AlamofireでBasic認証を事前に(全体に)適用する

通常は公式にあるとおり、リクエストごとに認証(authenticate)をいれてリクエストする方法があります。

let user = "user"
let password = "password"

Alamofire.request(.GET, "https://httpbin.org/basic-auth/\(user)/\(password)")
         .authenticate(user: user, password: password)
         .response {(request, response, _, error) in
             println(response)
         }

ただ毎回同じ場合、１箇所に設定しておきたいですよね。
下記のようにAppDelegateに設定可能です。

AppDelegate.swift

    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        // Override point for customization after application launch.

        let user = "user"
        let password = "password"

        let plainString = "\(user):\(password)" as NSString
        let plainData = plainString.dataUsingEncoding(NSUTF8StringEncoding)
        let base64String = plainData?.base64EncodedStringWithOptions(NSDataBase64EncodingOptions.allZeros)

        Alamofire.Manager.sharedInstance.session.configuration.HTTPAdditionalHeaders = ["Authorization": "Basic " + base64String!]

//以下省略

参考
https://github.com/Alamofire/Alamofire/issues/32