2. The Power of a Great API Damian Brady
Microsoft Ignite 2015
2/19/2019 8:28 AM
The Power of a Great API
The case for writing API-first applications
Damian Brady
ARC341B
© 2015 Microsoft Corporation. All rights reserved. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

3. Why is an API a good thing? Implementation Demo
Microsoft Ignite 2015
2/19/2019 8:28 AM
Why is an API a good thing? Implementation Demo
© 2015 Microsoft Corporation. All rights reserved. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

4. I need one button to disable all the machines in an environment❄️

5. Solution One “Sorry, you’re going to have to do it 200 times”
Microsoft Ignite 2015
2/19/2019 8:28 AM
Solution One
“Sorry, you’re going to have to do it 200 times”
© 2015 Microsoft Corporation. All rights reserved. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

6. Solution Two “Sure! We’ll add that!” Microsoft Ignite 2015
2/19/2019 8:28 AM
Solution Two
“Sure! We’ll add that!”
© 2015 Microsoft Corporation. All rights reserved. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

7. Solution Three
“Here’s a script”

8. API Microsoft Ignite 2015 2/19/2019 8:28 AM
© 2015 Microsoft Corporation. All rights reserved. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

10. UNTAPPD

12. API != Public API

13. Implementation

14. UI Business Data Exceptions Microsoft Ignite 2015 2/19/2019 8:28 AM
© 2015 Microsoft Corporation. All rights reserved. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

15. API First Focus on your function Make your UI use your API UI API
Business
Data

16. API Second? Expose your Business layer Refactor or add a layerUI
Expose your Business layer
Refactor or add a layer
Make your UI use your API
API
Data
Business

17. Exposing your API There are plenty of options… but HTTP is easy
Self-hosted endpoints – OWIN, Nancy, ASP.NET 5
PM> Install-Package Microsoft.Owin.SelfHost
PM> Install-Package Nancy.Owin

18. Types of Web APIs HTTP/RPC REST HATEOAS Remote Procedure Call
Method calls over HTTP
Request-response
REST
REpresentational State Transfer
Resource-based URIs
HTTP Verbs
Stateless
HATEOAS
Hypermedia As The Engine Of Application State
REST + links
Self-describing 

19. HTTP/RPC

20. REST

21. HATEOAS
/emojis

22. Be pragmatic

23. What to include? CRUD for Resources + Sensible functions Be pragmatic
POST, GET, PUT, DELETE
/api/customers/1
/api/customers/1/addresses
/api/customers/1?includeDetail=true
/api/customers/1?detailLevel=2
Be pragmatic
Use separate classes

24. Other options OData? GraphQL?
/api/Customers(1)/Orders?$filter='Total gt 10000'&$take=5&$orderby=Total,Date desc
GraphQL?

25. Other things that might hurt
Long-running Tasks Security Versioning Caching Content negotiation

26. Architecture
The Principle of Least Surprise The Pit of Success Be conservative in what you send, liberal in what you accept

27. Architecture Consistent URIs /api/customers/1 /api/order/1
/api/customers?top=5 /api/orders/top?count=5

28. Architecture
Consistent objects
/api/customers/1
/api/customers

29. Let’s make one

30. Why is an API a good thing? Implementation Demo
Microsoft Ignite 2015
2/19/2019 8:28 AM
Why is an API a good thing? Implementation Demo
© 2015 Microsoft Corporation. All rights reserved. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

31. Thankyou
Damian Brady
Octopus Deploy
@damovisa | @octopusdeploy

32. Complete your session evaluation on My Ignite for your chance to win one of many daily prizes.

33. Continue your Ignite learning path
Microsoft Ignite 2015
2/19/2019 8:28 AM
Continue your Ignite learning path
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© 2015 Microsoft Corporation. All rights reserved. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.