jneen/itch_io.rb

## itch_io.rb
module OmniAuth
  module Strategies
    class ItchIO
      include OmniAuth::Strategy

      option :name, 'itch_io'

      option :client_options,
        site: 'https://itch.io/',
        authorize_url: 'https://itch.io/user/oauth'

      args [:client_id, :client_secret]

      attr_reader :player, :access_token

      def client
        ::OAuth2::Client.new(options.client_id, options.client_secret, options.client_options.to_hash.transform_keys(&:to_sym))
      end

      def request_phase
        redirect client.implicit.authorize_url({ redirect_uri: callback_url }.merge(authorize_params))
      end

      def authorize_params
        state = SecureRandom.hex(24)

        session['omniauth.state'] = state

        { state: state, scope: 'profile:me' }
      end

      # [jneen] This is a quirk of the implicit OAuth2 flow which itch.io
      # uses. A redirect from an external site can only be a GET request,
      # and cannot contain any data in the body. This would normally cause
      # a leak of the client's token to the entire https stack.
      #
      # So instead it's passed as a hash param, which doesn't get sent to
      # the server. We have to serve up a web page that parses this info
      # out and makes a proper POST request to ourselves.
      #
      # As far as I can tell this is the standards-compliant way to do it,
      # and it's why they recommend only using the Implicit flow for
      # client-side apps. But this is the only flow implemented by Itch,
      # so it's what we're stuck with.
      def bounce_to_javascript
        [200, {'Content-Type' => 'text/html; charset=utf-8'}, <<~CONTENT]
          <html>
            <head>
              <title>redirecting...</title>
            </head>

            <body>
              <form method="post">
                <input type="hidden" name="state" />
                <input type="hidden" name="access_token" />
                <input type="submit" value="Click here if not redirected..." />
              </form>

              <script type="text/javascript">
                var params = new URLSearchParams(window.location.hash.slice(1));
                var form = document.getElementsByTagName('form')[0];
                form.action = window.location.pathname;
                form.state.value = params.get('state');
                form.access_token.value = params.get('access_token');
                form.submit();
              </script>
            </body>
          </html>
        CONTENT
      end

      def callback_phase
        return bounce_to_javascript if request.get?

        error = request.params['error_reason'] || request.params['error']

        state = request.params['state']

        if !state || state.empty? || state != session.delete('omniauth.state')
          return fail!(:csrf_detected, CallbackError.new(:csrf_detected, "CSRF detected"))
        elsif error
          err = CallbackError.new(
            request.params['error'],
            request.params['error_description'] || request.params['error_reason'],
            request.params['error_uri'],
          )
          return fail!(error, err)
        end

        token = request.params['access_token']
        fail!(:bad_params, 'missing access_token') unless token

        @access_token = ::OAuth2::AccessToken.new(client, token)
        response = @access_token.get('https://itch.io/api/1/key/me')

        if response.status != 200
          return fail!(:invalid_token, CallbackError.new(:invalid_token, "Invalid Token"))
        end

        parsed = response.parsed || {}

        @player = parsed['user'] || {}

        super
      end

      info do
        {
          "nickname" => @player['username'],
          "url" => @player["url"],
          "image" => @player["cover_url"],
        }
      end

      extra do
        @player.slice('gamer', 'press_user', 'developer')
      end

      uid do
        @player['id']
      end

      class CallbackError < StandardError
        attr_accessor :error, :error_reason, :error_uri

        def initialize(error, error_reason = nil, error_uri = nil)
          self.error = error
          self.error_reason = error_reason
          self.error_uri = error_uri
        end

        def message
          [error, error_reason, error_uri].compact.join(" | ")
        end
      end
    end
  end
end

OmniAuth.config.add_camelization 'itch_io', 'ItchIO'
OmniAuth.config.add_camelization 'itchio', 'ItchIO'
	module OmniAuth
	module Strategies
	class ItchIO
	include OmniAuth::Strategy

	option :name, 'itch_io'

	option :client_options,
	site: 'https://itch.io/',
	authorize_url: 'https://itch.io/user/oauth'

	args [:client_id, :client_secret]

	attr_reader :player, :access_token

	def client
	::OAuth2::Client.new(options.client_id, options.client_secret, options.client_options.to_hash.transform_keys(&:to_sym))
	end

	def request_phase
	redirect client.implicit.authorize_url({ redirect_uri: callback_url }.merge(authorize_params))
	end

	def authorize_params
	state = SecureRandom.hex(24)

	session['omniauth.state'] = state

	{ state: state, scope: 'profile:me' }
	end

	# [jneen] This is a quirk of the implicit OAuth2 flow which itch.io
	# uses. A redirect from an external site can only be a GET request,
	# and cannot contain any data in the body. This would normally cause
	# a leak of the client's token to the entire https stack.
	#
	# So instead it's passed as a hash param, which doesn't get sent to
	# the server. We have to serve up a web page that parses this info
	# out and makes a proper POST request to ourselves.
	#
	# As far as I can tell this is the standards-compliant way to do it,
	# and it's why they recommend only using the Implicit flow for
	# client-side apps. But this is the only flow implemented by Itch,
	# so it's what we're stuck with.
	def bounce_to_javascript
	[200, {'Content-Type' => 'text/html; charset=utf-8'}, <<~CONTENT]
	<html>
	<head>
	<title>redirecting...</title>
	</head>

	<body>
	<form method="post">
	<input type="hidden" name="state" />
	<input type="hidden" name="access_token" />
	<input type="submit" value="Click here if not redirected..." />
	</form>

	<script type="text/javascript">
	var params = new URLSearchParams(window.location.hash.slice(1));
	var form = document.getElementsByTagName('form')[0];
	form.action = window.location.pathname;
	form.state.value = params.get('state');
	form.access_token.value = params.get('access_token');
	form.submit();
	</script>
	</body>
	</html>
	CONTENT
	end

	def callback_phase
	return bounce_to_javascript if request.get?

	error = request.params['error_reason'] \|\| request.params['error']

	state = request.params['state']

	if !state \|\| state.empty? \|\| state != session.delete('omniauth.state')
	return fail!(:csrf_detected, CallbackError.new(:csrf_detected, "CSRF detected"))
	elsif error
	err = CallbackError.new(
	request.params['error'],
	request.params['error_description'] \|\| request.params['error_reason'],
	request.params['error_uri'],
	)
	return fail!(error, err)
	end

	token = request.params['access_token']
	fail!(:bad_params, 'missing access_token') unless token

	@access_token = ::OAuth2::AccessToken.new(client, token)
	response = @access_token.get('https://itch.io/api/1/key/me')

	if response.status != 200
	return fail!(:invalid_token, CallbackError.new(:invalid_token, "Invalid Token"))
	end

	parsed = response.parsed \|\| {}

	@player = parsed['user'] \|\| {}

	super
	end

	info do
	{
	"nickname" => @player['username'],
	"url" => @player["url"],
	"image" => @player["cover_url"],
	}
	end

	extra do
	@player.slice('gamer', 'press_user', 'developer')
	end

	uid do
	@player['id']
	end

	class CallbackError < StandardError
	attr_accessor :error, :error_reason, :error_uri

	def initialize(error, error_reason = nil, error_uri = nil)
	self.error = error
	self.error_reason = error_reason
	self.error_uri = error_uri
	end

	def message
	[error, error_reason, error_uri].compact.join(" \| ")
	end
	end
	end
	end
	end

	OmniAuth.config.add_camelization 'itch_io', 'ItchIO'
	OmniAuth.config.add_camelization 'itchio', 'ItchIO'