This document summarizes a presentation about building backends with Swift. It discusses tools for Swift backend development like Emacs, iTerm, and tmux. It evaluates several Swift frameworks for building backends including Kitura, Perfect, Vapor, and Zewo. It describes implementing the architecture of a test app using concepts from clean architecture. The presentation concludes that Swift code on a Raspberry Pi has some issues but the domain logic can be shared between backend and other code, and building backends with Swift is worth investing in despite current immaturity of the development environment.

1. To Protect &
To Serve
Jorge D. Ortiz-Fuentes
@jdortiz

2. A Canonical
Examples
production
#Swift3Arch

3. Agenda
★ Swift Backend
★ DIY
★ The Test App

4. Swift Backend

5. Disclaimer
Not a backend developer

6. Then, Why?

7. – Gustavo Adolfo Bécquer
“What is poetry? you ask, while fixing
your blue pupil on mine.
What is poetry! And you are asking me?
Poetry... is you.”

8. And you are asking me?
No Refactoring
Compiler Segmentation Fault
Migrations
Moving target
No examples
No reflection&introspection
Xcode

9. Always Look at the Bright
Side of Life
★ Opportunity to learn
★ Linux
★ Backend
★ Swift Package Manager

10. Does it mean that…

11. NO

12. Not ready for
production yet

13. Not ready for
production yet
Some Scenarios

14. Just an
Experiment?

15. Kinda

16. Useful Scenarios
★ Training
★ Prototyping
★ Embedded devices
★ Private servers

17. Server Side Swift is
an IDE
Immature
Development
Environment

18. Swift Package Manager
★ Promising… but not finished
★ Not fully integrated with Xcode
★ May not find a way to satisfy the
dependencies

19. I couldn’t make
libdistpatch
😢

20. I couldn’t make
LLDB work
😢😢😢
Illegal instruction (core dumped)

21. But there is hope
https://swift.org/server-apis/
Saint Chris, Chapter 42 verse FF

22. DIY

23. The Tools
★ Emacs (https://emacsformacosx.com/)
• Tramp (SSH)
• Swift-mode (2.2)
★ iTerm + tmux
★ Google Chrome

24. Frameworks
★ Kitura
★ Perfect
★ Vapor
★ Zewo

25. Kitura
★ Comes with everything and the kitchen
sink
★ Compiles flawlessly
★ Good documentation and tutorials
★ Failed to make libdispatch
for the Raspberry Pi

26. Perfect
★ Also quite complete
★ Excellent documentation & tutorials
★ Doesn’t fully compile in Raspberry Pi 3:
NetTCP.swift & NetTCPSSL.swift (solved)
★ Slack channel
★ Need more time
for the Raspberry Pi

27. Vapor
★ Worked without problems
★ Abundant documentation and tutorials
(vapor.university)
★ Less modular (HTTP server & router
provided by Application class)
for the Raspberry Pi

28. Zewo
★ More modular, from independent pieces
★ Uses libmill/co-routines
★ Failed at compiling OpenSSL (Int size)
★ Really helpful Slack channel (shares members
with Swift-arm channel)
★ Nice todo app example
★ My choice for this experiment
for the Raspberry Pi

29. The Pieces
Server Middleware Controller PersistenceRouter
Views

30. That Sounds
Familiar!

31. Clean Architecture: iOS
App
Delegate
View (VC) Presenter Interactor
Entity
Gateway
Connector

32. The Pieces
Server Middleware Controller PersistenceRouter
Views
Interactor

33. Clean Architecture

34. The Test App

35. Conclusions
★ Swift code in Raspberry Pi has some glitches
★ The domain logic can be in a package:
• Fully tested
• Independent of the rest
★ Use cases can be shared
• No asynchrony
• Some logic may be different
★ Worth the investment

36. Things I Would Like
★ JSON home page / JSONAPI
★ Better (Some) debugging
★ Better support for Raspberry Pi

37. Thank
you!

38. @jdortiz
#Swift3Arch