This is from a guest lecture that I delivered to a web-programming class at Bethel University in Arden Hills, MN

1. REST
Representational State Transfer

2. whoami
Colin Harrington
● colin.harrington@objectpartners.com
● colin@colinharrington.net
● http://colinharrington.net
● @ColinHarrington

3. History
HTTP :: HyperText Transfer Protocol
Tim Berners-Lee :: 1990s
Foundations of the Web
OSI Layer 7
Application Layer
Protocol

4. History
REST :: Representational State Transfer
2000 Doctoral Dissertation by Roy T. Fielding
http://www.ics.uci.edu/~fielding/pubs/dissertation/top.htm
"Roy Thomas Fielding (born 1965) is an American computer
scientist[1], one of the principal authors of the HTTP specification, an
authority on computer network architecture[2] and co-founder of the
Apache HTTP Server project." (Wikipedia)
http://roy.gbiv.com/
@fielding

5. History - REST
Architecture:
● Client-Server
● Stateless + Cacheable
● Uniform Interface + Layerable
Data:
● Resources, identifiers & metadata
● Representation & metadata
● Control Data { headers }
Elements:
● {clients, server, resolver, cache}
● Gateways, proxies, user agents
● URL, URI, Schemes

6. REST
REST is a buzzword and a movement but it symbolizes a coherent
usage of the web (HTTP) as it was designed
REST ~ HTTP done right.

7. Resources
Uniform Resource Identifiers (URI)
<scheme>:<scheme-specified-structure>
● ftp://example.org/resource.txt
● urn:issn:1535-3613
● mailto:colin@colinharrington.net
Uniform Resource Locator (URL)
scheme://domain:port/path?query_string

8. HTTP Methods/Verbs
HEAD, GET, OPTIONS => considered "safe"
PUT, POST, DELETE => possibly destructive
TRACE, DEBUG => Considered harmful
curl -v http://www.google.com
GET / HTTP/1.1
User-Agent: curl/7.21.0
Host: www.google.com
Accept: */*

9. Accept Headers :: Client
GET / HTTP/1.1
User-Agent: curl/7.21.0
Host: www.google.com
Accept: */*
Accept: application/xml
Accept: text/html,application/xhtml+xml,
application/xml;q=0.9,*/*;q=0.8,
application/json

10. HTTP Status Codes
200 - OK
301 - Moved permanently
302 - Moved temporarily
404 - Not Found
500
http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html
HTTP/1.1 200 OK
Date: Mon, 31 Oct 2011 16:07:53 GMT
Expires: -1
Cache-Control: private, max-age=0
Content-Type: text/html; charset=ISO-8859-1

11. http://homestarrunner.com/404d

12. Representations
JSON Example
● XML {
"firstName": "John",
"lastName" : "Smith",
"age" : 25,
● JSON "address" :
{
"streetAddress": "21 2nd Street",
"city" : "New York",
● HTML "state" : "NY",
"postalCode" : "10021"
},
"phoneNumber":
● XHTML [
{
"type" : "home",
"number": "212 555-1234"
● RDF },
{
"type" : "fax",
"number": "646 555-4567"
● Text ]
}
}
● Custom Formats

13. Content Negotiation
Request:
Accept Header
Accept: application/xml
Accept-Language
Accept-Encoding
Response:
Content-Type: text/json
Accept: text/html,application/xhtml+xml,
application/xml;q=0.9,*/*;q=0.8,
application/json

14. Cacheability
HTTP Cache Headers
● Expires
● Cache-Control
● ETag
● Last-Modified
● Pragma no-cache
Proxy & Network path.

15. CRUD
Create :: POST
Read :: GET
Update :: PUT
Delete :: DELETE
* http://stackoverflow.com/questions/630453/put-vs-post-in-rest

16. Hypermedia
Linking
to other resources / media
HTML documents, resources
loosely coupled
Images, CSS, favicon, etc.
Like this image ->
http://cuip.uchicago.edu/~cac/images/Hypermedia.jpg

17. Who
http://www.programmableweb.com/
Amazon Web Services
{S3, EC2, SQS, RDS, FPS, etc.}
Just to name a few...

18. Resources
This guy explains REST in to his non-technical wife:
http://tomayko.com/writings/rest-to-my-wife
Good article on how to REST with curl:
http://blogs.plexibus.com/2009/01/15/rest-esting-with-curl/
Poster -- the Firefox plugin:
https://addons.mozilla.org/en-US/firefox/addon/poster/
You'd probably learn best by actually making some RESTful
calls. Pick a service that is free and RESTful and play around with it. I'd
recommend using http://www.twilio.com/ just because they offer you
$30 in free credit and you get to make, receive and control real phone
calls.

19. Thank You