An Ember CLI addon that allows you to render and serve Ember.js apps on the server. Using FastBoot, you can serve rendered HTML to browsers and other clients without requiring them to download JavaScript assets.
Currently, the set of Ember applications supported is extremely limited. As we fix more issues, we expect that set to grow rapidly. See Known Limitations below for a full-list.
The bottom line is that you should not (yet) expect to install this add-on in your production app and have FastBoot work.
FastBoot requires Ember 2.3 or higher.
From within your Ember CLI application, run the following command:
ember install ember-cli-fastboot
ember fastboot --serve-assets- Visit your app at
http://localhost:3000.
You may be shocked to learn that minified code runs faster in Node than non-minified code, so you will probably want to run the production environment build for anything "serious."
ember fastboot --environment production
You can also specify the port (default is 3000):
ember fastboot --port 8088
See ember help fastboot for more.
When your app is running in FastBoot, it may need to use Node packages to replace features that are available only in the browser.
For security reasons, your Ember app running in FastBoot can only access packages that you have explicitly whitelisted.
To allow your app to require a package, add it to the
fastbootDependencies array in your app's package.json:
{
"name": "my-sweet-app",
"version": "0.4.2",
"devDependencies": {
// ...
},
"dependencies": {
// ...
},
"fastbootDependencies": [
"rsvp",
"path"
]
}The fastbootDependencies in the above example means the only node
modules your Ember app can use are rsvp and path.
If the package you are using is not built-in to Node, you must also
specify the package and a version in the package.json dependencies
hash. Built-in modules (path, fs, etc.) only need to be added to
fastbootDependencies.
From your Ember.js app, you can run FastBoot.require() to require a
package. This is identical to the CommonJS require except it checks
all requests against the whitelist first.
let path = FastBoot.require('path');
let filePath = path.join('tmp', session.getID());If you attempt to require a package that is not in the whitelist, FastBoot will raise an exception.
Note that the FastBoot global is only available when running in
FastBoot mode. You should either guard against its presence or only use
it in FastBoot-only initializers.
FastBoot registers the fastboot service. This service allows you to
check if you are running within FastBoot by checking
fastboot.isFastBoot. There is also a request object under
fastboot.request which exposes details about the current request being
handled by FastBoot
By default, FastBoot waits for the beforeModel, model, and
afterModel hooks to resolve before sending the response back to the
client. If you have asynchrony that runs outside of those contexts, your
response may not reflect the state that you want. To solve this, the
fastboot service has deferRendering function that accepts a promise.
It will chain all promises passed to it, and the FastBoot server will
wait until all of these promises resolve before sending the response to
the client. These promises must be chained before the rendering is
complete after the model hooks. For example, if a component that is
rendered into the page makes an async call for data, registering a
promise to be resolved in its init hook would allow the component to
defer the rendering of the page.
You can access cookies for the current request via fastboot.request
in the fastboot service.
export default Ember.Route.extend({
fastboot: Ember.inject.service(),
model() {
let authToken = this.get('fastboot.request.cookies.auth');
// ...
}
});The service's cookies property is an object containing the request's
cookies as key/value pairs.
You can access the headers for the current request via fastboot.request
in the fastboot service. The headers object implements part of the
Fetch API's Headers
class, the
functions available are
has,
get, and
getAll.
export default Ember.Route.extend({
fastboot: Ember.inject.service(),
model() {
let headers = this.get('fastboot.request.headers');
let xRequestHeader = headers.get('X-Request');
// ...
}
});You can access the host of the request that the current FastBoot server
is responding to via fastboot.request in the fastboot service. The
host property will return the host (example.com or localhost:3000).
export default Ember.Route.extend({
fastboot: Ember.inject.service(),
model() {
let host = this.get('fastboot.request.host');
// ...
}
});To retrieve the host of the current request, you must specify a list of
hosts that you expect in your config/environment.js:
module.exports = function(environment) {
var ENV = {
modulePrefix: 'host',
environment: environment,
baseURL: '/',
locationType: 'auto',
EmberENV: {
// ...
},
APP: {
// ...
},
fastboot: {
hostWhitelist: ['example.com', 'subdomain.example.com', /^localhost:\d+$/]
}
};
// ...
};The hostWhitelist can be a string or RegExp to match multiple hosts.
Care should be taken when using a RegExp, as the host function relies on
the Host HTTP header, which can be forged. You could potentially allow
a malicious request if your RegExp is too permissive when using the host
when making subsequent requests.
Retrieving host will error on 2 conditions:
- you do not have a
hostWhitelistdefined - the
Hostheader does not match an entry in yourhostWhitelist
You can access query parameters for the current request via fastboot.request
in the fastboot service.
export default Ember.Route.extend({
fastboot: Ember.inject.service(),
model() {
let authToken = this.get('fastboot.request.queryParams.auth');
// ...
}
});The service's queryParams property is an object containing the request's
query parameters as key/value pairs.
You can access the path (/ or /some-path) of the request that the
current FastBoot server is responding to via fastboot.request in the
fastboot service.
export default Ember.Route.extend({
fastboot: Ember.inject.service(),
model() {
let path = this.get('fastboot.request.path');
// ...
}
});You can access the protocol (http or https) of the request that the
current FastBoot server is responding to via fastboot.request in the
fastboot service.
export default Ember.Route.extend({
fastboot: Ember.inject.service(),
model() {
let protocol = this.get('fastboot.request.protocol');
// ...
}
});You can pass application state from the FastBoot rendered application to the browser rendered application using a feature called the "Shoebox". This allows you to leverage server API calls made by the FastBoot rendered application on the browser rendered application. Thus preventing you from duplicating work that the FastBoot application is performing. This should result in a performance benefit for your browser application, as it does not need to issue server API calls whose results are available from the Shoebox.
The contents of the Shoebox are written to the HTML as strings within
<script> tags by the server rendered application, which are then
consumed by the browser rendered application.
This looks like:
.
.
<script type="fastboot/shoebox" id="shoebox-main-store">
{"data":[{"attributes":{"name":"AEC Professionals"},"id":106,"type":"audience"},
{"attributes":{"name":"Components"},"id":111,"type":"audience"},
{"attributes":{"name":"Emerging Professionals"},"id":116,"type":"audience"},
{"attributes":{"name":"Independent Voters"},"id":2801,"type":"audience"},
{"attributes":{"name":"Staff"},"id":141,"type":"audience"},
{"attributes":{"name":"Students"},"id":146,"type":"audience"}]}
</script>
.
.You can add items into the shoebox with shoebox.put, and you can retrieve
items from the shoebox using shoebox.retrieve. In the example below we use
an object, shoeboxStore, that acts as our store of objects that reside in
the shoebox. We can then add/remove items from the shoeboxStore in the
FastBoot rendered application as we see fit. Then in the browser rendered
application, it will grab the shoeboxStore from the shoebox and retrieve
the record necessary for rendering this route.
export default Ember.Route.extend({
fastboot: Ember.inject.service(),
model(params) {
let shoebox = this.get('fastboot.shoebox');
let shoeboxStore = shoebox.retrieve('my-store');
if (this.get('fastboot.isFastBoot')) {
return this.store.findRecord('post', params.post_id).then(post => {
if (!shoeboxStore) {
shoeboxStore = {};
shoebox.put('my-store', shoeboxStore);
}
shoeboxStore[post.id] = post.toJSON();
});
} else {
return shoeboxStore && shoeboxStore[params.post_id];
}
}
});There are two places where the inclusion of incompatible JavaScript libraries could occur:
app.importin the application'sember-cli-build.jsapp.importin an addon'sincludedhook
ember-cli-fastboot sets the EMBER_CLI_FASTBOOT environment variable when it is
building the FastBoot version of the application. You can use this to prevent the
inclusion of the library at build time:
if (!process.env.EMBER_CLI_FASTBOOT) {
// This will only be included in the browser build
app.import('some/jquery.plugin.js')
}While FastBoot is under active development, there are several major restrictions you should be aware of. Only the most brave should even consider deploying this to production.
Since didInsertElement hooks are designed to let your component
directly manipulate the DOM, and that doesn't make sense on the server
where there is no DOM, we do not invoke either didInsertElement or
willInsertElement hooks. The only component lifecycle hooks called in
FastBoot are init, didReceiveAttrs, didUpdateAttrs and willDestroy.
Running most of jQuery requires a full DOM. Most of jQuery will just not be supported when running in FastBoot mode. One exception is network code for fetching models, which we intended to support, but doesn't work at present.
Prototype extensions do not currently work across node "realms." Fastboot applications operate in two realms, a normal node environment and a virtual machine. Passing objects that originated from the normal realm will not contain the extension methods inside of the sandbox environment. For this reason, it's encouraged to disable prototype extensions.
Due to limitations in Ember CLI, builds take twice as long to generate the second set of FastBoot assets. This also means incremental builds with live reload don't work either. This aims to be resolved by FastBoot 1.0. In the mean time, we introduce a short-circuit evironment flag to not do a FastBoot build:
FASTBOOT_DISABLED=true ember build
This is useful to keep your existing workflow while in development, while still being able to deploy FastBoot. This flag will be removed in FastBoot 1.0.
Because your app is now running in Node.js, not the browser, you'll need a new set of tools to diagnose problems when things go wrong. Here are some tips and tricks we use for debugging our own apps.
Enable verbose logging by running the FastBoot server with the following environment variables set:
DEBUG=ember-cli-fastboot:* ember fastbootPRs adding or improving logging facilities are very welcome.
You can get a debugging environment similar to the Chrome developer tools running with a FastBoot app, although it's not (yet) as easy as in the browser.
First, install the Node Inspector:
npm install node-inspector -gMake sure you install a recent release; in our experience, older versions will segfault when used in conjunction with Contextify, which FastBoot uses for sandboxing.
Next, start the inspector server. We found the experience too slow to be
usable until we discovered the --no-preload flag, which waits to
fetch the source code for a given file until it's actually needed.
node-inspector --no-preloadOnce the debug server is running, you'll want to start up the FastBoot
server with Node in debug mode. One thing about debug mode: it makes
everything much slower. Since the ember fastboot command does a full
build when launched, this becomes agonizingly slow in debug mode.
Avoid the slowness by manually running the build in normal mode, then running FastBoot in debug mode without doing a build:
ember build && node --debug-brk ./node_modules/.bin/ember fastboot --no-buildThis does a full rebuild and then starts the FastBoot server in debug
mode. Note that the --debug-brk flag will cause your app to start
paused to give you a chance to open the debugger.
Once you see the output debugger listening on port 5858, visit
http://127.0.0.1:8080/debug?port=5858
in your browser. Once it loads, click the "Resume script execution"
button (it has a ▶︎ icon) to let FastBoot continue loading.
Assuming your app loads without an exception, after a few seconds you
will see a message that FastBoot is listening on port 3000. Once you see
that, you can open a connection; any exceptions should be logged in the
console, and you can use the tools you'd expect such as console.log,
debugger statements, etc.
If you're using Node 6.4 and above, there's currently an
open issue
involving node-inspector. A fix
has been committed, and an updated version just needs to be published to NPM.
Until an updated version of node-inspector is published to NPM, you can clone
node-inspector locally, and call the appropriate script. For example, instead
of calling node-inspector, call [path to node-inspector]/bin/inspector.js
Node 6.3 is the first version to
offer support for the --inspect flag. This is intended to replace usage of
tools like node-inspector. However the --inspect flag isn't suitable for
debugging FastBoot apps because Node does not support debugging of code in a vm
module context (see this issue),
which is a module that FastBoot utilizes.
Because of this, it's recommended to use either node-inspector, or Node's out-of-process debugging utility, until a version of Node is released that resolves the above-mentioned issue.
Run the automated tests by running npm test.
Note that the integration tests create new Ember applications via ember new and thus have to run an npm install, which can take several
minutes, particularly on slow connections.
To speed up test runs you can run npm run test:precook to "precook" a
node_modules directory that will be reused across test runs.
Run the tests with the DEBUG environment variable set to
fastboot-test to see verbose debugging output.
DEBUG=fastboot-test npm test