Web services are a treasure trove of tools, content and data. I'll be exploring how we can use Drupal's frameworks to tap into these services. From strategy and selecting the right approach, to triggering, encoding and sending HTTP messages, I'll walk through how you might go about writing a custom integration that puts your Drupal build into a conversation with the outside world. I'll follow up with real world examples I've built to interact with NASA's ECHO Earth science data service (http://earthdata.nasa.gov/echo) and the Agile Zen project management tool (http://agilezen.com). Sandboxes for the code demoed in this session are available at: * ECHO - http://drupal.org/sandbox/dbassendine/1829568 * AgileZen - http://drupal.org/sandbox/dbassendine/1828082 Presented by David Bassendine on 10/27/2012 at Drupalcamp Atlanta (https://www.drupalcampatlanta.com/session/talking-web-services).

1. Talking to Web Services
The outside world from Drupal

2. Me
David Bassendine
Senior Developer
Day: Mediacurrent
Night: Science & Sustainability
@dbassendine
linkedin.com/in/dbassendine

3. "Web Services"
open data: science, gov. & development
social: the big conversation
business tools: customers, pm, seo
... (very) big data (and growing)

4. compfight.com

5. monitter.com

6. http://goo.gl/bCkJf

7. http://goo.gl/gkuDS

8. agilezen.com

9. campaignmonitor.com image:http://goo.gl/qlQQ8

10. The task ahead ...

11. Creative Commons (CC BY 2.0) by Flickr user mariachily http://goo.gl/iU8aI

12. http://reverb.echo.nasa.gov/

13. agilezen.com

14. Step 0
Is there a module for that?

15. Step 1
HTTP and REST

16. 1: HTTP Comm.s

17. 1: HTTP Comm.s

18. 1: REST architectures
REST SOAP (XMLRPC)
Resources URIs Custom (data packet)
Methods HTTP verbs Custom (data packet)
Errors HTTP codes Custom (data packet)
Data encoding JSON / XML XML
Consistent*, chatty Flexible but inconsistent
REST vs/ SOAP: http://en.wikipedia.org/wiki/Representational_state_transfer
REST for your wife: http://tomayko.com/writings/rest-to-my-wife
REST hypermedia: http://martinfowler.com/articles/richardsonMaturityModel.html

19. Step 2
API Documentation
URLs and path structure
Authentication
Resources
Data formats

20. 2: API Documentation
Agile Zen ECHO
URL Structure RESTful RESTful
Authentication Required: Header or Not required for search
Parameter token
Resources Stories, Projects ... Datasets, Granules...
Data formats JSON XML JSON/XML (GET)
XML AQL (POST)
dev.agilezen.com http://goo.gl/b38dJ

21. Step 3
Test in the browser
GET test (simple URL) – eg. http://goo.gl/XUFtn
POSTer test (browser plugin) – Chrome: XHR POSTer
– Firefox: Poster

22. Step 4
Plan the approach

23. 4: Approaches
Drupal core HTTP
http://goo.gl/pnML8
REST API Query API
drupal.org/project/
rest_api_query
Services Client
drupal.org/project/
services_client
Feeds (GET only)
drupal.org/project/feeds

24. 4: Approaches

25. Step 5
Now start to code ...

26. Step 5a
Drupal core HTTP
Drupal 7
Demo: NASA ECHO API
Reason for approach: REST but requires XML
Code: http://drupal.org/sandbox/dbassendine/1829568

27. Step 5a
Drupal core HTTP
Pros Cons
Flexible More code (169 lines)
Well structured Encoding / decoding not inc.
request/response
Less structural consistency

29. 5a: ECHO API

34. Demo: ECHO API

35. Step 5b
REST API Query API
Drupal 6 (Open Atrium)
Service: Agile Zen API
Reason for approach: REST and supports JSON
Code: http://drupal.org/sandbox/dbassendine/1828082

36. Step 5b
REST API Query API
Pros Cons
Less code (114L) No XML support
Encoding / decoding inc. Assumptions
More structural
consistency

37. 5b: Agile Zen API

41. Demo: Agile Zen API

42. Creative Commons (CC BY 2.0) by Flickr user Paxson Woelber http://goo.gl/MYPeM

43. Where next?
Triggers Internal Export
Core hooks Logging Views w/
Data module
Rules Job Scheduler
Queue

44. Skills & resources
HTTP protocol http://www.jmarshall.com/easy/http
REST http://rest.elkstein.org
SimpleXML http://goo.gl/IvaKX (php.net)
json_encode/decode http://goo.gl/lKHZ (php.net)
Drupal core HTTP http://goo.gl/pnML8 (d.o)
Drupal REST API Query API drupal.org/project/rest_api_query