Video and slides synchronized, mp3 and slide download available at URL http://bit.ly/1kYLiRR. Todd Montgomery explains using WebSocket and reactive programming in an event driven RESTful architecture for the emerging IoT world. Filmed at qconnewyork.com. Todd Montgomery is a networking hacker who has researched, designed, and built numerous protocols, messaging-oriented middleware systems, and real-time data systems, done research for NASA, contributed to the IETF and IEEE, and co-founded two startups. He currently works for Kaazing as Chief Architect.

1. Evolving REST for an
IoT World
Todd L. Montgomery
@toddlmontgomery

2. InfoQ.com: News & Community Site
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Watch the video with slide
synchronization on InfoQ.com!
http://www.infoq.com/presentations
/rest-websocket-iot

3. Presented at QCon New York
www.qconnewyork.com
Purpose of QCon
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Strategy
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- speakers and topics driving the evolution and innovation
- connecting and catalyzing the influencers and innovators
Highlights
- attended by more than 12,000 delegates since 2007
- held in 9 cities worldwide

4. @toddlmontgomery
Representational State Transfer
http://en.wikipedia.org/wiki/Representational_state_transfer

5. @toddlmontgomery
pro·to·col noun ˈprō-tə-ˌkȯl, -ˌkōl, -ˌkäl, -kəl
!
...
!
3 b : a set of conventions governing the treatment and especially the
formatting of data in an electronic communications
system <network protocols>
...
3 a : a code prescribing strict adherence to correct etiquette
and precedence (as in diplomatic exchange and in the military
services) <a breach of protocol>
!

6. @toddlmontgomery
Client - Server
Cacheable
Stateless

7. @toddlmontgomery
Uniform Interface
Hypermedia, Resources,
URIs
Layered
Hmmm…

8. @toddlmontgomery
REST Ecosystem

9. @toddlmontgomery
Tools - CLI
Browser
JSON
Fast, Easy
Integration
HTTP/1.1,TCP,
[TLS/SSL], IP

10. @toddlmontgomery
IoT/IoE Ecosystem

11. @toddlmontgomery
Boards & Kits
Environments
JSON
??
Evolving
Rapidly
HTTP/1.1
TLS/SSL?
TCP
IP
Bluetooth
MQTT
SCADA
Application
App? App
Multiple
Stacks

12. @toddlmontgomery
Communication Patterns
Request/Response
Streaming “Ingest”
Publish/Subscribe
Request/Response

13. @toddlmontgomery
History & Evolution

14. @toddlmontgomery
Request
Response
HTTP
RFC 2068, 2616, …, 7230-7240
Synchronous
Request/Response
Bi-Directional… kinda,
but…
Event
Event
… only
one direction
at-a-time
June 2014

15. @toddlmontgomery
Request
Response
Delay
Delay
Processing
What happens
here while
waiting?
…Nothing…
Stop-and-Wait
HTTP

16. @toddlmontgomery
image courtesy www.tensator.com
Head-Of-Line
Blocking

17. @toddlmontgomery
Latency Sensitivity

18. @toddlmontgomery
Mobile
“OK” Bandwidth + Long RTT + High Loss Rate + No Effective HTTP Pipelining
http://en.wikipedia.org/wiki/HTTP_pipelining
Truly Awful User Experiences

19. @toddlmontgomery
Asynchronous Request / Response
Unlock More Reactive Patterns!

20. @toddlmontgomery
Request
ACK
Response
ACK
Sync
Request
Sync
Response
Web Services
…
But… Async Request/Response… kinda
Event
Event
http://en.wikipedia.org/wiki/List_of_web_service_specifications
No, seriously,
lots of these!!

21. @toddlmontgomery
Thankfully, Locked within the
Enterprise…
Mostly…

22. @toddlmontgomery
“Yeah, yeah, but your scientists
were so preoccupied with whether
or not they could that they didn't
stop to think if they should.”
— Jurassic Park
Philosophy of some REST APIs
Just because you could use
HTTP, doesn’t mean you should…

23. @toddlmontgomery
HTCPCP
RFC 2324, Extended by RFC 7168
http://en.wikipedia.org/wiki/Hyper_Text_Coffee_Pot_Control_Protocol
"there is a strong, dark, rich requirement for a protocol designed
espressoly [sic] for the brewing of coffee"

24. @toddlmontgomery

25. @toddlmontgomery
418 I’m a teapot
BREW
WHEN
"This has a serious purpose – it identifies
many of the ways in which HTTP has
been extended inappropriately.”
— Larry Masinter, author
http://larry.masinter.net/

26. @toddlmontgomery
Why is HTTP used?
Easy firewall traversal
Simple, Flexible, Familiar
Works with Anything
Addressing
Tooling

27. @toddlmontgomery
Communication Patterns
Request/Response
Streaming “Ingest”
Publish/Subscribe
Request/Response

28. @toddlmontgomery
Request
Response
Support
(UI/Device)
Security
(Challenge)
Keep-Alive
or Watchdog
User State
Query

29. @toddlmontgomery
Battery Life
Persistent connections help a LOT!
Well designed protocols help a LOT MORE!
Many simultaneous connections hurt!
Using the wrong protocol with the wrong pattern hurts A LOT!
The Wrong Patterns Hurt a LOT!
Stay out of High
Energy State!

30. @toddlmontgomery
New
Protocols & Standards

31. @toddlmontgomery
Async
Request/
Response
Streaming
WebSocket
RFC 6455
Full Duplex, Asynchronous
“TCP over the Web”
EventsEvents
101 Switch
HTTP Upgrade
Ingest
https://tools.ietf.org/html/rfc6455
Really a
Transport
Protocol

32. @toddlmontgomery
Async
Request
Async
Response
SPDY & HTTP/2
IETF Drafts
Async Request/Response
Multiple Streams
Efficient Headers (HPACK)
Binary Encoding
Events
Events
http://www.ietf.org/id/draft-ietf-httpbis-http2-12.txt

33. @toddlmontgomery
Async
Request
Async
Response
WebSocket over HTTP/2
IETF Draft
Streaming Ingest
Full Duplex, Asynchronous
with Multiple Channels/Streams
Events
Events
http://www.ietf.org/id/draft-hirano-httpbis-websocket-over-http2-00.txt

34. @toddlmontgomery
MQ Telemetry Transport (MQTT)
http://mqtt.org/
Lightweight
Publish/Subscribe
Messaging Transport
Runs over TCP
or WebSocket (v3.1.1)
MQTT-SN for non-TCP/IP
Broker-Based
OASIS Standard

35. @toddlmontgomery
Constrained Application Protocol
(CoAP)
http://www.ietf.org/id/draft-ietf-core-coap-18.txt
Runs over UDP, DTLS,
or WebSocket
Request/Response
(either direction),
Publish/Subscribe
Standardized HTTP
Mapping
Resource Discovery,
Linking, etc.
IETF CoRE WG (Constrained RESTful Environments)

36. @toddlmontgomery
Sustain REST Principles
Standards-BasedEasily Parsed
Efficient Handling of Data/Metadata
Flexible - Easily ExtendedEasy to Implement
Requirements

37. @toddlmontgomery
Possible Game Plan(s)
WebSocket + MQTTHTTP/2
WebSocket + CoAP WebSocket + HPACK
Combining IoT & REST

38. @toddlmontgomery
HTTP/2
Nothing Optional,
TLS, HPACK, etc.
Familiar Primitives
More complex
than HTTP/1.1
Ecosystems:
REST Yes,
IoT No

39. @toddlmontgomery
WebSocket + MQTT
HTTP Mapping?
WebSocket can adapt
Some Guaranteed
Messaging Semantics
Ecosystems:
IoT Yes,
REST No (w/o WS)
Enables Many
Patterns

40. @toddlmontgomery
WebSocket + HPACK
http://www.ietf.org/id/draft-ietf-httpbis-header-compression-07.txt
HPACK handles
method + headers
Use header for
Stream ID
Not a Standard,
but made of
Standards
HPACK is
(subjectively)
complex

41. @toddlmontgomery
WebSocket + CoAP
http://www.ietf.org/id/draft-savolainen-core-coap-websockets-02.txt
HTTP Mapping
Ecosystems:
REST Yes,
IoT Yes
No
Guaranteed
Messaging
Not Broker-based,
Peer-to-Peer

42. @toddlmontgomery
One More Thing…
!
JSON

43. @toddlmontgomery
Binary Encoding
Thing 1 Thing 2
Not a human Also, …not a human
Does not need to be
human readable
http://tools.ietf.org/html/rfc7049
Concise Binary Object Representation (COBR)
FIX / Simple Binary Encoding (SBE)
https://github.com/real-logic/simple-binary-encoding
HPACK (Part of HTTP/2)

44. @toddlmontgomery
Questions?
• Kaazing http://www.kaazing.com
• Slideshare http://www.slideshare.com/toddleemontgomery
• Twitter @toddlmontgomery
Thank You!

45. Watch the video with slide synchronization on
InfoQ.com!
http://www.infoq.com/presentations/rest-
websocket-iot