were after in the first place.
This actually works surprisingly well for "workspace" apps where the user is using it throughout the day (Gmail, Google Docs, etc.) On modern devices with good broadband, the difference is negligible.
But the thing this sucks for is content sites, where you aren't using an "app" but you're just clicking a link in Twitter or something. If it doesn't load within a second or so, you aren't that invested that you don't just close the tab. That has been the biggest source of pushback on frameworks like Angular and Ember for sites like this.
FastBoot bends the curve by replacing that static HTML file. Rather than serving an empty document that just points to JavaScript assets, we keep your Ember app running in Node.js on the server. When an HTTP request comes in, we direct it to Ember's router, where it figures out what models to load and components to render. When it finishes, it sends the document back to the browser.
You can think about this is as effectively outsourcing the JavaScript runtime to the server for the first load, but then the browser can take over again on subsequent navigations so it's very fast.
I think FastBoot is a great option for search crawlers, Facebook and Twitter embedding (it supports Open Graph and Twitter Cards), and supporting JavaScript-less clients. Most importantly, it's a way to get content quickly to users with a cold cache.
That said, we are planning to aggressively take advantage of App Cache and Service Worker, so ideally any second-time visitor to your site only has to fetch the raw data to see what they're after.
I'm guessing that somehow the client's processing is disabled on that first "pageview" to avoid double calculation. Is that correct? (if it is, it's very cool :)
Specifically, ember-engines provides a way to separate code into logical apps, but having them appear to be a single app. It's currently 'experimental', but in very active development.
https://github.com/dgeb/ember-engines
For us, it provides the best-of-both worlds... a single interface to the customer, without having to load up all of the code, services, etc that are used in every corner of the app.
Aren't we now just back to square one again in terms of MVC frameworks? What are the advantages here over simply implementing Django, RoR, Spring, Laravel, etc and cutting back on the JS (at least in terms of content-driven sites)?
You get all of the advantages of single page apps, without the unresponsive initial load time. There are also whole classes of apps you can't build with Django, RoR etc, so the question is a bit ridiculous IMO.
Wait, is one use-case that works out of the box to have a view that works both in text-mode browsers, like w3m and lynx (or graphical browsers with js disabled due to security or other reasons), and also "ramps up" to work well as "regular" SPAs?
Because that's one thing I've yet to see anyone really pull off: being able to define sane, simple components/widgets that also works reasonably without javascript (eg: the ability to render data as a table, and have click-able headings for sort that works both in lynx and without hitting the server in a modern js browser).
[ed: It certainly appears that http://www.ember-fastboot.com/docs/user-guide works well enough with js off, except for a couple of images not rendering.]
Btw great job!
That said, it should work just fine once the Ember app finishes loading and running in the browser. I would love it if you could file an issue on the Ember Inspector GitHub page with the error you're getting.
What is this? And why should I use it? I slummed through the quick start but that didn't make me any wiser.
EDIT: I read up on your blog post and you guys should definitely put some of that into the web page.
In addition, Glimmer 2 is near completion, and when ready will provide further speed ups to initial rendering.