Gracefully handle wrong capitalization of username

app/controllers/web_key_directory_controller.rb

@@ -3,7 +3,7 @@ class WebKeyDirectoryController < WellKnownController
 
   # /.well-known/openpgpkey/hu/:hashed_username(.txt)
   def show
-    @user = User.find_by(cn: params[:l])
+    @user = User.find_by(cn: params[:l].downcase)
 
     if @user.nil? ||
        @user.pgp_pubkey.empty? ||

spec/requests/web_key_directory_spec.rb

@@ -64,6 +64,15 @@ RSpec.describe "OpenPGP Web Key Directory", type: :request do
         expect(response.body).to eq(expected_binary_data)
       end
 
+      context "with wrong capitalization of username" do
+        it "returns the pubkey as ASCII Armor plain text" do
+          get "/.well-known/openpgpkey/hu/yuca4ky39mhwkjo78qb8zjgbfj1hg3yf?l=JimmY"
+          expect(response).to have_http_status(:ok)
+          expected_binary_data = File.binread("#{Rails.root}/spec/fixtures/files/pgp_key_valid_jimmy.pem")
+          expect(response.body).to eq(expected_binary_data)
+        end
+      end
+
       context "with .txt extension" do
         it "returns the pubkey as ASCII Armor plain text" do
           get "/.well-known/openpgpkey/hu/yuca4ky39mhwkjo78qb8zjgbfj1hg3yf.txt?l=jimmy"