Cross-platform Swift

Swift is now not only available on all four Apple platforms, but also on Linux — and possibly soon elsewhere as well. Each platform has some peculiarities, but we want to write at least some of our code in a way that works on all of them, e.g. to share a piece of business logic between our iOS application and the server-side. This talk gives an overview on which APIs are available cross-platform and how we can effectively build components that work everywhere.

Transcript

1. CROSS-PLATFORM SWIFT ALTCONF, JUNE 2016 BORIS BÜGLING - @NEONACHO
2. COCOAPODS
3. CONTENTFUL
6. CROSS- PLATFORM SWIFT
7. WHY SWIFT?
8. YA TU SABES
10. !
11. WHICH PLATFORMS CAN WE TARGET?
12. APPLE PLATFORMS ▸ macOS ! ▸ iOS " ▸ watchOS ⌚ ▸ tvOS $ ▸ carOS %
13. FRAMEWORKS SHARED BETWEEN APPLE PLATFORMS CFNetwork.framework CoreData.framework CoreFoundation.framework CoreGraphics.framework CoreLocation.framework CoreText.framework Foundation.framework ImageIO.framework Security.framework
14. THERE'S MORE DEPENDING ON THE SUBSET WE TARGET Accelerate.framework AudioToolbox.framework AudioUnit.framework AVFoundation.framework AVKit.framework CloudKit.framework CoreBluetooth.framework
15. THERE'S MORE DEPENDING ON THE SUBSET WE TARGET CoreImage.framework CoreMedia.framework CoreVideo.framework EventKit.framework GameController.framework GameKit.framework GLKit.framework MapKit.framework
16. THERE'S MORE DEPENDING ON THE SUBSET WE TARGET MediaAccessibility.framework Metal.framework MobileCoreServices.framework SceneKit.framework SpriteKit.framework StoreKit.framework SystemConfiguration.framework
17. UIKIT When only targeting iOS and tvOS
18. NIBS ! If you don't feel like copy-pasting stuff between NIBs ! https://github.com/neonichu/bohne
19. OPEN SOURCE SWIFT ▸ Linux
20. OPEN SOURCE SWIFT ▸ FreeBSD (https://github.com/apple/swift/pull/713) ▸ Windows / Cygwin (https://github.com/apple/swift/pull/1108) ▸ Android (https://github.com/apple/swift/pull/1442)
22. IMPORTING JNI INTO SWIFT module CJavaVM [system] { header "jni.h" link "jvm" export * }
23. CALLING JAVA USING JNI FROM SWIFT import CJavaVM var vm: UnsafeMutablePointer<JavaVM> = nil let env = create_vm(&vm) let jni = env.pointee.pointee let hello_class = jni.FindClass(env, "helloWorld") let main_method = jni.GetStaticMethodID(env, hello_class, "main", "([Ljava/lang/String;)V") jni.CallStaticVoidMethodA(env, hello_class, main_method, [])
24. A REALLY LONG WAY TO GO !
25. FRAMEWORKS SHARED BETWEEN all PLATFORMS Foundation.framework https://github.com/apple/swift-corelibs-foundation
26. FOUNDATION IS INCOMPLETE AND SOMETIMES DIFFERENT FROM OS X #if os(Linux) let index = p.startIndex.distanceTo(p.startIndex.successor()) path = NSString(string: p).substringFromIndex(index) #else path = p.substringFromIndex(p.startIndex.successor()) #endif
27. APPLE'S GOAL ▸ Be compatible with Swift 3.0 ▸ Scheduled to ship by the end of 2016
28. SOME THINGS IN THE STANDARD LIBRARY MIGHT NOT BE AVAILABLE #if _runtime(_ObjC) // Excluded due to use of dynamic casting and Builtin.autorelease, neither // of which correctly work without the ObjC Runtime right now. // See rdar://problem/18801510 [...] public func getVaList(args: [CVarArgType]) -> CVaListPointer {
29. EVEN LIBC IS PROBLEMATIC #if os(Linux) import Glibc #else import Darwin.C #endif
30. E.G. STRUCT MEMBERS CAN BE COMPLETELY DIFFERENT let flags = GLOB_TILDE | GLOB_BRACE | GLOB_MARK if system_glob(cPattern, flags, nil, &gt) == 0 { #if os(Linux) let matchc = gt.gl_pathc #else let matchc = gt.gl_matchc #endif
31. => IT'S COMPLICATED
32. BUT ONLY RIGHT NOW
33. HOW TO SHARE CODE BETWEEN THEM
34. ▸ Shared files ▸ Shared frameworks ▸ Shared packages
35. SHARED FILES
36. BUILD CONFIGURATIONS ▸ os(): OSX, iOS, watchOS, tvOS, Linux ▸ arch(): x86_64, arm, arm64, i386
37. USING BUILD CONFIGURATIONS #if os(OSX) print("Running on OS X") #elseif os(watchOS) print("Running on watchOS") #else print("Running on any platform but OS X and watchOS") #end
38. CAN ALSO BE USED TO DISTINGUISH VERSIONS (SE-0020) #if swift(>=2.2) print("Active!") #else this! code! will! not! parse! or! produce! diagnostics! #endif
39. OR TO SEE IF YOUR CODE IS BEING BUILT BY SWIFTPM #if SWIFT_PACKAGE import Foundation #endif
40. SHARED FRAMEWORKS
41. [XCODE 7 BETA] LINKING DUAL (IPHONEOS AND WATCHOS) FRAMEWORKS WITH SAME PRODUCT NAME CAUSES ARCHIVE TO FAIL http://openradar.appspot.com/22392501
42. SHARED PACKAGES/LIBRARIES ▸ CocoaPods ▸ Carthage ▸ Swift Package Manager
43. COCOAPODS "platforms" : { "osx" : "10.10", "ios": "8.0", "watchos": "2.0", "tvos": "9.0" }
44. IF A POD DOES NOT SUPPORT A CERTAIN PLATFORM ▸ Fork and add it ▸ Submit a PR ▸ For the adventurous ! https://github.com/orta/cocoapods-expert-difficulty
45. COCOAPODS AVOIDS 22392501 ▸ Each duplicated target gets scoped ▸ <.../Build/Debug-iphoneos/Pods-UserTarget/*.framework>
46. CONCHE ▸ Deprecated now, but nice example of what package manifests enable $ conche build Downloading Dependencies -> PathKit 0.5.0 -> Commander 0.5.0 Building Dependencies -> PathKit -> Commander Building Conche Building Entry Points -> conche -> .conche/bin/conche
47. CARTHAGE ▸ Essentially a nicer way to do shared frameworks
48. SWIFT PACKAGE MANAGER ▸ Currently the only way to target Linux ▸ Does not support iOS, watchOS or tvOS, though
49. SWIFT PACKAGE MANAGER ▸ No real platform syntax, but can use build configs: import PackageDescription var package = Package() #if os(Linux) let target = Target(name: "LinuxSources/foo") package.targets.append(target) #endif
50. CURRENT STATUS ▸ Use swiftpm for OS X and Linux ▸ Use CocoaPods for the iOS-ish platforms ▸ Use build configurations to distinguish
51. DEVELOPMENT ENVIRONMENT
52. ▸ Xcode ▸ Xcode + Swift Toolchain ▸ Any editor + swift build
54. SWIFT VERSIONS $ cat .swift-version swift-2.2-SNAPSHOT-2015-12-22-a ▸ Is read by either chswift or swiftenv
55. HOW TO TEST/DEVELOP FOR LINUX?
56. IBM SWIFT SANDBOX ▸ No third party dependencies ▸ Limited to 65535 characters in a source file
57. DOCKER Easiest way on OS X: dlite https://github.com/nlf/dlite/releases $ brew install dlite docker $ sudo dlite install $ docker run -it ubuntu bash
58. DOCKER ▸ A Swift Dockerfile e.g. https://github.com/IBM-MIL/Samples/tree/master/docker- swift $ docker build -t swift ./ $ docker run -it swift /bin/bash $ docker ps # Get 'CONTAINER ID' ▸ or docker pull swiftdocker/swift
59. DOCKER If you don't want to create new containers all the time: $ docker start XXXX $ docker exec -it XXXX /bin/bash $ docker stop XXXX
60. HEROKU ▸ https://github.com/neonichu/swift-buildpack ▸ https://github.com/kylef/heroku-buildpack-swift $ heroku run bash
61. CI
62. TRAVIS CI os: - linux - osx language: generic sudo: required dist: trusty osx_image: xcode7.2 install: - curl -sL https://gist.github.com/kylef/ 5c0475ff02b7c7671d2a/raw/ 621ef9b29bbb852fdfd2e10ed147b321d792c1e4/swiftenv-install.sh | bash script: - . ~/.swiftenv/init
63. PRACTICAL EXAMPLE
64. EMOJI! ! " # $ % & ' ( ) * + , - . / 0 1 2 3 4 5 6 7 8 9 : ; < = > ? @ A B C D E F
65. ELECTRONIC-MOJI import Foundation import Regex extension Character { public var unicodeName: String { let mutableString = NSMutableString(string: "\(self)") CFStringTransform(mutableString, nil, kCFStringTransformToUnicodeName, false) let unicodeName = "\(mutableString)".lowercaseString let regex = Regex(".*\\{(.*)\\}") return regex.match(unicodeName)?.captures.first.flatMap { $0 } ?? unicodeName } } extension CollectionType where Generator.Element == Character { public func findUnicodeName(term: String) -> [Character] { let regex = Regex(".*\(term).*") return self.filter { regex.matches($0.unicodeName) } } }
66. FRANK Frank is a DSL for quickly writing web applications in Swift with type- safe path routing. https://github.com/nestproject/Frank
67. import Emoji import Frank get { _ in return "Hello !\n" } get(*) { (_, name: String) in return (EMOJI.findUnicodeName(name) .map { "\($0)" } .first ?? "¯\\_(ϑ)_/¯") + "\n" }
68. DEMO
69. .build/debug/example [2016-04-26 10:21:09 +0200] [65201] [INFO] Listening at http://0.0.0.0:8000 (65201) [2016-04-26 10:21:09 +0200] [65202] [INFO] Booting worker process with pid: 65202 [worker] GET / - 200 OK [worker] GET /glasses - 200 OK [worker] GET /nerd - 200 OK $ curl http://localhost:8000 Hello ! $ curl http://localhost:8000/glasses " $ curl http://localhost:8000/nerd #
70. EMOJI SEARCH KEYBOARD https://github.com/neonichu/emoji-search-keyboard
71. CLI TOOL $ electronic-moji bird !
72. CONCLUSION ▸ It's complicated :) ▸ Still a lot of code can be shared ▸ Swift 3.0 will help a lot
73. THANK YOU!
74. REFERENCES ▸ https://swift.org ▸ https://github.com/neonichu/freedom ▸ https://github.com/kylef/swiftenv ▸ https://github.com/nestproject/Frank ▸ https://speakerdeck.com/jpsim/practical-cross-platform-swift ▸ https://speakerdeck.com/kylef/end-to-end-building-a-web-
75. “Experienced engineer examines comments in a legacy module” — => http://classicprogrammerpaintings.com
76. @NeoNacho boris@contentful.com http://buegling.com/talks