Swift で Bundle Seed Id(App Identifer)を取得する

Keychain の AccessGroup などで利用する Bundle Seed Id(App Identifer) を取得する方法です。

import UIKit
import Security

extension UIApplication {

    class var bundleSeedId: String {
        struct Static {
            static var token : dispatch_once_t = 0
            static var identifier: String!
        }

        dispatch_once(&Static.token) {

            let query: NSDictionary = NSDictionary(objects: [kSecClassGenericPassword, "Bundle Seed ID", kCFBooleanTrue], forKeys: [kSecClass, kSecAttrAccount, kSecReturnAttributes])

            var result: Unmanaged<AnyObject>?
            var status: OSStatus = SecItemCopyMatching(query as CFDictionaryRef, &result)

            if status == errSecItemNotFound {
                status = SecItemAdd(query as CFDictionaryRef, &result);
            }

            if status == errSecSuccess {
                if let op = result?.toOpaque() {
                    let resultDict: NSDictionary = Unmanaged<NSDictionary>.fromOpaque(op).takeUnretainedValue()

                    if let accessGroup = resultDict[kSecAttrAccessGroup as NSString] as? NSString {
                        let components = accessGroup.componentsSeparatedByString(".")
                        Static.identifier = components[0] as? String
                    }
                }
            }
        }

        return Static.identifier
    }
}