The document discusses HTTP methods in relation to RESTful APIs, highlighting the differences between GET and POST requests, particularly focusing on idempotence as a key distinction. It explains that GET is idempotent and safe, while POST is not, which affects web scalability. Additionally, it touches on other HTTP methods like PUT and PATCH, addressing common misconceptions and their practical applications in API design.

1. HTTP Methods
How They Relate to RESTful API's

2. About Me
Herman J. Radtke III
Web Architect at HauteLook
Design the RESTful API
Writing PHP for 9 years
Maintain pecl/gearman and pecl/memcache

3. Perspective
HauteLook's API is for internal use
Very few restrictions on design
Example: Netflix
Many companies have an external API
Concerned with how the design affects
other clients (ex: flash)
Examples: Twilio, Jira, Facebook

4. Why?
REST is an architectural style
Not satisfied with the existing explanations

5. GET vs POST
Do we actually know the differences?

6. GET vs POST
I ask every interviewee this question.
Common answers:
GET does not send a body in the request
POST can send more data
POST is more secure

7. Idempotence
Idempotence means no side-effects.
This is the most important difference!
GET is idempotent (safe)
POST is not idempotent (unsafe)
It allows the web to scale.

8. Improper use of GET
<a href=”/logout.php”>Logout</a>
We just broke the internet
Caching proxies
Browser "accelerator" plugins
Better to use a form with the POST method
Other example: Tracking Pixels

9. POST vs PUT
POST is create and PUT is update, right?
Not so simple
Methods do not map to CRUD
CRUD can map to the methods
Key difference?
PUT is idempotent!

10. Create Using POST

11. Create Using PUT

12. Update Using POST 1/2

13. Update Using POST 2/2

14. Update Using PUT

15. Other HTTP Methods
PATCH
DELETE
HEAD
OPTIONS

16. Additional Resources
RFC 2616 Method Definitions - http://www.
w3.org/Protocols/rfc2616/rfc2616-sec9.html
#rest on freenode
My twitter - @hermanradtke