How (not) to write an iOS SDK

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How (not) to write an iOS SDK Conrad Kramer

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We consume a lot of SDKs in Workﬂow We also have to roll our own SDKs for Workﬂow

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Don't make assumptions

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Language

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Write in Objective-C Use nullability and generics Don't expose C++

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Write a Swift wrapper All versions of Swift

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Build System

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Have an Xcode project Dynamic and static libraries Support Carthage

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Have a podspec

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Support Swift Package Manager Package.swift

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Environment

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Make ﬁle paths conﬁgurable App groups are a thing Have reasonable defaults

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Don't rely on UIApplication If you must, mark APIs with NS_EXTENSION_UNAVAILABLE If you need background time, use NSProcessInfo

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Handle inter-process coordination This is hard

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WFNotiﬁcationCenter

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Support all platforms watchOS, tvOS iOS, macOS carOS

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Deployment Target

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Dependencies Avoid them

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Document your API High level overview Method speciﬁc documentation

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Tests Merge with conﬁdence

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Performance Document expensive API calls Use Grand Central Dispatch queues

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Performance Monitor memory utilization +load, objc_copyClassList, UIWebView, CGBitmapContext!