Slides from NDC Oslo 2014: http://ndcoslo.com/ View a video of the presentation here: http://vimeo.com/97349265 Have you ever received an API or a set of webservices that just weren't good enough? This happens more often than we'd like, and when it happens it's important to know what you can do to make sure your project isn't infected with the lack of quality from third party vendors. I'll talk you through the different stages in your project, highlighting the steps you can take to minimize the risks of integrating your system with another, while making sure it will be maintainable in the future.

1. The integrations we fear
and how we can manage them
Karoline Klever
@karolikl

2. I fear badly written APIs

3. New_GetChanges()
New2_GetChanges()
Old_GetChanges()
Old_New_GetChanges()
Test_GetChanges()

4. I fear heavy payloads

6. I fear uneccessary complexity

7. I fear third party vendors who are
unwilling to cooperate

8. «We’d rather you didn’t use our APIs as they
require about 200 hours of training»
Quote - Head of Account and Sales

9. The phases of integration projects
Setup
Implementation

10. The Setup phase
Find out who to talk to

11. Communicating the hard way
You
Project Manager
Account Manager
Tech guy
Project Manager

12. Reducing the complexity of communication
You Tech guy

13. The Setup phase
Find out who to talk to
Ask for documentation

14. The Setup phase
Find out who to talk to
Ask for documentation
Agree on jurisdiction and specification

15. The Setup phase
Find out who to talk to
Ask for documentation
Agree on jurisdiction and specification
Get access to everything you need

16. The Setup phase
Find out who to talk to
Ask for documentation
Agree on jurisdiction and specification
Get access to everything you need
Demand a test environment

17. Start setting up as soon as possible
Current task Integration Something else
Deadline

18. Start setting up as soon as possible
Current task Integration Something else
Setup Implementation Something else
Deadline
Current task

19. Start setting up as soon as possible
Current task Integration Something else
Setup Implementation Something else
Deadline
Setup
Implementation Something else
Current task
Current task

20. Time consuming communication

21. Time consuming communication
22 emails
15 days

22. The phases of integration projects
Setup
Implementation

23. The Implementation phase
Badly written APIs
Heavy payloads
Uneccessary complexity
Third-party vendors unwilling
to cooperate
Hard to maintain

24. The Implementation phase
Facade pattern
Integration tests
Logging

25. One facade, one API
ProductFacade.cs
Product API

26. One facade, several APIs
ProductInventoryFacade.cs
Product API Inventory API

27. Helper facades
InventoryFacade.cs
Product API ProductFacade.cs

28. Example: Without facades

29. Example: With facades

30. How does the facade look?

31. The Implementation phase
Facade pattern
Integration tests
Logging

32. What do I test?
Internal classes/subsystems
External components
Application Service Layer

33. Example: System under test

34. Example: Integration test

35. The Implementation phase
Facade pattern
Integration tests
Logging

36. Minimal logging

37. Lots of logging

38. Logging with PostSharp

39. OnMethodBoundaryAspect

40. Injecting code

41. Decompiled

42. PostSharp attribute

43. @karolikl
karoline.klever@epinova.no