Building Reactive, Realtime AppsWithout Writing JavaScript

Bryan Powell @bryanp

All Things Open 2015

The web should not be single-page.

We need a better way to build the web.

Collaboration

Content

Progressive enhancement is necessary when content has priority.

Sorry, web standards will win.

But isomorphic JavaScript!

Server Rendered w/ Real-Time Layer

Keep Business Logic on Server

(real-time as progressive enhancement)

(write no JavaScript)

WAT.

Example Time!!!Disclaimer: everything you’re about to see

works and is available now on GitHub.

<div data-scope="stats"> <span data-prop="active"> 1 </span>

<span data-prop="total"> 2 </span> </div>

<div data-scope="stats"> <span data-prop="active"> 1 </span>

<span data-prop="total"> 2 </span> </div>

<div data-scope="stats"> <span data-prop="active"> 1 </span>

<span data-prop="total"> 2 </span> </div>

<div data-scope="stats"> <span data-prop="active"> 1 </span>

<span data-prop="total"> 2 </span> </div>

<div data-scope="stats"> <span data-prop="active"> 1 </span>

<span data-prop="total"> 2 </span> </div>

<div data-scope="stats"> <span data-prop="active"> 1 </span>

<span data-prop="total"> 2 </span> </div>

{ active: 3,

total: 42

}

<

<div data-scope="stats"> <span data-prop="active"> 1 </span>

<span data-prop="total"> 2 </span> </div>

{ active: 3,

total: 42

}

view.scope(:stats).apply(data)

<

<div data-scope="stats"> <span data-prop="active"> 1 </span>

<span data-prop="total"> 2 </span> </div>

{ active: 3,

total: 42

}

view.scope(:stats).apply(data)

<

<div data-scope="stats"> <span data-prop="active"> 1 </span>

<span data-prop="total"> 2 </span> </div>

{ active: 3,

total: 42

}

view.scope(:stats).apply(data)

<

<div data-scope="stats"> <span data-prop="active"> 3 </span>

<span data-prop="total"> 42 </span> </div>

{ active: 3,

total: 42

}

view.scope(:stats).apply(data)

<

<div data-scope="stats"> <span data-prop="active"> 3 </span>

<span data-prop="total"> 42 </span> </div>

{ active: 3,

total: 42

}

view.scope(:stats).apply(data)

<

Non-Destructive Rendering

get '/' do view.scope(:stats).render(:display, with: data(:stats).all ).subscribe end

get '/' do view.scope(:stats).render(:display, with: data(:stats).all ).subscribe end

get '/' do view.scope(:stats).render(:display, with: data(:stats).all ).subscribe end

get '/' do view.scope(:stats).render(:display, with: data(:stats).all ).subscribe end

get '/' do view.scope(:stats).render(:display, with: data(:stats).all ).subscribe end

get '/' do view.scope(:stats).render(:display, with: data(:stats).all ).subscribe end

server

>

<

websocket

JavaScript Library

state change server> transformations>

JavaScript Library

>

<<

[ "apply", [ { "total": "4", "active": "2" } ] ] websocket

View Transformation Protocol

View Transformation ProtocolBusiness logic is written once, stays on the server.

View Transformation ProtocolFaster since we render only the changes.

View Transformation ProtocolThe real-time web as progressive enhancement.

mutable

server> transformations> >

<<

state change

websocket

Simple State Propagation

Simple State PropagationAll changes in view state come from the server.

Simple State PropagationServer contains the ultimate truth, client follows.

Simple State PropagationPrioritizes user trust over performance.

pakyow.org

pakyow.org

metabahn.com

@bryanp

bryanp/realtime-talk