Superb

Pluggable HTTP authentication for Swift.

Advantages

• Safe, secure token storage in the iOS Keychain.
• Automatic handling of 401 responses and reauthentication.
• Scales to handle many concurrent requests in a thread-safe way.
• Stays out of your way until you need it with a simple, minimal API.
• Promotes Apple’s Authentication Guidelines by “delaying sign-in as long as possible”.
• Supports adapters for any number of authentication providers.
• Extensible without requiring any source modifications or pull requests.

Caveats

• Opinionated about user experience.

Usage

Example: GitHub OAuth Authentication

When you register the app with your OAuth provider, you will give a redirect
URI. This URI must use a URL scheme that is registered for your app in your
app’s Info.plist.

Superb allows your app to support multiple authentication providers via a
registration mechanism. iOS apps have a single entrypoint for URLs, so Superb
searches through the registered providers to find the correct one to handle the
redirect URL.

// GitHub+Providers.swift

import Superb
import SuperbGitHub

extension GitHubOAuthProvider {
  static var shared: GitHubOAuthProvider {
    // Register a provider to handle callback URLs
    return Superb.register(
      GitHubOAuthProvider(
        clientId: "<your client id>",
        clientSecret: "<your client secret>",
        redirectURI: URL(string: "<your chosen redirect URI>")!
      )
    )
  }
}

// AppDelegate.swift

@UIApplicationMain
final class AppDelegate: UIResponder, UIApplicationDelegate {
  // ...

  func application(_ app: UIApplication, open url: URL, options: [UIApplicationOpenURLOptionsKey: Any]) -> Bool {
    // Pass the URL and options off to Superb.
    return Superb.handleAuthenticationRedirect(url, options: options)
  }
}

Then, in our API client, we can use RequestAuthorizer to fence the code that
must be run with authentication, using RequestAuthorizer.performAuthorized().

// GitHubAPIClient.swift

struct GitHubAPIClient {
  static let oauthClient = GitHubAPIClient(
    requestAuthorizer: RequestAuthorizer(
      authorizationProvider: GitHubOAuthProvider.shared
    )
  )

  private let authorizer: RequestAuthorizerProtocol

  init(requestAuthorizer: RequestAuthorizerProtocol) {
    authorizer = requestAuthorizer
  }

  // An authorized request to get the current user's profile.
  func getProfile(completionHandler: @escaping (Result<Profile, SuperbError>) -> Void) {
    let request = URLRequest(url: URL(string: "https://api.github.com/user")!)

    authorizer.performAuthorized(request) { result in
      switch result {
      case let .success(data, _):
        let profile = parseProfile(from: data)
        completionHandler(.success(profile))

      case let .failure(error):
        completionHandler(.failure(error))
      }
    }
  }

  // An unauthorized request.
  func getZen(completionHandler: @escaping (Result<String, SuperbError>) -> Void) {
    let request = URLRequest(url: URL(string: "https://api.github.com/zen")!)

    URLSession.shared.dataTask(with: request) { data, _, error in
      let result = parseZen(data, error)
      completionHandler(result)
    }.resume()
  }
}

// later
let api = GitHubAPIClient.oauthClient

api.getProfile { result in
  // ...
}

List of Authentication Providers

• GitHub

Installation

Carthage

Add the following to your Cartfile:

github "thoughtbot/Superb" ~> 0.2

Then run carthage update.

Follow the current instructions in Carthage’s README
for up to date installation instructions.

You will need to embed both Superb.framework and Result.framework in your
application.

CocoaPods

Add the following to your Podfile:

pod "Superb", "~> 0.2.0"

You will also need to make sure you’re opting into using frameworks:

use_frameworks!

Then run pod install.

Troubleshooting

Authentication always fails when using OAuth

You forgot to call Superb.register.

If you do not call Superb.register then your authentication provider will not
have a chance to receive callback URLs.

Contributing

See the CONTRIBUTING document. Thank you, contributors!

License

Superb is Copyright © 2017 thoughtbot, inc. It is free software, and may be
redistributed under the terms specified in the LICENSE file.

About

Superb is maintained and funded by thoughtbot, inc. The names and logos for
thoughtbot are trademarks of thoughtbot, inc.

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