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© 2 0 1 4 M a s h e r y , I n c . — P R O P R I E T A R Y A N D C O N F I D E N T I A L© 2 0 1 4 M a s h e r y , I n c . — P R O P R I E T A R Y A N D C O N F I D E N T I A L
Taming The RESTed NARWHL
Striking the Balance Between
Usability and Zealotry in REST

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Is this RESTful?
http://api.example.com/events/query.json?id=87465

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© 2 0 1 4 M a s h e r y , I n c . — P R O P R I E T A R Y A N D C O N F I D E N T I A L
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What About This?
Find “Rob Zazueta” in the employee Database.
GET /countries
[
"/countries/usa/states",
"/countries/can/provinces",
...
]
GET /countries/usa/states
[
"/countries/usa/states/al",
"/countries/usa/states/ak",
...
]
GET /countries/usa/states/ca
[
"/countries/usa/states/ca/divisions",
"/countries/usa/states/ca/employees",
...
]
GET /countries/usa/states/ca/employees
[
"/countries/usa/states/ca/employees/alan_akbar",
"/countries/usa/states/ca/employees/bill_allen"
...
]

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© 2 0 1 4 M a s h e r y , I n c . — P R O P R I E T A R Y A N D C O N F I D E N T I A L
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“What is a REST API?”

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© 2 0 1 4 M a s h e r y , I n c . — P R O P R I E T A R Y A N D C O N F I D E N T I A L
A design framework to build RESTful
APIs intended for consumption by
applications built by people
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Introducing the RESTed NARWHL

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© 2 0 1 4 M a s h e r y , I n c . — P R O P R I E T A R Y A N D C O N F I D E N T I A L
The RESTed NARWHL
http://www.narwhl.com
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PLEASE PROVIDE YOUR FEEDBACK!

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© 2 0 1 4 M a s h e r y , I n c . — P R O P R I E T A R Y A N D C O N F I D E N T I A L
Noun
As
Resource
With
Hyper
Links
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1. It’s how I describe intuitive APIs

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2. Narwhals are an awesome mashup
+ =

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3. Narwhals are real.

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Obligatory RMM Slide
Source: http://martinfowler.com/articles/richardsonMaturityModel.html

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© 2 0 1 4 M a s h e r y , I n c . — P R O P R I E T A R Y A N D C O N F I D E N T I A L
• A customer wants to browse for products by
category.
• A customer wants to add a product to their
shopping cart.
• A store admin wants to list all customers who
bought a given product.
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Use Cases Uncover Resources

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© 2 0 1 4 M a s h e r y , I n c . — P R O P R I E T A R Y A N D C O N F I D E N T I A L
• A customer wants to browse for products by
category.
• A customer wants to add a product to their
shopping cart.
• A store admin wants to list all customers who
bought a given product.
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Use Cases Uncover Resources

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© 2 0 1 4 M a s h e r y , I n c . — P R O P R I E T A R Y A N D C O N F I D E N T I A L
• Customers
• Products
• Categories
• Shopping Cart
• Store Admin
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Use Cases Uncover Resources

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Endpoint Design Matters
/{resource_name}/{resource_identifier}

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Endpoint Design Matters
/products/73924

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Endpoint Design Matters
/categories/39/products/73924

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Endpoint Design Matters
Link: <http://api.example.com/v1/products/73924>; rel="canonical"

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© 2 0 1 4 M a s h e r y , I n c . — P R O P R I E T A R Y A N D C O N F I D E N T I A L
Start using specific MIME types in your
responses – even custom ones.
NO - Content-Type: text/json
YES – Content-Type:
application/vnd.example.products.json+v1
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Saner Versioning Through Content Negotiation

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© 2 0 1 4 M a s h e r y , I n c . — P R O P R I E T A R Y A N D C O N F I D E N T I A L
SDKs Suck Because:
• They’re one more thing to maintain
• They often assume functionality outside the API
• They get bloated
21Dynamic Client Generation Through Response Profiles

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© 2 0 1 4 M a s h e r y , I n c . — P R O P R I E T A R Y A N D C O N F I D E N T I A L
Dynamic Code Libraries Rock Because:
• They reflect only what’s defined in the API
• They grow and change as the API iterates
• They feel more native to the developer
22Dynamic Client Generation Through Response Profiles

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NARWHL Maturity Model*
Level 0: Nouns as Resources With Hyperlinks
Level 1: NARWHL JSON Responses
Level 2: Content Negotiation
Level 3: Response Profiles & Definitions
Awesomeness of NARWHL
*With apologies and thanks to Martin Fowler and Leonard Richardson

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© 2 0 1 4 M a s h e r y , I n c . — P R O P R I E T A R Y A N D C O N F I D E N T I A L
The RESTed NARWHL
http://www.narwhl.com
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SERIOUSLY. DON’T MAKE ME BEG.

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