XCFramework

My need was to use GoogleSignIn with the Swift Package Manager. And more specifically, I wanted to create a Swift package which itself depends on GoogleSignIn.

GoogleSignIn is designed to be used either directly in an Xcode project -- i.e., by dragging the Google Sign In files into the project, or through the Cocoapods dependency manager. I have been unable to find any Google-provided means to use GoogleSignIn as a dependency for a Swift package, with its own Package.swift manifest file.

It appears the way to achieve this goal is to convert GoogleSignIn to an XCFramework. I am using the resulting XCFramework in my iOSGoogle package which provides Google Sign In services for SyncServerII on iOS.

This effort started its life as SMGoogleSignIn, which was targeted at Cocoapods. The doc section at the bottom titled SMGoogleSignIn gives that history.

TL;DR

If you just want to use this XCFramework and skip all the reading, add this target into your Package.swift.

This is for Google Sign In version 5.0.2:

.binaryTarget(
    name: "GSignIn",
    url: "https://github.com/SyncServerII/GSignIn/raw/main/XCFrameworks/GSignIn-5.0.2.xcframework.zip",
    checksum: "b2b468ca98bcbe7d771726cd2a1ea6f9bee785957af8c9f4c75aa10e5c337a52"
),

Note that you must be using at least Swift 5.3 in your Package.swift. E.g., have this at the top of the Package.swift:

// swift-tools-version:5.3

Generating the checksum used above

You need to run the swift package compute-checksum command (see this reference from a directory containing a Package.swift file (see this reference). This is why the FakePackage directory is present. Generate a zip file with the XCFramework, copy or move it into the FakePackage directory and from the root directory (containing this README.md) run:

swift package --package-path FakeExample compute-checksum FakeExample/GSignIn.xcframework.zip

GSignIn

I have renamed this repo GSignIn to distinguish it from SMGoogleSignIn (for Cocoapods) and GoogleSignIn-- Google's library.

Creating the XCFramework

My creation of the XCFramework is adapted from https://medium.com/@er.mayursharma14/how-to-create-xcframework-855817f854cf

Set some variables in a terminal window

In a terminal window, within the GSignIn repo folder, run:

FRAMEWORK_NAME=GSignIn
SIMULATOR_ARCHIVE_PATH=GSignIn.Simulator.xcarchive
IOS_DEVICE_ARCHIVE_PATH=GSignIn.iOS.xcarchive

Create frameworks for GSignIn for iOS and the iOS Simulator

Next, in the same terminal window, run:

xcodebuild archive -scheme ${FRAMEWORK_NAME} -destination="iOS Simulator" -archivePath "${SIMULATOR_ARCHIVE_PATH}" -sdk iphonesimulator SKIP_INSTALL=NO SUPPORTS_MACCATALYST=NO BUILD_LIBRARIES_FOR_DISTRIBUTION=YES

and then run:

xcodebuild archive -scheme ${FRAMEWORK_NAME} -destination="iOS" -archivePath "${IOS_DEVICE_ARCHIVE_PATH}" -sdk iphoneos SKIP_INSTALL=NO SUPPORTS_MACCATALYST=NO BUILD_LIBRARIES_FOR_DISTRIBUTION=YES

Make sure that both of those run without errors.

Create the XCFramework for use in the Swift Package Manager

Next, in the same terminal window, run:

xcodebuild -create-xcframework -framework ${SIMULATOR_ARCHIVE_PATH}/Products/Library/Frameworks/${FRAMEWORK_NAME}.framework -framework ${IOS_DEVICE_ARCHIVE_PATH}/Products/Library/Frameworks/${FRAMEWORK_NAME}.framework -output "${FRAMEWORK_NAME}".xcframework

Cleanup

Finally, run this in the same terminal window:

rm -rf "${SIMULATOR_ARCHIVE_PATH}"
rm -rf "${IOS_DEVICE_ARCHIVE_PATH}"

Using the XCFramework

You can now now copy the folder GSignIn.xcframework in to your Swift package. To reference it you need to add something like the following in your Package.swift file:

.binaryTarget(
    name: "GSignIn",
    path: "Frameworks/GSignIn.xcframework"
),

I had put the XCFramework into a folder called Frameworks. See also the usage in iOSGoogle.

In your code, you then add:

import GSignIn

and you can use Google's Sign In library like you normally would.

Known current issues

I am currently unable to access the embedded .bundle that Google provides in their Google Sign In. Specifically, their GIDSignInButton when rendered in iOS doesn't have graphic assets. In iOSGoogle I work around this by creating my own button. See GoogleSignInOutButton in that package.

Development problem 1

I was having errors on 12/15/20 when building for simulator; see https://stackoverflow.com/questions/63607158. I had to make some changes to the GSignIn.xcodeproj used for this-- by adding settings into Excluded Architecture.

Development problem 2

I ran into this problem building on the simulator (not an actual device) when integrating the xcframework into my iOSGoogle package:

CodeSign /Users/chris/Library/Developer/Xcode/DerivedData/iOSGoogle-cjpcgggznffoaybhhrtzqzkxayww/Build/Products/Debug-iphonesimulator/iOSGoogle_iOSGoogle.bundle (in target 'iOSGoogle_iOSGoogle' from project 'iOSGoogle')
    cd /Users/chris/Desktop/NewSyncServer/iOSGoogle
    export CODESIGN_ALLOCATE\=/Users/chris/Desktop/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/codesign_allocate
    
Signing Identity:     "-"

    /usr/bin/codesign --force --sign - --timestamp\=none /Users/chris/Library/Developer/Xcode/DerivedData/iOSGoogle-cjpcgggznffoaybhhrtzqzkxayww/Build/Products/Debug-iphonesimulator/iOSGoogle_iOSGoogle.bundle

/Users/chris/Library/Developer/Xcode/DerivedData/iOSGoogle-cjpcgggznffoaybhhrtzqzkxayww/Build/Products/Debug-iphonesimulator/iOSGoogle_iOSGoogle.bundle: bundle format unrecognized, invalid, or unsuitable
Command CodeSign failed with a nonzero exit code

Two references on this issue: https://stackoverflow.com/questions/58195914/xcode-11-command-codesign-failed-with-a-nonzero-exit-code

https://stackoverflow.com/questions/52421999

The solution: Don't give a directory in your Swift package the name Resources. Very odd.

Development problem 3

As I wrote up at https://stackoverflow.com/questions/65469685 on 12/28/20 and 12/29/20, I had been getting linker warnings and errors. That solutions I wrote up on the same SO post on 1/1/21.

SMGoogleSignIn

(For reference, from SMGoogleSignIn).

Since SyncServer is a framework, I wanted a means to provide Google Sign In for iOS clients so that they didn't have to explicitly import GoogleSignIn. That is, I wanted to do this just like the way I'm doing this with Facebook and Dropbox: Just select the subspec in your Cocoapods Podfile and you are off to the races. However, Google Sign In doesn't make this easy-- at this time (early June 2018), Google provides static libraries. Well, you say, Cocoapods can now support static vendored_libraries. Yea! Hmmm. I tried doing this. I get a gnarly error: "unsealed contents present in the bundle root" from Xcode. I wasn't able to make progress with that issue.

Instead, I took the route of converting the Google Sign In framework to a dynamic framework using these instructions

This repo is the result of that process.

Build process: Build from `GoogleSignIn.xcodeproj`

GoogleSignIn.xcodeproj is not part of the Cocoapod, but rather enables you to build the dynamic GoogleSignIn.framework

See https://stackoverflow.com/questions/5010062/xcodebuild-simulator-or-device and https://stackoverflow.com/questions/29634466/how-to-export-fat-cocoa-touch-framework-for-simulator-and-device

To update the version of the Google SDK and update the project

Download the most recent version of the Google SDK from https://developers.google.com/identity/sign-in/ios/sdk/
In the downloaded folder, you should see three main file/folders: GoogleSignIn.bundle, GoogleSignIn.framework, GoogleSignInDependencies.framework
Rename the downloaded folder to "google_signin_sdk" (it should have been named something like "google_signin_sdk_4_4_0").
Replace that named folder in the repo with the new "google_signin_sdk".
I had to rename the file within the GoogleSignIn.framework/Headers/GoogleSignIn.h obtained from Google to GoogleSignIn.framework/Headers/GoogleSignInAll.h to work around a naming conflict.
Note that the names of the header files in google_signin_sdk/GoogleSignIn.framework/Headers might have changed, and you might have to adjust these in GoogleSignIn.xcodeproj
Make sure the headers for the library are all public:
Read through the section Link dependent frameworks to your Xcode project in https://developers.google.com/identity/sign-in/ios/sdk/ to see if you need to add other (more) libraries. (I ran into some odd looking link issues when I didn't remember this).

xcodebuild -target GoogleSignIn -configuration Release -sdk iphonesimulator ONLY_ACTIVE_ARCH=NO BUILD_DIR="build" BUILD_ROOT="build" clean build

The following builds for arm64 and armv7

I had to add -fembed-bitcode to OTHER_CFLAGS in the project build settings because I got "ld: bitcode bundle could not be generated" when I tried to build SharedImages. I also added this to the linker flags.

And I'm now making release builds because that seems to be the way to generate bitcode. See https://stackoverflow.com/questions/31233395/ios-library-to-bitcode

xcodebuild -target GoogleSignIn -configuration Release -sdk iphoneos ONLY_ACTIVE_ARCH=NO BUILD_DIR="build" BUILD_ROOT="build" clean build

Copy the framework structure (from iphoneos build) to the universal folder-- the lipo step only builds the executable, not the framework structure. Note that trash is just a command to move to the directory to the Trash folder.

trash Framework/GoogleSignIn.framework

cp -R "build/Release-iphoneos/GoogleSignIn.framework" "Framework/GoogleSignIn.framework"

Note we're replacing the non-fat binary in the step above with the fat binary.

lipo -create -output "Framework/GoogleSignIn.framework/GoogleSignIn" "build/Release-iphonesimulator/GoogleSignIn.framework/GoogleSignIn" "build/Release-iphoneos/GoogleSignIn.framework/GoogleSignIn"

Note that the name of the resulting framework must be GoogleSignIn-- i.e., it must match the name of the .bundle file-- or the graphics and text will not load into the Google Sign In button.

Podspec Note

One of my struggles in developing this dynamic version of Google's framework was getting the GoogleSignIn.bundle to be properly accessed by the framework. The problem was that I was getting the GIDGoogleSignIn button appearing on the UI, but the graphics and text didn't appear-- and these come from the .bundle file. To deal with this, I have derived the form of the podspec I'm using here from Google's-- https://github.com/CocoaPods/Specs/blob/master/Specs/d/4/0/GoogleSignIn/4.1.2/GoogleSignIn.podspec.json (see also "See Podspec" link in https://cocoapods.org/pods/GoogleSignIn). See also https://stackoverflow.com/questions/50750862/using-google-sign-in-frameworks-in-a-cocoapod-subspec

cleanbit/GSignIn