Complex Architectures in Ember

Hi. I’m Matthew.
I build spiffy apps for clients in NYC
Thursday, September 19, 13

@mixonic
httP://madhatted.com
matt.beale@madhatted.com

Let’s go single page

AMBITIOUS

COMPLEX

Start simple.

title
body
preview submit
preview

1 <div style="clear:both">
2 <div style="float:left">
3 {{input value=title}}
4 {{textarea value=body}}
5 </div>
7 {{post-preview markdown=body}}
8 </div>
9 </div>
10
12 <button style="float:left" {{action "preview"}}>Preview</button>
13 <button style="float:left" {{action "submit"}}>Submit</button>
14 </div>

Great! HTML.

HTML dictates layout.

HTML dictate layout.
Templates

AND YOUR
ARCHITECTURE

5 </div>
8 </div>
9 </div>
10
14 </div>
ACTION DOESNT TALK TO COMPONENTS

5 </div>
8 </div>
9 </div>
10
14 </div>
CHASM OF DOM

5 </div>
7 {{post-preview markdown=body viewName="preview"}}
8 </div>
9 </div>
10
12 <button style="float:left" {{action "preview" target=view.preview}}>Preview</button>
14 </div>
WORKAROUND 1

5 </div>
7 {{view App.PostPreview markdownBinding=body viewName="preview"}}
8 </div>
9 </div>
10
14 </div>
WORKAROUND 2

5 </div>
7 {{render "post_preview" body}}
8 </div>
9 </div>
10
14 </div>
1 App.ApplicationRoute = Ember.Route.extend({
2 actions: {
3 preview: function(){
4 var controller = this.controllerFor('post_preview');
5 controller.updatePreview();
6 }
7 }
8 });
WORKAROUND 3

WORKAROUND 4
1 App.ApplicationRoute = Ember.Route.extend({
2 renderTemplate: function(){
3 this._super.apply(this, arguments);
4 this.render('post_preview', {
5 into: 'application',
6 outlet: 'preview',
7 controller: 'post_preview'
8 });
9 },
10 actions: {
11 preview: function(){
12 var app = this.controllerFor('application');
13 var preview = this.controllerFor('post_preview');
14 preview.set('markdown', app.get('body'));
15 }
16 }
17 });
18
19 App.PostPreviewController = Ember.Controller.extend();
5 </div>
7 {{outlet "preview"}}
8 </div>
9 </div>
10
14 </div>

When we pick between these
options...

We make design decisions.

•Re-usability as ui component
•re-usability as action
•If an action fires
•Where the action is handled
•The internals of preview

ARCHITECTURE

Architecture in Ember apps is
dictated by routes and templates.

Routes and templates decide how actions
propagate the controller/route tree, scope access
to dependencies, and are most subject to
external constraints.

“Understanding actions in two easy steps”

#1: Bubbling

WARNING
THEse slides describe the behavior IN rc8 and beyond.
behavior before the changes in rc8 is very similar to
what is described here, but not identical.

ACTION BUBBLING
1 var Actionable = Ember.Object.extend(Ember.ActionHandler);
2
3 var firstTarget = Actionable.create();
4
5 firstTarget.send("Wie Geht's");
6
7 // Nothing!

ACTION BUBBLING
2
3 var firstTarget = Actionable.extend({
4 actions: {
5 "Wie Geht's": function(){
6 console.log("Danke gut");
7 }
8 }
9 }).create();
10
12
13 // Danke gut

ACTION BUBBLING
2
3 var secondTarget = Actionable.extend({
4 actions: {
6 console.log("Und dir?");
7 }
8 }
9 }).create();
10
12 target: secondTarget,
13 actions: {
16 }
17 }
18 }).create();
19
21
22 // Danke gut

ACTION BUBBLING
2
4 actions: {
7 }
8 }
9 }).create();
10
13 actions: {
16 return true;
17 }
18 }
19 }).create();
20
22
23 // Danke gut
24 // Und dir?
RETUrn true to continue
bubbling the action

ACTION BUBBLING
2
4 actions: {
7 }
8 }
9 }).create();
10
13 actions: {
14 "Wie Geht's": null, // Or just don't define actions
15 }
16 }).create();
17
19
20 // Und dir?

Controllers, Routes, Views, and
Components handle actions.

Only Controllers and Routes have
targets for bubbling.

#1: ROUTES ARE stateS. Kind of.

ROUTES ARE STATES1 var moodManager = Ember.StateManager.create({
2 initialState: 'good',
3 good: Ember.State.create({
4 gut: function(){
5 console.log('Ja');
6 }
7 }),
8 bad: Ember.State.create({
9 gut: function(){
10 console.log('Nein');
11 }
12 }),
13 quiet: Ember.State.create()
14 });
15
16 moodManager.send('gut');
17 // Ja
18
19 moodManager.transitionTo('bad');
21 // Nein
22
23 moodManager.transitionTo('quiet');
25 // Uncaught Error: <Ember.StateManager:ember138> could not respond to event gut
in state quiet.

ROUTES ARE STATES1 App = Ember.Application.create();
2
3 App.Router.map(function(){
4 this.route('good');
5 this.route('bad');
6 this.route('quiet');
7 });
8
9 App.GoodRoute = Ember.Route.extend({
10 actions: { gut: function(){ console.log('Ja'); } }
11 });
12
13 App.BadRoute = Ember.Route.extend({
14 actions: { gut: function(){ console.log('Nein'); } }
15 });
16
17 App.QuietRoute = Ember.Route.extend();
1 {{! application.hbs }}
2 <a {{action "gut"}}>Gut?</a>
3 {{#link-to "good"}}Get happy{{/link-to}}
4 {{#link-to "bad"}}Get sour{{/link-to}}
5 {{#link-to "quiet"}}Get quiet{{/link-to}}

ROUTES ARE STATES1 App = Ember.Application.create();
2
7 });
8
11 });
12
13 App.BadRoute = Ember.Route.extend({
14 actions: { gut: function(){ console.log('Nein'); } }
15 });
16
17 App.QuietRoute = Ember.Route.extend();
ACTIOns always hit the
leaf route, regardless
of where they fire from

ROUTES ARE STATES
1 App = Ember.Application.create();
2
7 });
8
11 });
12
13 App.GoodController = Ember.Controller.extend({
14 actions: { gut: function(){ console.log('ignored :-('); } }
15 });
BUT the TEMPLATE DECIDES
WHICH CONTROLLERS SEE
THAT ACTION

ACTIONS ON CONTROLLERS
•couples template to controller
•should not force use of NEEDs
ACTIONS ON routes
•have access to all controllers
•handled from any template on a page

Choose where to put an action.

5 </div>
7 {{post-preview markdown=body viewName="preview"}}
8 </div>
9 </div>
10
14 </div>
setting viewName causes
a property named
“preview” to be added on
the parentview of that
view with it’s own
instance
that “preview” property
can be set as a target

•Components access nothing
•views access parentView, controller
•controllers access A target (the
route or a parent controller) AND
OTHER CONTROLLERS via needs
•routes access all controllers and
models
•CHEAT WITH REGISTER/INJECT

CHEAT WITH REGISTER/INJECT
2
3 App.inject('route', 'session', 'controller:session');
4
5 App.IndexRoute = Ember.Route.extend({
6 beforeModel: function(){
7 console.log( this.get('session.user.name') );
8 }
9 });
10
11 App.SessionController = Ember.Controller.extend({
12 user: { name: 'Bob' }
13 });

1 {{render "post"}}
2 {{render "post" post}}
3 {{component content=post}}
4 {{view App.PostView contentBinding="post"}}
5 {{template "post"}}
THIS
dictates part of your architecture

When confused about an app, look
to the templates and the routes ﬁrst.

“Controllers have lots of features!”
AKA
BUT PLEASE DON’t MAKE THEM CLEVER

“I AM SO CLEVER THAT
SOMETIMES I DON’T
UNDERSTAND A SINGLE WORD
OF WHAT I AM SAYING”
Oscar Wilde

Clever Controller 1
1 App.BooksController = Ember.ArrayController.extend({
2 needs: ['library'],
3 content: Em.computed.alias('controllers.library.books')
4 });

Clever Controller 1
1 App.BooksController = Ember.ArrayController.extend({
2 needs: ['library'],
3 content: Em.computed.alias('controllers.library.books')
4 });
assumption about library controller
Assumed to only be attached to a route (no item controller)
assumes books belong to a single library

LESS Clever Controller 1
1 App.BooksRoute = Ember.Route.extend({
2 model: function(){
3 this.modelFor('library').get('books')
4 }
5 });
6
7 // The Ember controller provided by convention is sufficient.

1 <div>
2 <ul class="tabs">
3 <li {{action "openSignIn"}}>Sign In</li>
4 <li {{action "openSignUp"}}>Sign Up</li>
5 <li {{action "openForgotPassword"}}>Forgot Password</li>
6 </ul>
7 {{#if isSignInOpen}}{{template "sign_in"}}{{/if}}
8 {{#if isSignUpOpen}}{{template "sign_up"}}{{/if}}
9 {{#if isForgotPasswordOpen}}{{template "forgot_password"}}{{/if}}
10 </div>
Clever Controller 2
1 App.SessionController = Em.Controller.extend({
2 isSignInOpen: false,
3 isSignUpOpen: false,
4 isForgotPasswordOpen: false,
5
6 actions: {
7 closeOptions: function(){
8 this.setProperties({
11 isForgotPasswordOpen: false
12 });
13 },
14 openSignIn: function(){ this.closeOptions(); this.set('isSignUpOpen', true); },
15 openSignUp: function(){ this.closeOptions(); this.set('isSignUpOpen', true); },
16 openForgotPassword: function(){ this.closeOptions(); this.set('isForgotPasswordOpen', true); }
17 }
18 });

1 <div>
2 <ul class="tabs">
6 </ul>
10 </div>
Clever Controller 2
5
6 actions: {
12 });
13 },
17 }
18 });
NOT. VERY. DRY.
NEW PANELS MUST BE ADDED ON COnTROLLER
NEW PANELS MUST BE ADDED IN TEMPLATE

1 <div>
2 <ul class="tabs">
6 </ul>
10 </div>
Clever Controller 2
5
6 actions: {
12 });
13 },
17 }
18 });
NAV & DISPLAYED PANEL TIGHTLY COUPLED
panels cannot be controlled from other scopes

1 <div>
2 <ul class="tabs">
3 <li {{bind-attr class="isSignInOpen:active"}}{{action "openPanel" "signIn"}}>Sign In</li>
4 <li {{bind-attr class="isSignUpOpen:active"}}{{action "openPanel" "signUp"}}>Sign Up</li>
5 <li {{bind-attr class="isForgotPasswordOpen:active"}}{{action "openPanel" "forgotPassword"}}>Forgot Passw
6 </ul>
7 {{outlet "panel"}}
8 </div>
1 App.SessionRoute = Ember.Router.extend({
2 setupController: function(){
3 this._super.apply(this, arguments);
4 Em.run.once(this, function(){
5 this.send('openPanel', 'signIn');
6 });
7 },
8 actions: {
9 openPanel: function(panel){
10 this.controller.set('openPanel', panel);
11 this.render('panels/'+panel, {
12 into: 'session',
13 outlet: 'panel'
14 });
15 }
16 }
17 });
18
19 App.SessionController = Ember.Controller.extend({
20 isSignInOpen: Em.computed.equal('openPanel', 'signIn'),
21 isSignUpOpen: Em.computed.equal('openPanel', 'signUp'),
22 isForgotPasswordOpen: Em.computed.equal('openPanel', 'forgotPassword')
23 });

1 {{#each controller}}
2 {{name}}
3 {{/each}}
Clever Controller 3
2
5 return Ember.A([
6 { name: 'Munster' },
7 { name: 'Alpine Lace' },
8 { name: 'Tome' }
9 ]);
10 }
11 });

2 {{name}}
3 {{/each}}
Clever Controller 3
2
5 return Ember.A([
8 { name: 'Tome' }
9 ]);
10 }
11 });
APPle invasion! apple invasion! apple invasion!

2 {{name}}
3 {{/each}}
Clever Controller 31 App = Ember.Application.create();
2
5 return Ember.A([
8 { name: 'Tome' }
9 ]);
10 }
11 });
12
13 App.IndexController = Ember.ArrayController.extend({
14 itemController: 'fruitInvasion'
15 });
16
17 App.FruitInvasionController = Ember.ObjectController.extend({
18 name: function(){
19 return 'Apple invasion!';
20 }.property()
21 });
APPle invasion! apple invasion! apple invasion!
Changes context in the
template from outside the
template.

1 {{#each controller itemController='fruitInvasion'}}
2 {{name}}
3 {{/each}}
2
5 return Ember.A([
8 { name: 'Tome' }
9 ]);
10 }
11 });
12
13 App.FruitInvasionController = Ember.ObjectController.extend({
14 name: function(){
15 return 'Apple invasion!';
16 }.property()
17 });

“TOO CLEVER IS DUMB”
Ogden Nash

TL;DR

Don’t work so hard in controllers.

Look to routes and templates for
your application architecture.

Thanks!
@mixonic
httP://madhatted.com
matt.beale@madhatted.com

Complex Architectures in Ember

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