Reactive Hypermedia APIs

Kevin Swiber

CODEMASH V2.0.1.5

I Like Buzzwords

Open source platform for the Internet of Things

http://zettajs.org

APIs Suck

/data.cgi

/data.cgiN0

0BIE

.NET Remoting

.NET RemotingBR

OKEN

SOAP

SOAPSTU

PID

RESTful?

RESTful?WR

ONG

Hypermedia!

Hypermedia!NERD

Whats the problem?

The real world is complex

Feedback can be vicious

We fool ourselves into thinking all problems are the same

There is no silver bullet

Love the bomb

The 15th Standard

Back to Zetta (IoT)

Reaching the Edge

DevicesDevicesDevices

Zetta

Zetta

DevicesDevicesDevices

Zetta

ClientsClientsClients

ClientsClientsClients Local Network

Data Center

Internet

The only thing we control

Desired Architectural Properties

Decoupling of implementations

Independent evolution

Scale

Load balancing

Centralize complexity, distribute simplicity

Reduce latency

Support event streams

Architectural Constraints Client-server, stateless, cacheable, layered

system, uniform interface, etc.

Wait, isnt that REST?

The hypest of all media!

http://sirenspec.org

What about event streams?

How streams are done over HTTP today

WebHooks

Chunked Transfer-Encoding

HTTP Pipelining

Long Polling

Server Sent Events

XXXXX

Just upgrade

Connection info is in the action parameters or link URI

mqtt://example.org:8863/topic

stomp+ws://example.org/topic

amqp://example.org/topic { href: ws://example.org, protocol: custom }

It works!

Model resources as finite state machines

LED.prototype.init = function(config) { config .type('led') .state('off') .when('off', { allow: ['turn-on'] }) .when('on', { allow: ['turn-off'] }) .map('turn-on', this.turnOn) .map('turn-off', this.turnOff); };

Transitions are represented as affordances in the message.

"actions": [ { "name": "turn-on", "method": "POST", "href": ..., "fields": [ { "name": "action", "type": "hidden", "value": "turn-on" } ] } ]

We need to consume an object stream.

links: [ { title: pulse, rel: [http://rxapi.org/object-stream], href: ws://... } ]

We need to consume an object stream.

wscat -c ws://... connected (press CTRL+C to quit) < {"topic":"heartbeat/1/pulse","timestamp":1411757412119,"data":61} < {"topic":"heartbeat/1/pulse","timestamp":1411757412620,"data":65} < {"topic":"heartbeat/1/pulse","timestamp":1411757413121,"data":69} < {"topic":"heartbeat/1/pulse","timestamp":1411757413622,"data":71} < {"topic":"heartbeat/1/pulse","timestamp":1411757414124,"data":66} < {"topic":"heartbeat/1/pulse","timestamp":1411757414626,"data":64} < {"topic":"heartbeat/1/pulse","timestamp":1411757415128,"data":68} < {"topic":"heartbeat/1/pulse","timestamp":1411757415629,"data":63} < {"topic":"heartbeat/1/pulse","timestamp":1411757416130,"data":65} < {"topic":"heartbeat/1/pulse","timestamp":1411757416631,"data":63}

Monitor resource events before taking action.

links: [ { title: logs, rel: [ monitor, http://rxapi.org/object-stream ], href: ws://... } ]

Monitor resource events before taking action.

wscat -c ws://... connected (press CTRL+C to quit) < {"topic":"led/2/logs","timestamp":1411809676901,"transition":"turn-on","input":[],"properties":{"id":"2","type":"led","name":null,"state":"on"}} < {"topic":"led/2/logs","timestamp":1411809677548,"transition":"turn-off","input":[],"properties":{"id":"2","type":"led","name":null,"state":"off"}} < {"topic":"led/2/logs","timestamp":1411809678483,"transition":"turn-on","input":[],"properties":{"id":"2","type":"led","name":null,"state":"on"}} < {"topic":"led/2/logs","timestamp":1411809679126,"transition":"turn-off","input":[],"properties":{"id":"2","type":"led","name":null,"state":"off"}}

We also need binary.links: [ { rel: [http://rxapi.org/binary-stream], href: ws://..., type: video/mpeg, } ]

We also need binary.

wscat -c ws://... connected (press CTRL+C to quit) Q`rCEDDIp=`"3ss79:Yk}{` 5e\`>9%J[K89\z^> 8X Gp;WqXF h1{%O;7

We also need binary.

wscat -c ws://... connected (press CTRL+C to quit)

Reactive Clientsvar siren = require('siren'); !siren() .load('http://zetta-cloud-2.herokuapp.com') .link('http://rels.zettajs.io/peer', 'Detroit') .entity(function(e) { return e.properties.type === 'sound'; }) .link('http://rels.zettajs.io/object-stream', 'level') .monitor() .subscribe(console.log);

Reactive Clientsvar zrx = require('zrx'); !zrx() .load('http://zetta-cloud-2.herokuapp.com') .server('Detroit') .device(function(d) { return d.type === 'sound'; }) .stream('level') .subscribe(console.log);

Going Forward

Solve the producer-consumer problem.

Reactive Stream Control Protocol

Consumer controlled streams

Runs over WebSockets

Multiplex streams

URI scheme definition

Will be supported on HTTP/2 + WebSockets.

What can you do with streams?

Monitoring values over time

Distributed data processing

Event sourcing

Batches

// TODO:

Extract reactive hypermedia framework from Zetta internals.

Produce a clean specification and documentation.

Experiment with multiple languages/platform implementations.

Hit me up! kswiber@gmail.com

https://twitter.com/kevinswiber

https://linkedin.com/in/kevinswiber

https://github.com/kevinswiber