Merge pull request #16386 from jvlcek/BZ_1505922_api_pop_up

External auth lookup_by_identity should handle missing request parameter
(cherry picked from commit a03cda1)

https://bugzilla.redhat.com/show_bug.cgi?id=1509416

app/models/authenticator/httpd.rb

@@ -70,13 +70,15 @@ def find_or_initialize_user(identity, username)
       [upn_username, user]
     end
 
-    def lookup_by_identity(username, request)
-      user_attrs, _membership_list = user_details_from_headers(username, request)
-      upn_username = "#{user_attrs[:username]}@#{user_attrs[:domain]}".downcase
+    def lookup_by_identity(username, request = nil)
+      if request
+        user_attrs, _membership_list = user_details_from_headers(username, request)
+        upn_username = "#{user_attrs[:username]}@#{user_attrs[:domain]}".downcase
 
-      user =   find_userid_as_upn(upn_username)
-      user ||= find_userid_as_distinguished_name(user_attrs)
-      user ||  case_insensitive_find_by_userid(username)
+        user =   find_userid_as_upn(upn_username)
+        user ||= find_userid_as_distinguished_name(user_attrs)
+      end
+      user || case_insensitive_find_by_userid(username)
     end
 
     private

spec/models/authenticator/httpd_spec.rb

@@ -62,6 +62,10 @@
 
     let(:username) { 'cheshire' }
 
+    it "Handles missing request parameter" do
+      expect(subject.lookup_by_identity('alice')).to eq(alice)
+    end
+
     it "finds existing users as username" do
       expect(subject.lookup_by_identity('alice', request)).to eq(alice)
     end