MultiAuth

MultiAuth is a library that standardizes multi-provider authentication for web applications. Currently supported providers:

• Github.com
• Facebook.com
• Vk.com
• Google.com, setup google
• Twitter.com

Installation

Add this to your application's shard.yml:

dependencies:
  multi_auth:
    github: msa7/multi_auth

Usage

MultiAuth public interface

  require "multi_auth"

  MultiAuth.config("github", ENV['ID'], ENV['SECRET']) # configuration

  multi_auth = MultiAuth.make(provider, redirect_uri) # initialize engine
  multi_auth.authorize_uri  # URL to provider authentication dialog

  # on http callback, like /multi_auth/github/callback
  user = multi_auth.user(params) # get signed in user

MultiAuth build with no dependency, it can be used with any web framework. Information about signed in user described in User class here src/multi_auth/user.cr. Supported providers src/multi_auth/providers. I hope it easy to add new providers.

Kemal integration example

<a href="/multi_auth/github">Sign in with Github</a>

MultiAuth.config("facebook", "facebookClientID", "facebookSecretKey")
MultiAuth.config("google", "googleClientID", "googleSecretKey")

def self.multi_auth(env)
  provider = env.params.url["provider"]
  redirect_uri = "#{Kemal.config.scheme}://#{env.request.host_with_port.as(String)}/multi_auth/#{provider}/callback"
  MultiAuth.make(provider, redirect_uri)
end

get "/multi_auth/:provider" do |env|
  env.redirect(multi_auth(env).authorize_uri)
end

get "/multi_auth/:provider/callback" do |env|
  user = multi_auth(env).user(env.params.query)
  p user.email
  user
end

Lucky integration example

# config/app.cr
class App
  URL = "http://localhost:3000"
end

# config/multi_auth_handler.cr
require "multi_auth"

class MultiAuthHandler
  MultiAuth.config("facebook", "facebookClientID", "facebookSecretKey")
  MultiAuth.config("google", "googleClientID", "googleSecretKey")

  def self.authorize_uri(provider : String)
    MultiAuth.make(provider, "#{App::URL}/oauth/#{provider}/callback").authorize_uri
  end

  def self.user(provider : String, params : Enumerable({String, String}))
    MultiAuth.make(provider, "#{App::URL}/oauth/#{provider}/callback")
  end
end

# src/actions/oauth/handler.cr
class OAuth::Handler < BrowserAction
  get "/oauth/:provider" do
    redirect to: MultiAuthHandler.authorize_uri(provider)
  end
end

# src/actions/oauth/handler/callback.cr
class OAuth::Handler::Callback < BrowserAction
  get "/oauth/:provider/callback" do
    user = MultiAuthHandler.user(provider, request.query_params)
    render_text user.email
  end
end

Contributors

• Sergey Makridenkov - creator, maintainer
• Vitalii Elenhaupt - contributor