为什么我不能在Swift应用程序的钥匙串中放入（通过alamofire呼叫）令牌？

Question

I have a webservice that returns me some data like name , login and auth_token . So far I was saving name and login in the NSUserDefaults. Now I want to store safely also auth_token , so I've decided to put it in the keychain. For that purpose I've decided to use https://github.com/matthewpalmer/Locksmith this plugin.

So far my code looked like this:

Alamofire.request(.POST, "\(serverURL)/authorization", parameters: params)
    .validate()
    .response { (request, response, data, error) in
        if(error != nil){
            print("error = \(error)") 
        }else{

            let username = json["name"]
            let login = json["login"]
            let auth_token = json["auth_token"]

            let defaults =  NSUserDefaults.standardUserDefaults()

            defaults.setObject(login, forKey: "login")
            defaults.setObject(username, forKey: "username")

            defaults.synchronize() 

            let sb = UIStoryboard(name: "Main", bundle: nil)
            if let tabBarVC = sb.instantiateViewControllerWithIdentifier("TabController") as? TabController {
                self.window!.rootViewController = tabBarVC
            }

        }
}

but when I added this line:

 try Locksmith.saveData(["auth_token": json["auth_token"]], forUserAccount: "my_auth_token") 

right after this:

 let defaults =  NSUserDefaults.standardUserDefaults()

then I'm getting error on Alamofire.request saying:

Cannot call value of non-function type 'NSHTTPURLResponse?'

So my question is - how can I save my auth_token that comes from the webservice in the keychain?

Answer 1

What you're running into is a type mismatch, and the unfortunate fact that the AlamoFire Request class has both a function called response , and a property called response (of type NSHTTPURLResponse? , look familiar =))

In your code you're calling try , which requires the enclosing closure/function to be marked throws , or you have to wrap your code in a do-catch

So what the swift compiler is doing is inferring that the closure you are writing has throws as part of its definition. This obviously doesn't match the definition of the closure that should be passed to the func response , so it tries the other response it can find, the property. Then it just completely fails because you cannot try to 'call' an optional type.

You should add a do-catch inside your closure to handle the possible errors that Locksmith may throw.

Edit: In response to your comment. You just need to wrap that call in a do catch to properly handle errors. See https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/ErrorHandling.html for details on Swifts error handling model.

As for which error to catch, just glancing through the Locksmith API, it can throw errors that it receives from the Keychain API. Luckily they have defined the errors they throw here: https://github.com/matthewpalmer/Locksmith/blob/master/Source/LocksmithError.swift

As an example of what to write, it would just be something like this

Alamofire.request(.POST, "\(serverURL)/authorization", parameters: params)
    .validate()
    .response { (request, response, data, error) in
        if(error != nil){
            print("error = \(error)") 
        }else{

            let username = json["name"]
            let login = json["login"]
            let auth_token = json["auth_token"]

            let defaults =  NSUserDefaults.standardUserDefaults()
            do {
                try Locksmith.saveData(["auth_token": json["auth_token"]], forUserAccount: "my_auth_token")
            } catch {
                // Handle the error, however you best see fit
                print("Error trying to save to keychain \(error)")
            }

            defaults.setObject(login, forKey: "login")
            defaults.setObject(username, forKey: "username")

            defaults.synchronize() 

            let sb = UIStoryboard(name: "Main", bundle: nil)
            if let tabBarVC = sb.instantiateViewControllerWithIdentifier("TabController") as? TabController {
                self.window!.rootViewController = tabBarVC
            }

        }
}