Keychain.swift

//
//  Keychain.swift
//  SwiftKeychain
//
//  Created by Chris Hulbert on 14/06/2015.
//  Copyright (c) 2015 Chris Hulbert. All rights reserved.
//

import Foundation
import Security

struct Keychain {
    
    static func deleteItemForKey(key: String) {
        let query = [
            kSecClass as NSString: kSecClassGenericPassword,
            kSecAttrLabel: key,
        ]
        SecItemDelete(query)
    }
    
    static func itemForKey(key: String) -> NSData? {
        let query = [
            kSecClass as NSString: kSecClassGenericPassword,
            kSecAttrLabel: key,
            kSecReturnData: kCFBooleanTrue as CFTypeRef,
        ]
        var unmanagedResult: Unmanaged<AnyObject>?
        // The '&' below converts it to UnsafeMutablePointer<Unmanaged<AnyObject>?>
        let status = SecItemCopyMatching(query, &unmanagedResult)
        // The 'create rule' means the returned result is +1 retained, so we need to balance that.
        let result: AnyObject? = unmanagedResult?.takeRetainedValue()
        return status == errSecSuccess ? result as? NSData : nil;
    }
    
    static func setItem(item: NSData, forKey key: String) {
        self.deleteItemForKey(key) // Remove the item if it exists.
        
        let query = [
            kSecClass as NSString: kSecClassGenericPassword,
            kSecAttrLabel: key,
            kSecValueData: item,
        ]
        SecItemAdd(query, nil);
    }
    
}