1 files changed, 16 insertions, 3 deletions
diff --git a/app/lib/sso/from_discourse.rb b/app/lib/sso/from_discourse.rb
index 94969c9..7af7173 100644
--- a/app/lib/sso/from_discourse.rb
+++ b/app/lib/sso/from_discourse.rb
@@ -5,6 +5,8 @@
 # frozen_string_literal: true
 
 module SSO
+  class MissingSecretError < ArgumentError; end
+
   class FromDiscourse
     attr_accessor :nonce, :token
     attr_reader   :request_uri, :user_info, :status
@@ -14,12 +16,12 @@ module SSO
       # This is a hash:
       # SSO::FromDiscourse.config = {
       #   sso_url: 'https://talk.incommon.cc/session/sso_provider',
-      #   return_url: "#{API_ROOT_URL}/my/account",
+      #   return_url: 'https://incommon-map.example/authenticate',
       #   sso_secret: Rails.application.credentials.sso_secret,
       # }
       # In config/routes.rb:
       # ...
-      # get 'my/account/:token' => 'authentications#sso_login'
+      # get 'authenticate/(:token)' => 'authentications#sso_login'
       attr_accessor :config
     end
 
@@ -91,7 +93,18 @@ module SSO
     end
 
     def mac_signature(payload = b64_payload)
-      OpenSSL::HMAC.hexdigest('SHA256', self.class.config[:sso_secret], payload)
+      OpenSSL::HMAC.hexdigest('SHA256', sso_secret, payload)
+    end
+
+    def sso_secret
+      @sso_secret = begin
+                      self.class.config[:sso_secret] ||
+                        Rails.application.credentials.sso_secret
+                    rescue MissingConstant
+                      nil
+                    end
+      raise SSO::MissingSecretError if @sso_secret.nil?
+      self.class.config[:sso_secret] ||= @sso_secret
     end
   end
 end