feature flag privacy pass

app/controllers/concerns/privacy_pass_supportable.rb

@@ -4,13 +4,16 @@ module PrivacyPassSupportable
   private
 
   def setup_privacy_pass_challenge
+    return unless privacy_pass_enabled?
+
     tokenizer = PrivacyPassTokenizer.new
     tokenizer.register_challenge_for_redemption(session.id)
     challenge = tokenizer.challenge_token
     response.set_header("WWW-Authenticate", "PrivateToken challenge=#{challenge}, token-key=#{PrivacyPassTokenizer.issuer_public_key}")
   end
 
-  def redeemed_privacy_pass_token?
+  def valid_privacy_pass_redemption?
+    return false unless privacy_pass_enabled?
     return session[:redeemed_privacy_pass] unless session[:redeemed_privacy_pass].nil?
 
     success = PrivacyPassRedeemer.call(request.headers["Authorization"], session.id)
@@ -21,4 +24,9 @@ def redeemed_privacy_pass_token?
   def delete_privacy_pass_token_redemption
     session.delete(:redeemed_privacy_pass)
   end
+
+  def privacy_pass_enabled?
+    ld_context = LaunchDarkly::LDContext.with_key(self.class.name)
+    Rails.configuration.launch_darkly_client.variation("privacy_pass.enabled", ld_context, false)
+  end
 end

app/controllers/sessions_controller.rb

@@ -7,12 +7,12 @@ class SessionsController < Clearance::SessionsController
   before_action :redirect_to_new_mfa, if: :mfa_required_not_yet_enabled?, only: %i[verify authenticate]
   before_action :redirect_to_settings_strong_mfa_required, if: :mfa_required_weak_level_enabled?, only: %i[verify authenticate]
   before_action :ensure_not_blocked, only: :create
-  before_action :present_privacy_pass_challenge, unless: :redeemed_privacy_pass_token?, only: :new
+  before_action :present_privacy_pass_challenge, unless: :valid_privacy_pass_redemption?, only: :new
   after_action :delete_mfa_expiry_session, only: %i[webauthn_create mfa_create]
 
   def create
     @user = find_user
-    if !redeemed_privacy_pass_token? && HcaptchaVerifier.should_verify_sign_in?(who)
+    if !valid_privacy_pass_redemption? && HcaptchaVerifier.should_verify_sign_in?(who)
       setup_captcha_verification
       render "sessions/captcha"
     elsif @user && (@user.mfa_enabled? || @user.webauthn_credentials.any?)
@@ -200,7 +200,8 @@ def setup_captcha_verification
 
   def present_privacy_pass_challenge
     setup_privacy_pass_challenge
-    render "sessions/new", status: :unauthorized
+    status = privacy_pass_enabled? ? :unauthorized : :ok
+    render "sessions/new", status: status
   end
 
   def login_conditions_met?

app/controllers/users_controller.rb

@@ -2,7 +2,7 @@ class UsersController < Clearance::UsersController
   include CaptchaVerifiable
   include PrivacyPassSupportable
 
-  before_action :present_privacy_pass_challenge, unless: :redeemed_privacy_pass_token?, only: :new
+  before_action :present_privacy_pass_challenge, unless: :valid_privacy_pass_redemption?, only: :new
 
   def new
     @user = user_from_params
@@ -11,7 +11,7 @@ def new
   def create
     @user = user_from_params
     render template: "users/new" and return unless @user.valid?
-    if !redeemed_privacy_pass_token? && HcaptchaVerifier.should_verify_sign_up?(request.remote_ip)
+    if !valid_privacy_pass_redemption? && HcaptchaVerifier.should_verify_sign_up?(request.remote_ip)
       setup_captcha_verification
       render "users/captcha"
     elsif @user.save
@@ -49,7 +49,8 @@ def setup_captcha_verification
   def present_privacy_pass_challenge
     @user = user_from_params
     setup_privacy_pass_challenge
-    render "users/new", status: :unauthorized
+    status = privacy_pass_enabled? ? :unauthorized : :ok
+    render "users/new", status: status
   end
 
   def user_params

test/integration/sign_in_test.rb

@@ -324,6 +324,7 @@ class SignInTest < SystemTest
     click_button "Verify"
 
     StatsD.expects(:distribution)
+
     assert page.has_content? "Multi-factor authentication"
 
     within(".mfa-form") do
@@ -335,6 +336,7 @@ class SignInTest < SystemTest
   end
 
   test "signing in when privacy pass is verified" do
+    Rails.configuration.launch_darkly_client.expects(:variation).with("privacy_pass.enabled", anything, anything).returns(true).at_least_once
     # privacy pass is meant to _not_ be machine automatable, so we're stubbing in this case
     PrivacyPassRedeemer.expects(:call).with(anything, anything).returns(true)
 
@@ -347,6 +349,7 @@ class SignInTest < SystemTest
   end
 
   test "signing in when privacy pass is not verified and captcha is not triggered" do
+    Rails.configuration.launch_darkly_client.expects(:variation).with("privacy_pass.enabled", anything, anything).returns(true).at_least_once
     # privacy pass is meant to _not_ be machine automatable, so we're stubbing in this case
     PrivacyPassRedeemer.expects(:call).with(anything, anything).returns(false)
 
@@ -359,6 +362,7 @@ class SignInTest < SystemTest
   end
 
   test "signing in when privacy pass is not verified and captcha is triggered" do
+    Rails.configuration.launch_darkly_client.expects(:variation).with("privacy_pass.enabled", anything, anything).returns(true).at_least_once
     @scope = Rack::Attack::LOGIN_THROTTLE_PER_USER_KEY
     update_limit_for("#{@scope}:#{@user.email}", 4, Rack::Attack::LOGIN_LIMIT_PERIOD)
     # captcha is meant to _not_ be machine automatable, so we're stubbing in this case

test/integration/sign_up_test.rb

@@ -112,6 +112,7 @@ class SignUpTest < SystemTest
   end
 
   test "sign up when privacy pass is verified" do
+    Rails.configuration.launch_darkly_client.expects(:variation).with("privacy_pass.enabled", anything, anything).returns(true).at_least_once
     # privacy pass is meant to _not_ be machine automatable, so we're stubbing in this case
     PrivacyPassRedeemer.expects(:call).with(anything, anything).returns(true)
 
@@ -126,6 +127,7 @@ class SignUpTest < SystemTest
   end
 
   test "sign up when privacy pass is not verified and captcha is not triggered" do
+    Rails.configuration.launch_darkly_client.expects(:variation).with("privacy_pass.enabled", anything, anything).returns(true).at_least_once
     # privacy pass is meant to _not_ be machine automatable, so we're stubbing in this case
     PrivacyPassRedeemer.expects(:call).with(anything, anything).returns(false)
 
@@ -140,6 +142,7 @@ class SignUpTest < SystemTest
   end
 
   test "sign up when privacy pass is not verified and captcha verification is triggered" do
+    Rails.configuration.launch_darkly_client.expects(:variation).with("privacy_pass.enabled", anything, anything).returns(true).at_least_once
     # privacy pass is meant to _not_ be machine automatable, so we're stubbing in this case
     PrivacyPassRedeemer.expects(:call).with(anything, anything).returns(false)