Rake task to easily package iOS static library into .framework bundle

Rakefile

# This assumes you have placed your public header files in the `Headers`
# directory in your output directory. You can satisfy that easily by creating a
# "Copy Files" build phase. See
# http://image.bayimg.com/9cf4804007f7a7b59505de345ad2bbc388499475.jpg

# Usage:
#
# 1. Change `PROJECT_NAME` below. E.g. if you have `Calculator.xcodeproj`, change it to `"Calculator"`
# 2. Put this beside your `.xcodeproj` file, then just run `rake`

task :default => :build

SDKS         = %w(iphonesimulator iphoneos).freeze
CONFIGS      = %w(Debug Release).freeze
BUILD_DIR    = "build".freeze
PROJECT_NAME = "MyCoolFramework".freeze

def run(command)
  puts "> #{command}"
  system(command)
  fail "Command \`#{command}\` failed with exit status #{$?}" if !$?.success?
end

task :build do
  CONFIGS.each do |config|
    fat_lib = File.join(BUILD_DIR, config, "lib#{PROJECT_NAME}.a")
    FileUtils.mkdir_p(File.join(BUILD_DIR, config))

    SDKS.each do |sdk|
      run "xcodebuild -sdk #{sdk} -configuration #{config}"
    end

    inputs = SDKS.map do |sdk|
      File.join(BUILD_DIR, "#{config}-#{sdk}", "lib#{PROJECT_NAME}.a")
    end

    run "lipo -create #{inputs.join(' ')} -output #{fat_lib}"
  end

  CONFIGS.product(SDKS).each do |config, sdk|
    fat_lib = File.join(BUILD_DIR, config, "lib#{PROJECT_NAME}.a")

    headers_dir = File.join(BUILD_DIR, "#{config}-#{sdk}", "Headers")
    framework_dir = File.join(BUILD_DIR, config, "#{PROJECT_NAME}.framework")
    version_a_dir = File.join(framework_dir, "Versions", "A")

    FileUtils.mkdir_p(version_a_dir)
    FileUtils.cp_r(headers_dir, version_a_dir, :preserve => true)
    FileUtils.cp(fat_lib, File.join(version_a_dir, PROJECT_NAME))

    FileUtils.rm_f(File.join(framework_dir, "Versions", "Current"))
    FileUtils.ln_sf("A", File.join(framework_dir, "Versions", "Current"))

    FileUtils.rm_f(File.join(framework_dir, "Headers"))
    FileUtils.rm_f(File.join(framework_dir, PROJECT_NAME))

    FileUtils.ln_sf(File.join("Versions", "Current", "Headers"), framework_dir)
    FileUtils.ln_sf(File.join("Versions", "Current", PROJECT_NAME), framework_dir)
  end
end