Presentation by Ronnie Mitra, Principal API Architect - Europe from Layer 7 API Academy at Nordic APIs in Copenhagen. 21st May - 2013

1. My Journey into the Terrifying World of
Hypermedia
Ronnie Mitra
Principal API Architect - Europe
Layer 7 API Academy

3. API Management
virtual cloudon-premise

4. The Hypermedia Style

5. Tunnel Style
URI Style
Event Driven Style
Hypermedia Style

6. Hypermedia Style

7. Our hero
(in this story)

8. Fear

9. Will developers need to build
‘smart’ clients?

10. How hard will this be and is it
really worth it?

11. Will it help my business?

12. Why isn’t everyone doing this?

13. I need to confront hypermedia head-on!

14. www.apiacademy.co

15. Start by defining interactions

16. As a mobile app I want to..
• Retrieve a list of videos
• Retrieve a list of blogs
• Retrieve a list of featured videos
• Retrieve a list of featured blogs
• Submit user generated comments
• Retrieve comments
• Search for blogs based on criteria

20. A shot in the dark:
Defining a Media Type

21. Links to things that a client can do
Response entities
Meta information for processing

22. {
"links" : [
{
"task": "retrieve latest blogs",
"href“:"…",
"rel“:"?"
},
{
"task": "find blogs",
"href“:"…",
"rel“:"?"
}
]
}
GET /content

23. {
"links" : [
{
"task": "retrieve latest blogs",
"href":"…",
"rel" : "get-blogs"
},
{
"task": "find blogs",
"href":"…",
"rel":"find-blogs"
}
]
}
GET /content

24. Content
Collections
Content
Queries
Content
Categories

25. {
"links" : [
{
"task": “work with blogs",
"href":"…",
"rel" : "blogs"
},
{
"task": “work with video",
"href":"…",
"rel": "videos"
}
]
}
GET /content

26. {
"links" : [
{
"task": "retrieve latest blogs",
"href":"…",
"rel" : "retrieve"
},
{
"task": "find blogs",
"href":"…",
"rel":"search"
}
]
}
GET /blogs

27. Who are these relationships for?
How are they going to be used?

28. Portal
API
Design-Time/Development Time
Runtime

29. How am I going to get input from
the client?

30. {
"links" : [
{"task": "retrieve latest blogs", "href":"",
"rel":"retrieve"}
],
"search" : [
{
"task": "find blogs",
"href" : "...",
"rel" : "search",
"input-fields" : [
{"name" : "keyword", "type" : "string"},
{"name" : "publish-date", "type" : "date"}
]
}
]
}
GET /blogs

32. {
"links" : [
{"task": "retrieve latest blogs", "href":"",
"rel":"retrieve"}
],
"search" : [
{
"task": "find blogs",
"href" : "...",
"rel" : "search",
"input-fields" : [
{"name" : "keyword", "type" : "string"},
{"name" : "publish-date", "type" : "date"}
]
}
]
}
GET /blogs

33. {
"links" : [
{"task": "retrieve latest blogs", "href":"",
"rel":"retrieve"}
],
"search" : [
{
"task": "find blogs",
"href" : "...",
"rel" : "search",
"input-fields" : [
{"name" : "keyword", "type" : "string"},
{"name" : "publish-date", "type" : "date"}
{"name" : "author", "type" : “string"}
]
}
]
}
GET /blogs

34. What about the user experience?

36. {
"entities" : [
{"title": "Making Government Data Easy to Find,
Accessible & Usable", "href" : "..."},
{"title": "If They Have to Ask, You Didn’t Afford
It", "href" : "..."},
]
"links" : [
],
"search" : [
]
}

37. {
"entities" : [
{"title": "Nation Building in the Age of APIs",
"href" : "...“, “featured” : “true”},
{"title": "Making Government Data Easy to Find,
Accessible & Usable", "href" : "..."},
{"title": "If They Have to Ask, You Didn’t Afford
It", "href" : "..."},
]
"links" : [
],
"search" : [
]
}

38. Maze + XML
Collection + JSON
JSON API
HAL
SIREN
HTML
Lots of hypermedia media types

39. Wait a second…
Is this just HTML and a browser!?

40. State Transitions
Presentation
Input Fields
Render

41. State Transitions
Presentation
Input Fields
Render

42. State Transitions
Presentation
Input Fields
Render
State Transitions
Presentation
Input Fields

43. A hypermedia client strategy:
1. Parse response
2. Identify links
3. Apply handlers
4. Render

44. A different hypermedia client
strategy:
1. Parse response
2. Select relevant data
3. Follow hardcoded state
transition

45. Faithful Selective
Client Spectrum

46. Faithful Selective
Client Spectrum
Less knowledge
of application
More knowledge
of application

47. Faithful Selective
Client Spectrum
Less knowledge
of application
More knowledge
of application
Easier to change? Easier to innovate?

48. Will developers need to build
‘smart’ clients?
Not unless they need them

49. How hard will this be and is it
really worth it?
The design effort feels similar
to URI style design.
Benefits are subjective.

50. Will it help my business?
I’m still not sure.

51. Why isn’t everyone doing this?
Designing for change isn’t a
high priority?
Hypermedia isn’t a universal
tool.

52. My journey isn’t over…

53. … but it isn’t as scary as it used to be!

54. With special thanks to my
hypermedia guide
Mike Amundsen

55. My Journey into the Terrifying World of
Hypermedia
Ronnie Mitra
Principal API Architect - Europe
Layer 7 API Academy