motion-authentication

motion-authentication aims to provide a simple, standardized authentication helper for common authentication strategies.

Currently, this library only supports iOS, but could easily support other platforms. Please submit an issue (or PR :D) for the platform you would like to support.

Need authorization? Use motion-authorization!

Installation

Add this line to your application's Gemfile, then run bundle install:

gem 'motion-authentication', '~> 2.0'

Next, run rake pod:install to install the CocoaPod dependencies.

Usage

Start by subclassing Motion::Authentication to create your own Auth class. Specify your authentication strategy and your sign in URL:

class Auth < Motion::Authentication
  strategy DeviseCookieAuth
  sign_in_url "https://example.com/api/v1/users/sign_in"
end

Available strategies:

• DeviseCookieAuth - This strategy supports the default way of authenticating with Devise, just as if you were submitting the sign in form using a web browser. It works by making an initial request to fetch the authenticity token, then submits the email and password, then stores the resulting cookie for authenticating future requests. If your user model has a different name (i.e. AdminUser), pass along the namespace option (i.e. namespace: 'admin_user') when calling sign_in. Otherwise, namespace defaults to :user.

• DeviseSimpleTokenAuth - This authentication strategy is based on José Valim's example gist and is compatible with the simple_token_authentication gem, and the Ember Simple Auth Devise adapter.

This strategy takes email and password, makes a POST request to the sign_in_url, and expects the response to include email and token keys in the JSON response object.

• DeviseTokenAuth - This authentication strategy is compatible with the devise_token_auth gem.

Signing up: this strategy takes email, password and password_confirmation, makes a POST request to the sign_up_url, and expects the response to include uid, access-token and client keys in the response object headers.

Signing in: this strategy takes email and password, makes a POST request to the sign_in_url, and expects the response to include uid, access-token and client keys in the response object headers.

.sign_in

Using your Auth class, call .sign_in and pass a hash of credentials:

Auth.sign_in(email: email, password: password) do |result|
  if result.success?
    # authentication successful!
  else
    app.alert "Invalid email or password"
  end
end

.signed_in?

You can check if an auth token has previously been stored by using signed_in?. For example, in your App Delegate, you might want to open your sign in screen when the app is opened:

def on_load(options)
  if Auth.signed_in?
    open DashboardScreen
  else
    open SignInScreen
  end
end

.authorization_header

After signing in, assuming you are using one of the token auth strategies, you will want to configure your API client to use your auth token in your API requests in an authorization header. Call .authorization_header to return the header value specific to the strategy that you are using. Two common places would be upon sign in, and when your app is launched.

# app_delegate.rb
def on_load(options)
  if Auth.signed_in?
    MyApiClient.update_auth_header(Auth.authorization_header)
    # ...
  end
end

# sign_in_screen.rb
def on_load(options)
  Auth.sign_in(data) do |result|
    if result.success?
      MyApiClient.update_auth_header(Auth.authorization_header)
      # ...
    end
  end
end

Note on DeviseTokenAuthGem strategy

The devise_token_auth gem requires all authenticated API calls to include the keys uid, access-token and client in the HTTP headers. Calling .authorization_header will return a hash with the proper key/value pairs. To include these as headers in all calls we recommend setting up your API client as follows:

ApiClient.update_authorization_header(Auth.authorization_header)

class ApiClient
  class << self
    def client
      @client ||= AFMotion::SessionClient.build("http://localhost:3000/") do
        response_serializer :json
        header "Content-Type", "application/json"
      end
    end

    def update_authorization_header(auth_headers_hash)
      auth_headers_hash.each do |key, value|
        client.headers[key] = value
      end
    end
  end
end

.sign_out

At some point, you're going to need to sign out. This method will clear the stored auth token, but also allows you to pass a block to be called after the token has been cleared.

Auth.sign_out do
  open HomeScreen
end

.current_user

motion-authentication provides a current_user attribute. It has no effect on authentication, so you can do whatever you want with it.

Auth.sign_in(data) do |result|
  if result.success?
    Auth.current_user = User.new(result.object)
  end
end

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request