This document discusses server and client rendering of single page applications. It outlines a wish list tool that was built to track products, receive alerts, and share lists. The goals are to improve the UI, separate the wish list into microservices, and update the frontend using modern frameworks. Shared rendering concerns between server and client are discussed, along with an architecture using Node.js, Express, Backbone, Handlebars and other technologies. Challenges with routing, data fetching, caching and other areas are covered, as well as potential solutions like React and Rendr. Overall it was found to be worthwhile but still immature, requiring better frameworks.

1. WISH LIST
server and client rendering of
single page apps
Thomas Heymann
@thomasheymann
github.com/cyberthom

2. WHAT WE’VE BUILT

3. WISH LIST
• Shopping tool
• Track products
• Receive alerts
• Share lists

4. GOALS & OBJECTIVES
• Improve UI
• Pull out wish list into separate stack of services
• Update front-end code using modern frameworks and best practices
– Perfect candidate for SPA due to mutability
• Minify duplication which led to inconsistencies

5. SHARED CONCERNS
Server
Client
USER
INTERACTIONS
LOGGING
MONITORING
ROUTING
PRESENTATION
LOGIC
APPLICATION DATA
views / layout / templates
models / collections /
business rules / API calls
events / animations
SITE FURNITURE
ANALYTICS
i18n
translations / date and
currency formatting
STYLING

6. • Developers get DRY and MV*
• Users get best of both worlds:
– fully rendered pages (instant content)
– responsiveness of SPA
• Business gets SEO
• Everybody’s happy 🌈😃🎉
ENVIRONMENT AGNOSTIC

7. • EvenThoughtWorks agrees 👌
TECH RADAR
http://www.thoughtworks.com/radar/#/techniques
Client and server rendering with same code
Increasingly, HTML is rendered not only on the server but also on the client,
in the web browser. In many cases this split rendering will remain a necessity
but with the growing maturity of JavaScript templating libraries an interesting
approach has become viable: client and server rendering with same code.
HOLD ASSESS TRIAL ADOPT

8. ARCHITECTURE & TECH STACK

9. SYSTEMS OVERVIEW
WISHLIST
API
SITE FURNITURE
Aggregation Layer
Presentation Layer
API
MAGAZINE
API
CATALOGUE
Core Services
& Storage

10. TECH STACK
SERVER
CLIENT
node.js
IE8+
Express
Backbone Router
cheerio
jQuery
Backbone
Handlebars
require.js
App

11. • Renders nested views
• Re-attaches views to DOM client-side
APP COMPONENTS
VIEW ASSEMBLER
ROUTER
MODEL FACTORY
SERIALIZER
SYNCER
• Ignores duplicate requests and caches responses
• Injects headers
• Matches URLs and extracts params
• Executes controller logic
• Serializes app data to JSON server-side
• Deserializes app data client-side
• Creates models
• Enforces singletons for data bindings

12. PAGE REQUEST
1. Instantiate app
2. Dispatch route (run controller logic)
3. Render views
4. Serialize data (models/collections)
5. Decorate page with site furniture
6. Send response
SERVER WORKFLOW

13. PAGE LOAD
1. Instantiate app
2. Deserialize data (models/collections)
3. Setup Backbone routes
4. Dispatch route (run controller logic)
5. Re-attach views
PAGE NAVIGATION
1. Dispatch route (run controller logic)
2. Render views
CLIENT WORKFLOW

14. HANDS ON

15. module.exports = function(options) {!
var options = options || {},!
App = options.app,!
route = options.route;!
!
return function(req, res, next) {!
var app = new App({!
language: req.params.language,!
authToken: req.cookies.sessionid!
});!
!
app!
.dispatch(route, req.params)!
.done(function(view) {!
var html = view.render().outerHTML(),!
bootstrap = JSON.stringify(app.serialize());!
res.send(html + '<script>' + bootstrap + '</script>');!
})!
.fail(next);!
};!
};!
SERVE APP MIDDLEWARE

16. WISH LIST CONTROLLER
route('/wishlist/:id', 'wishlist', function(id) {!
var app = this, api = app.wishlistApi;!
!
var allWishlists = api.getAllWishlists(),!
wishlist = api.getWishlist(id),!
allWishlistItems = api.getAllWishlistItems(id);!
!
var productList = new ProductListView({!
collection: allWishlistItems!
}),!
navigation = new NavigationView({!
model: wishlist,!
collection: allWishlists!
});!
mainView = new MainView({!
model: wishlist,!
views: {!
'append header': navigation,!
'inner [role=main]': productList!
}!
});!
!
return mainView.ready().then(function() {!
return mainView;!
});!
});!

17. MAIN TEMPLATE
<header>!
<h1>{{name}}</h1>!
!
{{#if isOwner}}!
<button>Manage</button>!
{{/if}}!
!
{{! Navigation }}!
</header>!
!
<div role="main">{{! Product List }}</div>!

18. CLIENT-SIDE BOOTSTRAPPING
<header>!
<h1>Wish List</h1> <button>Manage</button>!
<ul class="navigation">!
<li>...</li>!
</ul>!
</header>!
<div role="main">!
<ul class=“product-list">!
<li>...</li>!
</ul>!
</div>!
!
<script>!
var app = new App();!
!
app.deserialize({bootstrap});!
!
route('/wishlist/:id', 'wishlist', function(id) {!
app!
.dispatch(route, id)!
.done(function(view) {!
view.attach('.container');!
});!
});!
Backbone.history.start();!
</script>!

19. VOILA!

20. WHAT WE’VE LEARNED

21. • Lots of code bridging differences between environments and libraries
– Introducing extra abstraction layer
• Routing is different
– Stateless server-side routing (new app instance for each request)
– Stateful client-side routing (holding on to app during page navigation)
– Express vs. Backbone routes (reversed order, paths, params)
– Redirects (302 vs. browser location)
– Serve mobile page based on user agent
• Fetching data is different (XMLHttpRequest vs. node request)
COMPLEX PROBLEM

22. • Caching is different
– Only ever fetch once per incoming request
– Tab could be left open for days
– Expire and re-fetch resources after x seconds client-side
• Error handling is different (HTTP error codes vs. popups)
• Sending email is borderline
COMPLEX PROBLEM

23. • Dependency management
– CommonJS runs client-side with browserify
– AMD runs server-side with require.js
– Both work but ideally language level support (ES6 Modules)
• Promises
– Q or jQuery Deferred
– Ideally one standard (ES6 Promises)
ES5 IMMATURITY

24. • Well known jQuery API for DOM manipulation and traversal
• Easy to pick up
• Can translate Backbone apps directly to the server
• No full blown JSDOM, but still slow
CHEERIO

25. • Airbnb Rendr
– One stop solution (Rendering, Serialization, Routing)
– Pure string concatenation using templates – Fast on the server
– Client-side rendering trashes and re-renders whole DOM (can cause
flicker and performance issues)
• Facebook React
– View rendering library (Bring your own MC)
– Virtual DOM approach: slow on the server but super fast client-side
– Fun fact: Inspired by DOOM III
CHEERIO ALTERNATIVES

26. Rendering comment box with 1000 comments
SERVER-SIDE PERFORMANCE
• Very simple HTML – String concatenation will shine even more as markup
grows in complexity
• React has the edge over Cheerio – JSX uses precompiled objects so can be
heavily optimized byV8 (Cheerio parses strings into trees on runtime)
RENDR
REACT
CHEERIO
~ 110 ms
~ 174 ms
~ 204 ms

27. • Load performance means time to content (not response time)
– Server-side DOM is slow but faster than serving empty pages
• Think of it as an enhancement to SPA
– Stateless service can be easily scaled up
– Respond with empty pages if load is too high and render client-side
• Client-side rendering performance equally important
• Decide per use case – In certain situations simple Express.js templating with
separate client-side JS might be better approach
SO WHAT?

28. • YES! 🌟😺✨
• Joy to develop once hard work is done
• Easy and fast to build rich UI and add new functionality
• But:
• Technique in its infants
• Better frameworks/solutions required
WORTH IT?

29. THANKS!