Wie für viele andere Plattformen, so ist auch für XING die Öffnung der Rechenzentrumsgrenzen mit Hilfe von externen APIs, z.B. zur Partnerintegration, ein wichtiges Thema. In diesem Vortrag werfen wir einen Blick auf die Interna der (API-)Entwicklung bei XING: Architektur der Plattform, Historie der verschiedenen APIs, Entwicklungsprozesse, best practices beim API-Design, enge Zusammenarbeit mit einzelnen Consumern sowie (rechtliche) Herausforderungen bei der Datenweitergabe via API.

2. API-Entwicklung
bei XING
Mark Schmidt

3. XING?
Bestehende APIs
Schritte zu einer guten API

4. ?

6. Technologie-Department

7. rdware
Ha

8. Software

9. Bestehende APIs

10. Interne APIs:

11. YAML HTTP API / Perl Backend

12. Gearman

13. gemeinsam genutzte Datenbanken

14. SSH

15. FTP

16. AMQP / RabbitMQ

17. REST-APIs

19. Externe APIs:

20. XWS 1

21. XWS+

22. SOAP-Schnittstelle für Payment

23. (+ kleine Insellösungen)

24. das (externe) API-Team

25. Schritte zu einer guten API
Schritte zu einer
guten API

26. Warum ist API-Design wichtig?

27. Gute API?
→ J.Bloch, How to Design a Good API and Why it Matters, 2006

28. Einfach zu erlernen
→ J.Bloch, How to Design a Good API and Why it Matters, 2006

29. Einfach zu benutzen, auch
ohne Dokumentation
→ J.Bloch, How to Design a Good API and Why it Matters, 2006

30. Lässt sich nur schwer falsch
benutzen
→ J.Bloch, How to Design a Good API and Why it Matters, 2006

31. Client-Code ist gut les- und
wartbar
→ J.Bloch, How to Design a Good API and Why it Matters, 2006

32. Ausreichend mächtig
→ J.Bloch, How to Design a Good API and Why it Matters, 2006

33. Einfach zu erweitern
→ J.Bloch, How to Design a Good API and Why it Matters, 2006

34. Geeignet für die Zielgruppe
→ J.Bloch, How to Design a Good API and Why it Matters, 2006

35. Probleme... Fragen... Lösungen?

36. REST!

37. REpresentationalStateTransfer!
→ R. Fielding, Architectural Styles and the Design of Network-based Software Architectures , 2000

38. Response-Format

39. GET https://api.xing.com/v1/users/123456_abcdef/contacts/upcoming_birthdays?limit=3&offset=0
{
"upcoming_birthdays": {
"total": 34,
"items": [{
"user": {"id": "52313245_52f7g0"},
"day": 20,
"month": 10,
"year": 1980
}, {
"user": {"id": "78787878_12h4g2"},
"day": 22,
"month": 10,
"year": 1965
}, {
"user": {"id": "3453245_h190cx"},
"day": 23,
"month": 10,
"year": null
}]
}
}

40. Status-Codes

41. 200, 201, 204

42. 400, 401, 403, 404, 405

43. (500, ) 503

44. ∀ > 400 : {JSON,XML}

45. {
"error_name": "INVALID_OAUTH_TOKEN",
"message": "Invalid OAuth token",
"revoke_reason": "PASSWORD_CHANGED"
}

46. API-Domäne != Produkt-Domäne

47. intern: Module
namespace
/rest/newsfeed/activitystream/:user_id
REST
API
namespace Module
Resources
extern:
/v1/users/:user_id/network_feed

48. Versionierung

49. GET api.xing.com/users/123?version=1
vs.
GET api.xing.com/v1/users/123
vs.
GET api.xing.com/users/123
Accept: application/vnd.xing.user-v1+json

50. Hinzufügen neuer Calls? Kein
Problem, aber...

51. Call-Lifecycle

52. Eingabe
⤻
Ausgabe

53. KISS

54. module WebService
class CommentsController < WebService::ServiceController
add_call :name => 'Get comments of an activity',
:description => "Returns a list of all comments which have been made for an activity.",
:status => :experimental,
:experimental_since => '2011-05-02',
:action => 'index',
:permission => :activity_stream,
:required_parameters => {
"activity_id" => "Activity ID"
},
:optional_parameters => {
'limit' => "How many comments to return. Must be a positive number. Default: 10",
"offset" => "Offset. Must be a positive number. Default: 0",
"user_fields" => "Comma separated list of user attributes to return..."
},
:returns => {
:success => {:code => 200, :message => 'The call was completed successfully'},
:invalid_parameters => {:code => 403, :message => '...', :error => 'INVALID_PARAMETERS'},
:access_denied => {:code => 403, :message => '...', :error => 'ACCESS_DENIED'},
:activity_not_found => {:code => 404, :message => '...', :error => 'ACTIVITY_NOT_FOUND'}
},
:response_example => "..."
end
end

55. module WebService::Handlers
class CommentsHandler < WebService::Handlers::Base
include WebService::Handlers::Helpers
def index(params)
activity = find_activity!(params[:activity_id], :rid => User.current.id)
limit, offset = pagination_params!(params[:limit], params[:offset])
result = { :comments => [] }
if activity[:comments].any? && activity[:comments].size > offset
user_fields = filter_user_fields(params[:user_fields])
result[:comments] = ActivityStream::Comment.build(activity[:comments],
:user_fields => user_fields)[offset, limit]
end
result
rescue ResourceNotFoundError
:activity_not_found
rescue InvalidParameterError => e
[:invalid_parameters, {:message => e.message}]
rescue AccessDeniedError
:access_denied
end
end
end

56. ActionController::Routing::Routes.draw do |map|
map.namespace(:web_service, :path_prefix => 'v1') do |v1|
v1.resources :activities do |activities|
activities.resources :comments, :only => [:index]
end
end
end

57. Oauth für Partnerintegrationen?

58. Wie geht‘s weiter?

59. Noch 2 Punkte in eigener Sache:

60. api@xing.com

61. Product Owner
Ruby Developer
Perl Developer
Quality Assurance Manager
Frontend Developer
Interaction Designer
...
XING sucht
neue Kollegen!