Web Services REST-Style: Universal Identifiers, Formats & Protocols
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Agenda

- What's REST?
- Universal Identifiers, Formats & Protocols
- The Holy REST Trinity - Noun, Verbs, Types
- REST Design Principles 
- Architecture Astronaut REST Speak


What's REST?
============

Representational State Transfer (REST) - Meaningless Acronym? Wordplay?

rest - n. - peace, ease, or refreshment resulting from the insight that the web works

No matter what vendors tell you - no need to "Light Up the Web" - relax - built on an **open architecture using universal identifiers, formats & protocols and _evolving_ open standards** - no need to reinvent the wheel and sign-up for single-vendor offerings.

### Broad Definition

- Best Practices for Designing Web Services for a Unified Human and Programable Web

### Narrow Definition

- Alternative to BigCo Web Services (SOAP, WS-STAR) and RPC-Style Web Services (XML-RPC)

### Resource, Representation, State, Transfer

- (Stateless) Resource Representation -> Open Format + Identifier e.g. HTML+URI
- Transfer Rules (Protocol) e.g. HTTP


Universal Identifiers, Formats & Protocols - The Holy Trinity
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- Identifiers -> URLs (Uniform Resource Locator), URIs (Uniform Resource Identifier)
- Formats -> HTML (HyperText Markup Language), XML (Extensible Markup Language)
- Protocols -> HTTP (HyperText Transfer Protocol), AtomPub (Atom Publishing Protocol)


The Holy REST Trinity - Noun, Verbs, Types
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REST-Speak -  Internet-Speak  - Plain Old English

- Verbs  -> Protocols    -> Communication & Data Exchange Rules
- Nouns  -> Identifiers  -> Names, Addresses
- Types  -> Formats      -> Documents, Feeds, Photos, Videos, Music, etc.

Examples:
- Verbs -> HTTP GET, POST, PUT, DELETE
- Nouns -> `flickr.com/photos/tag/vancouver`, `deli.cio.us/vanajax/tag/libraries`, etcetera
- Types -> HTML, RSS, PNG, etcetera


REST Design Principles - What's REST?
=====================================

- Idenifiers Matter - Choose Great Names
- Open Formats Matter - Avoid Vendor Lock-In
- Protocols Matter - Learn more about HTTP and Use Best Practices
    - Use HTTP GET for Read-Only/Side-Effect-Free Requests
    - Use HTTP Accept Headers for Format Selection
    - Use Full HTTP Method Vocabulary (GET, POST, PUT, DELETE)

More:
- No Web without Linking and No Linking without Identifiers!
- (Stateless) Resource Representation -> Open Format + Identifier e.g. HTML+URI


Architecture Astronaut REST Speak
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- REST-y
- REST-ful

Or:
- Resource-Oriented Architecure (ROA)
- Web-Oriented Architecure (WOA)

Or:
- REST-RPC-Hybrid (Three Web Service Architectures):
    - 1) REST
    - 2) REST-RPC Hybrid
    - 3) RPC (Remote Procedure Call)