Hypermedia APIs & Self-Building Apps

What if your application had all of the information it needed from your REST API to build itself? This session will use an example RESTful Hypermedia API running locally together with a live running custom-built mobile application to demonstrate how to automate building parts of a mobile application UI from a RESTful API response alone. We will then explore techniques to customize and fine-tune the UI while still automating most of the work from the API.

Transcript

1. Vance Lucas • Co-Founder, Brightbit
   http://brightb.it
   Hypermedia APIs &
   Self-Building Apps
   

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2. Who are You?
   • Vance Lucas
   • http://vancelucas.com
   • @vlucas (for heckling)
   • Brightbit
   • http://brightb.it
   • Design, Development & Consulting for
   web apps, mobile apps and APIs
   

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3. What is a REST API?
   Hypermedia API?
   

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4. Developed by Leonard Richardson
   http://martinfowler.com/articles/richardsonMaturityModel.html
   

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5. “Level 3” is a pre-
   condition of REST
   Roy T. Fielding
   http://roy.gbiv.com/untangled/2008/rest-apis-must-be-hypertext-driven
   

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6. You must have
   hypermedia controls in
   your API to call it REST
   

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7. “A REST API should be entered with no prior
   knowledge beyond the initial URI (bookmark)
   and set of standardized media types that are
   appropriate for the intended audience (i.e.,
   expected to be understood by any client that
   might use the API). From that point on, all
   application state transitions must be driven by
   client selection of server-provided choices that
   are present in the received representations or
   implied by the user’s manipulation of those
   representations.”
   Roy T. Fielding
   http://roy.gbiv.com/untangled/2008/rest-apis-must-be-hypertext-driven
   

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8. What are these
   “hypermedia controls”?
   

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9. Two Key Things
   

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10. Links
    

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11. Forms
    

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12. But you can’t make
    forms in an API!
    Whhaaaaa!
    

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13. You Can. Kind of...
    

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14. JSON Schema
    http://tools.ietf.org/html/draft-zyp-json-schema-03
    

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15. JSON Schema
    {
    "description":"A person",
    "type":"object",
    "properties":{
    "name":{"type":"string"},
    "age" :{
    "type":"integer",
    "maximum":125
    }
    }
    }
    

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16. URI Templates
    RFC 6570
    http://tools.ietf.org/html/rfc6570
    

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17. URI Templates
    http://uri.com/~{username}/
    #-> http://uri.com/~fred/
    http://uri.com/dictionary/{term:1}/{term}
    #-> http://uri.com/dictionary/c/cat
    http://uri.com/search{?q,lang}
    #-> http://uri.com/search?q=cat&lang=en
    

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18. HAL Spec (Unofficial)
    http://stateless.co/hal_specification.html
    

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19. HAL Specification
    {
    "_links": {
    "self": { "href": "/orders" },
    "next": { "href": "/orders?page=2" },
    "search": { "href": "/orders?id={order_id}" }
    },
    "_embedded": {
    "order": [
    {
    "_links": {
    "self": { "href": "/orders/123" },
    "customer": { "href": "/u/bob", "title": "Bob" }
    },
    "total": 30.00,
    "currency": "USD",
    "status": "shipped",
    "placed": "2011-01-16",
    }
    ]
    }
    }
    

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20. Link “rel” Types
    http://www.iana.org/assignments/link-relations/link-
    relations.xml
    

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21. No official spec for
    linking or describing
    resources for JSON or
    XML APIs
    

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22. Too Boring; Didn’t Listen:
    Link and describe
    resources however you
    want, but be consistent.
    

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23. DEMO TIME!
    App: https://github.com/vlucas/brightbudget-app
    API: https://github.com/vlucas/brightbudget-web
    

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24. Questions?
    Rate this talk: https://joind.in/6205
    

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