Kirsten Jones gave a presentation on demystifying REST and debugging API calls. She provided an overview of HTTP, including requests, responses, and status codes. She explained how REST leverages HTTP to define resources and standard operations. The presentation included examples of making REST API calls using tools like HTTPScoop and examining the requests and responses. Jones concluded with tips for troubleshooting API calls and preventing problems.

1. Demystifying REST
Kirsten Jones, API Ninja, 3Scale

2. Kirsten Jones - @synedra
API Ninja (that’s me!)
 Developer Evangelist
 Worked at Netflix, LinkedIn
 Lots of experience helping developers
 Language Polyglot
 Where I came from...
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3. Kirsten Jones - @synedra
This talk
 HTTP - Quick Overview
 REST Web Services
 Debugging Tips and Techniques

4. Kirsten Jones - @synedra
Want to play along?
 HTTPScoop
 Macintosh only
 Pretty (my favorite)
 Doesn’t support SSL
 http://www.tuffcode.com
 Fiddler
 Windows only
 Supports SSL
 http://fiddler2.com
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5. Kirsten Jones - @synedra
HTTP
 HyperText Transfer Protocol
 Used for conversations between web
clients and servers
 Supports verbs for GET, PUT, POST,
DELETE
 Includes support for query parameters

6. Kirsten Jones - @synedra
How does HTTP Work?
 Client sends a request
 Method
 URL
 Headers
 Parameters
 Body
 Server replies with a response
 Content
 Status
 Headers

7. Kirsten Jones - @synedra
What do you Mean, Status?
HTTP response codes for dummies.
 50x: we f*cked up.
 40x: you f*cked up.
 30x: ask that dude over there.
 20x: cool.
Props to @DanaDanger for that one

8. Kirsten Jones - @synedra
An example request
 Chrome browser sends a request to Google
 Method: GET
 URL: http://www.google.com
 Headers:
▪ Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/
*;q=0.8
▪ Accept-Language: en-US,en;q=0.8
▪ Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3
▪ Connection: keep-alive
▪ User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_3)
AppleWebKit/535.19 (KHTML, like Gecko) Chrome/18.0.1025.168
Safari/535.19
▪ Accept-Encoding: gzip,deflate,sdch
▪ Cookie:
NID=59=EudJ2a15ql8832PCysQA0qchtuvGWMoA7rkp79VpIYAQ8-
j42IO17LFudCYNMXm9l6SHcu3YgrGRCdrRCyM468xPZaOek4Pi-
AXQ8eARqU1SGYx6y7_9LW-c3HHb-vs2;

9. Kirsten Jones - @synedra
Example Response
 Google sends a response
 Headers:
▪ Content-Length: 24716
▪ Content-Encoding: gzip
▪ Set-Cookie: NID=59=F48kbwfwOi-qCHJyrnMSUlDBVxK-
ZVKZpq5B5jttt_25IRN4lS-0rQcVttq-
dnOIlQzafw1i4HPQAO0RpZ7NuC0WCKWta7SYoekx0--
YGf2zIFZ9VXIKS-_UEaOH9iBe; expires=Sat, 10-Nov-2012 21:26:46
GMT; path=/; domain=.google.com; HttpOnly
▪ Expires: -1
▪ Server: gws
▪ X-XSS-Protection: 1; mode=block
▪ Cache-Control: private, max-age=0
▪ X-Frame-Options: SAMEORIGIN
▪ Content-Type: text/html; charset=UTF-8
▪ Date: Fri, 11 May 2012 21:26:46 GMT
 Content: A bunch of HTML
 Status: 200

10. Kirsten Jones - @synedra
Example: HTTPScoop
Request

11. Kirsten Jones - @synedra
Example: HTTPScoop
Headers

12. Kirsten Jones - @synedra
Example: HTTPScoop
Request/Response

13. Kirsten Jones - @synedra
REST APIs Leverage HTTP
 Uses URL paths to define resources
 Create, Read, Update, Delete
 POST, GET, PUT, DELETE
 Error Codes
 HTTP Status Codes
 Request parameters
 Query parameters
 Response types and configuration
 Headers

14. Kirsten Jones - @synedra
Example REST Request
 Blog Info from Tumblr
 GET (read) http://api.tumblr.com/v2/
blog/synedra.tumbler.com/info
 Requires api_key sent as parameter

15. Kirsten Jones - @synedra
Example Request:

16. Kirsten Jones - @synedra
Example Request:
 Headers

17. Kirsten Jones - @synedra
Example Request:
 Request/Response

18. Kirsten Jones - @synedra
Example REST Response
Status: 200
Content:
{"meta":
{"status":200,"msg":"OK”},
"response":{
"blog":{"title":"Untitled","posts":0,
"name":"synedra",
"url":"http://synedra.tumblr.com/",
"updated":0,
"description":"","ask":false,"likes":0}}}

19. Kirsten Jones - @synedra
Troubleshooting API Calls
 HTTPScoop to understand your calls
 Compare against a known good call
 Simplify request (weird chars?)
 Try a different (simpler) resource
 Ask good questions
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20. Kirsten Jones - @synedra
PreventingPreventableProblems
 Use existing libraries/code/examples
 Code Defensively
 Test Defensively
 Test Frequently
 Handle Errors Gracefully
 Pass back errors/log issues
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21. Kirsten Jones - @synedra
Questions?
Information about me:
 @synedra on twitter
 kirsten@3scale.net
 http://www.princesspolymath.com
 API Strategy Conference (Oct. 23-25)
Thanks to Twilio!!!
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