The document discusses designing APIs for the Internet of Things (IoT). It outlines challenges with existing IoT connectivity models and APIs. It proposes a reactive hypermedia approach using state transitions and event streams over HTTP. This involves modeling IoT resources as finite state machines and consuming object and binary streams. Reactive clients are demonstrated using a Siren and ZRX library. The document also discusses topics like managing device identity, security, and working with constrained devices. It promotes further work on extracting the reactive hypermedia approach into a specification and multiple implementations.

1. Designing an API for the
Internet of Things
Kevin Swiber

2. Open source platform for
the Internet of Things
http://zettajs.org

3. Overview

4. Ubiquitous Computing

5. Like control systems
Sensor Actuator
Controller
Environment
The Internet
…but on the Internet

6. More than 50B connected
devices by 2020

7. Maturity Scale

8. The Web

9. Mobile

10. Things

11. 3 Models of Connectivity

12. The Hub
DevicesDevicesDevices
Hub
Cloud Components
DevicesDevicesDevices
Hub
ClientsClientsClients
ClientsClientsClients Local Network
Data Center
Internet

13. The Bridge
DevicesDevicesDevices
Bridge
Cloud Components
DevicesDevicesDevices
Bridge
ClientsClientsClients
Local Network
Data Center
Internet

14. The IP-Connected Device
Device
Cloud Components
Device
ClientsClientsClients
Local Network
Data Center
Internet

15. APIs Suck

16. /data.cgi

17. /data.cgi
N00BIE

18. .NET Remoting

19. .NET Remoting
BROKEN

20. SOAP

21. SOAP
STUPID

22. RESTful?

23. RESTful?
WRONG

24. Hypermedia!

25. Hypermedia!NERD

26. What’s the problem?

27. The real world is complex

28. Feedback can be vicious

29. We fool ourselves into thinking
all problems are the same

31. There is no silver bullet

32. Love the bomb

33. The 15th Standard

34. Back to Zetta (IoT)

35. Reaching the Edge
DevicesDevicesDevices
Zetta
Zetta
DevicesDevicesDevices
Zetta
ClientsClientsClients
ClientsClientsClients Local Network
Data Center
Internet
The only thing we control

36. Desired Architectural
Properties
• Decoupling of implementations
• Independent evolution
• Scale
• Load balancing
• Centralize complexity, distribute simplicity
• Reduce latency
• Support event streams

37. Architectural Constraints
• Client-server, stateless, cacheable, layered
system, uniform interface, etc.
Wait, isn’t that REST?

38. The hypest of all media!
http://sirenspec.org

39. What about event streams?

40. How streams are done over
HTTP today
• WebHooks
• Chunked Transfer-Encoding
• HTTP Pipelining
• Long Polling
• Server Sent Events
X
X
X
X
X

41. Just upgrade

42. 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” }

43. It works!

44. 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);
};

45. Transitions are represented as
affordances in the message.
"actions": [
{
"name": "turn-on",
"method": "POST",
"href": “...”,
"fields": [
{
"name": "action",
"type": "hidden",
"value": "turn-on"
}
]
}
]

46. We need to consume an
object stream.
links: [
{
title: “pulse“,
rel: [“http://rxapi.org/object-stream“],
href: “ws://...”
}
]

47. 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}

48. Monitor resource events
before taking action.
links: [
{
title: “logs“,
rel: [
“monitor“,
“http://rxapi.org/object-stream“
],
href: “ws://...”
}
]

49. 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"}}

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

51. We also need binary.
» wscat -c ws://...
connected (press CTRL+C to quit)
Q`rCEDˌDIp=`"3ss79:Yk}{` 5e`>9%J[K89z^> 8X Gp;W̮qXF
h1{%O;7<Bi‫.ڞ‬r r5
vyeK[X@ƯDRmT:uLz[ V
.vK",,u!N8֝=LQ=s~ӆ`]{E6[
WȝM]3Uo|&n
Њmo('/K>2칩e,l{%`:<rtN|SXu曆psFJS*s#AB]ý0Rt_`uS}vX3ctA>kJfuΎ^L๖ V"u8GU
‫*ڹ‬

52. We also need binary.
» wscat -c ws://...
connected (press CTRL+C to quit)

53. Reactive Clients
var 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);

54. Reactive Clients
var 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);

55. Reactive Stream Control
Protocol
• Consumer controlled streams
• Runs over WebSockets
• Multiplex streams

56. What can you do with
streams?
• Monitoring values over time
• Distributed data processing
• Event sourcing
• Batches

57. Going Forward

58. // TODO:
• Extract reactive hypermedia framework from
Zetta internals.
• Produce a clean specification and
documentation.
• Experiment with multiple languages/platform
implementations.

59. Additional Topics
• Managing device identity
• Security along the entire stack
• Working in an occasionally connected
environment
• Working with highly constrained devices
• Enterprise IoT

60. Open source platform for
the Internet of Things
http://zettajs.org

61. Hit me up!
• kswiber@gmail.com
• https://twitter.com/kevinswiber
• https://linkedin.com/in/kevinswiber
• https://github.com/kevinswiber